GEOSC 10 RockOns/Practice Quizzes

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What sort of rock is the dark material very close to the pink granitethat Dr. Alley is pointing to in the picture above? A) Sedimentary; The layering was caused by changes in the flow velocity of the river that deposited the material B) Sediment that isn't rock yet. The layers are alternating silt and sand from deposition from landslides off the Olympic Peninsula into the trench offshore. C) Metamorphic; The rock separated into layers as it was cooked and squeezed deep in a mountain range. D) Igneous; The layers were caused by flow processes during the eruption that released this. E) Marmot #2

Answer: Metamorphic; The rock separated into layers as it was cooked and squeezed deep in a mountain range. The large crystals, intergrown nature, and separate dark and light layers all point to metamorphism, deep inside a mountain range. Rapid cooling in volcanic eruptions gives tiny crystals, not the big, pretty ones here. You can see the former sand grains or other-sized pieces in sediment and sedimentary rocks. And marmot doo-doo consists of small, dark pellets, akin to big rabbit doots, and usually isn't considered to be rock.

In 2005, Hurricane Katrina brought a storm surge that overtopped the levees and flooded New Orleans, causing over 1400 deaths and perhaps $100 billion in damages. This flooding of New Orleans from a big storm was: A) An "act of nature" that no one could have foreseen; these things just happen. B) An event proving that if you drive your Chevy to the levee, it causes a hurricane to form. C) An event that scientists had warned about for decades, based on the known size of hurricanes, and the sinking of the city and the Delta. D) An event that proves that civil authorities are so good at planning that you never need to worry about dangers from any weather events in the future. E) A disaster that humans made much worse by causing massive sedimentation that raised the whole Mississippi Delta above the surface of the Gulf of Mexico, so that the storm waves could use the Delta as a ramp to jump easily into the city.

Answer: An event that scientists had warned about for decades, based on the known size of hurricanes, and the sinking of the city and the Delta. Scientists and planners did not know exactly when a big hurricane would hit New Orleans and threaten the city, but serious assessments had consistently highlighted the possibility for decades. The failures at New Orleans happened despite the fact that Katrina was NOT the "Big One"—on a scale of 1-5, Katrina was a 3 when it made landfall.

A larger national park and a smaller national park, otherwise identical, are completely surrounded by cornfields and Walmart parking lots, and have been surrounded for a century. You count the number of species of trees in each park. You probably will find: A) More species in the smaller park, because it lacks predators that keep diversity down. B) More species in the larger park, because it is more likely to have a Diet Pepsi distributor who pours acidic drinks on the inhabitants. C) The same number of species in the smaller park as in the larger park. D) More species in the smaller park, because the smaller size has caused faster evolution. E) More species in the larger park, because it can hold more individuals thus reducing the risk of extinction.

Answer: More species in the larger park, because it can hold more individuals thus reducing the risk of extinction. Diet Pepsi distributors are too smart to go around pouring drinks on beetles and bison; the bison might butt back! For evolution to make new species usually will take thousands of generations or longer, so a century is not long enough for new types to have appeared. The larger populations, which help prevent extinction, that are possible in the larger park will cause it to have more species.

Which is not part of our modern view of geology? A) Lithospheric plates move mainly horizontally on the soft, deeper material. B) The Earth's lithosphere is broken into a few major plates plus a few smaller ones. C) Most mountain building occurs in the centers of lithospheric plates. D) Convection occurs below the lithosphere in the deeper mantle. E) Lithospheric plates float on soft material deeper in the mantle.

Answer: Most mountain building occurs in the centers of lithospheric plates. Most mountain building occurs near the edges of lithospheric plates. All the others are accurate.

Dr. Alley is pointing to a brownish zone exposed in the low bluff along Coast Guard Beach, Cape Cod National Seashore. The brown zone is rounded on the bottom, flat on the top, rests on sand and gravel, and has sand dunes on top. In the lower picture, Dr. Alley is showing that the brown zone contains twigs and other organic material.What is the brown zone doing here? A) The brown zone is mostly the carcass of a dead whale, which was propelled here when highway-department workers dynamited it to get it off the beach. B) Humans dammed a nearby river, forming a lake that then filled with organic material. C) The brown zone is mostly the carcass of a dead whale, which washed up on the beach and was buried. D) A sinkhole opened here, forming a lake that was then filled with organic material. E) An ice block from the glacier was buried in sand and gravel, then melted to make a lake that filled with organic material.

Answer: An ice block from the glacier was buried in sand and gravel, then melted to make a lake that filled with organic material. Cape Cod is a creature of the glaciers, and most of the Cape's lakes started by melting of buried ice blocks. Sinkholes and human-made lakes do fill with organic material sometimes, but this is the wrong setting. A whale carcass wouldn't be twigs, etc. In Oregon, the highway department did once try dynamiting a whale carcass to speed natural decay, and succeeded in splattering bystanders and even denting some car roofs with large flying whale parts. (One has to wonder whether there exists a rock band somewhere named "Large Flying Whale Parts".)

The picture above shows an outcrop along Interstate 70 in Utah. The green arrow points to a person, for scale. Between the pink arrows there is an interesting surface.What is it? A) The side of a sand dune, where the wind blew away the sand on top. B) An unconformity, where erosion occurred before the rocks above were deposited. C) The quarry from which they collected the rocks used to make the president's new desk. D) A mud crack, with the layer on top having fallen down the crack. E) A fault, where rocks have been shoved over other rocks.

Answer: An unconformity, where erosion occurred before the rocks above were deposited. The rocks below were tipped up on end by mountain-building processes associated with the early growth of the Rocky Mountains. Erosion cut the lower rocks off, a soil developed, and then a lake flooded in and deposited limestone.

The picture above shows an outcrop along Interstate 70 in Utah. The green arrow points to a person, for scale. Between the pink arrows, there is an interesting surface. What is it? A) The side of a sand dune, where the wind blew away the sand on top. B) The quarry from which they collected the rocks used to make the president's new desk. C) A mud crack, with the layer on top having fallen down the crack. D) An unconformity, where erosion occurred before the rocks above were deposited. E) A fault, where rocks have been shoved over other rocks.

The age of the Earth can be estimated in many ways. Which statement below is most accurate (remember that uniformitarian calculations involve looking at the thickness and type of sedimentary rocks, and similar things, but do NOT include radiometric dating or counting of annual layers)? A) Annual-layer counting shows that the Earth is 4.6 billion years old. B) Annual-layer counting shows that the Earth is more than about 100 thousand years old, uniformitarian calculations show that the Earth is more than about 100 million years old, but we don't know how to estimate how much more than 100 million years the Earth is. C) Annual-layer counting shows that the Earth is more than about 100 million years old. D) Annual-layer counting shows that the Earth is more than about 100 thousand years old, uniformitarian calculations show that the Earth is more than about 100 million years old, and radiometric techniques tell us how old the Earth is. E) Uniformitarian calculations show that the Earth is 4.6 billion years old.

Answer: Annual-layer counting shows that the Earth is more than about 100 thousand years old, uniformitarian calculations show that the Earth is more than about 100 million years old, and radiometric techniques tell us how old the Earth is.

If you get some of the right sort of organic material, and heat it in the right sort of way, perhaps with a little squeezing, you will end up with coal. The most-heated is the most valuable. In order, from the MOST-VALUABLE/MOST-HEATED (FIRST) to the least-valuable/least-heated (LAST), the coals (and material that gives coal) are: Anthracite, bituminous, lignite, peat. Peat, lignite, bituminous, anthracite. Peat, anthracite, lignite, bituminous. Bituminous, peat, anthracite, lignite. Bituminous, peat, lignite, anthracite.

Answer: Anthracite, bituminous, lignite, peat. This is mostly memorization. But the names hide a lot of history, the peat-bog cutters of Ireland, the brown lignites now being mined in Wyoming, the deep-mines and strip-mines of the bituminous coals of western Pennsylvania, West Virginia and elsewhere, and the hard-coal anthracite of the Scranton and Wilkes-Barre region. If you don't know any of this history, you might consider reading up on it a bit; it is fascinating.

Transitional forms between distinct types (species) of different ages in the fossil record: A) Are never referred to in the debate about evolution. B) Prove that the theory of evolution is wrong. C) Are common for commonly fossilized types, but rare for rarely fossilized types. D) Are known for all types. E) Do not occur.

Answer: Are common for commonly fossilized types, but rare for rarely fossilized types. Most living things are recycled, not fossilized. Most of the world is eroding, so no fossils are made in most places. Where fossils are being made, only a few percent of living types typically end up producing fossils. And in those few types, new species often appear in small, isolated populations. But careful search has shown many, many transitions in commonly fossilized types. In rarely fossilized types, transitions are much rarer. Lots of people refer to transitional forms in debating evolution. Anti-evolutionists often claim that transitional forms are unknown. When transitional forms are demonstrated, the anti-evolutionists usually argue that all known transitions are "micro-evolution" which somehow is not "real" or "macro-evolution". Because some transitions will always be missing, there is no way to show every possible transition in the fossil record, so this anti-evolutionist argument can't be totally disproven. But that does not make this argument a good one.

Tsunamis: A) Are like tornadoes; they can be predicted with some accuracy seconds to hours before they strike in most cases, allowing quick warnings to save many lives. B) Always are huge and destructive. C) Are completely unpredictable on all time scales. D) Are like the seasons; they can be predicted accurately months in advance, allowing wise planning. E) Are like the weather; they can be predicted fairly accurately days in advance, allowing wise planning.

Answer: Are like tornadoes; they can be predicted with some accuracy seconds to hours before they strike in most cases, allowing quick warnings to save many lives. Because tsunamis are triggered by earthquakes, among other things, and we cannot predict earthquakes accurately, we cannot make months-in-advance predictions of tsunamis. The p-waves from the earthquakes that cause the most common tsunamis move much more rapidly than the tsunamis do, allowing timely warnings; however, because the tsunamis get where they are going in hours or less typically, not much time is available. Water does go out before rushing in along some coasts, but comes in before going out along other coasts, waves have "up" and "down" parts, and some coasts get an "up" first while other coasts get a "down" first. Little earthquakes make little tsunamis; big earthquakes make big tsunamis.

Tsunamis: A) Are like the weather; they can be predicted fairly accurately days in advance, allowing wise planning. B) Always are huge and destructive. C) Are completely unpredictable on all time scales D) Are like tornadoes; they can be predicted with some accuracy seconds to hours before they strike in most cases, allowing quick warnings to save many lives. E) Are like the seasons; they can be predicted accurately months in advance, allowing wise planning.

The deepest earthquakes are rare, and differ in some ways from the more-common type of quakes. These deepest earthquakes probably: A) Are caused by Coke drinkers kicking Pepsi machines and then jumping back when Gatorade squirts out. B) Are the shaking of the ground caused by elastic rebound of bent rocks when a fault breaks. C) Are caused by atomic-bomb testing. D) Are caused by Pepsi machines exploding after being kicked by Coke drinkers to cause Gatorade to squirt out. E) Are the shaking of the ground caused by "implosion" as minerals rearrange to denser forms as the pressure on them rises in downgoing slabs.

Answer: Are the shaking of the ground caused by "implosion" as minerals rearrange to denser forms as the pressure on them rises in downgoing slabs. "Implosion" is the currently favored idea. As subduction zones take rocks deeper where pressure is higher, the building blocks tend to reorganize to take up less space, shifting from, say, a one-on-top-of-another pattern to a fit-in-the-space-between-those-below pattern. Sometimes, this seems to be delayed and then to happen all at once (I can't move until my neighbor does...), giving an implosion. The biggest, deepest earthquakes happen where temperatures and pressures are so high that we don't think rocks can break. Humans have never made a hole anywhere nearly as deep as the deeper earthquakes. We have mostly quit testing atomic bombs. And, a big earthquake is way bigger than a big atomic bomb. And, no one has ever put a soda machine deep enough to account for the deepest earthquakes.

The recent changes in the amount of ice on Earth over time occurred: A) At regular and repeating times, controlled by redistribution of sunlight on the surface of the Earth in response to features of Earth's orbit, even though total sunshine received by the planet didn't change much. B) At random times, controlled by redistribution of sunlight on the surface of the Earth in response to features of Earth's orbit, even though total sunshine received by the planet didn't change much. C) Because flocks of giant ptarmigan and herds of giant marmots clustered on the edges of the ice sheets, which melted the ice. D) At regular and repeating times, controlled by the very large changes in total sunshine received by the Earth in response to features of Earth's orbit. E) At random times, in response to very large changes in the total sunshine received by the Earth in response to features of Earth's orbit.

Answer: At regular and repeating times, controlled by redistribution of sunlight on the surface of the Earth in response to features of Earth's orbit, even though total sunshine received by the planet didn't change much. The orbital changes have little effect on the total sunshine, but do move that sunshine around, with important consequences. And the orbital changes are far from random, having very strong regularities. We'd love to have seen flocks of ptarmigan and herds of marmots, but no one has found their bones, so it is highly likely that they did not exist.

The recent changes in the amount of ice on Earth over time occurred: A) At regular and repeating times, controlled by redistribution of sunlight on the surface of the Earth in response to features of Earth's orbit, even though total sunshine received by the planet didn't change much. B) At regular and repeating times, controlled by the very large changes in total sunshine received by the Earth in response to features of Earth's orbit. C) Because flocks of giant ptarmigan and herds of giant marmots clustered on the edges of the ice sheets, which melted the ice. D) At random times, in response to very large changes in the total sunshine received by the Earth in response to features of Earth's orbit. E) At random times, controlled by redistribution of sunlight on the surface of the Earth in response to features of Earth's orbit, even though total sunshine received by the planet didn't change much.

In a glacier, the ice moves fastest: A) At the bed on some glaciers, halfway between the bed and the surface on other glaciers, and at the surface on still other glaciers. B) At the bed, where ice meets rock. C) Halfway between the bed and the surface. D) At the upper surface, where ice meets air. E) When trying to escape from Pepsi commercials.

Answer: At the upper surface, where ice meets air. The ice at the surface rides along on that beneath but deforms a bit on its own, and so goes fastest. The fast-food ketchup-packet model in which the mid-depth ice goes fastest would require that the upper and lower pieces be especially strong and rigid (which they aren't; and, it might require someone huge stomping on the glacier). The bed is held back by friction with the rock. And ice lacks the sentience needed to attempt to avoid commercials.

Look at the picture above, which shows a small section of a "fossil" sand dune (a sand dune in which the grains have been "glued" together by hard-water deposits). When the dune was first deposited, which was up (which letter is closest to the arrow that is pointing in the direction you would have looked to see the sky when the dune was deposited)? D B C A

Answer: B Just to the left of the letter ï¿½Bï¿½ there is a small unconformity. The layers farther to the left are cut along that surface. Layers must exist to be cut, so the left-hand layers are older, the right-hand layers are younger, and ï¿½upï¿½ was to the right.

The above diagram is from one of the Geomations in the unit. It shows three possible fault styles. A and B are cross-sections, with a collapsed building on top to show you which way is up—the yellow band is a distinctive layer of rock that was broken by the earthquake that also knocked down the building. C is viewed from a helicopter, looking down on a road with a dashed yellow line down the middle; the road was broken by an earthquake along the green fault, and the earthquake knocked down a building to make the funky-looking brown pile in the upper right.What is accurate about the different earthquake styles? A) B is push-together, C is slide-past, and A is pull-apart. B) B is pull-apart, C is slide-past, and A is push-together. C) B is slide-past, C is push-together, and A is pull-apart. D) B is pull-apart, C is push-together, and A is slide-past. E) B is push-together, C is slide-past, and A is pull-apart.

Answer: B is pull-apart, C is slide-past, and A is push-together. Imagine putting the image on paper, cutting out the blocks (one block on each side of the fault), and then sliding them back together to make the original, unbroken features. A and B stand up from the table, C lies down on the table. Now, slide them to make the picture as seen here. In A, you'll be moving the right-hand block up and toward the other block, so it is push-together. In B, you'll be moving the right-hand block down and away from the other block, so it is pull-apart. And in C, you'll slide one past the other (geologists distinguish right-lateral and left-lateral motion for C, but you don't have to worry about that much detail).

Which of the following is not expected very often near a "textbook" subduction zone (that is, near a subduction zone that is so perfect and free of confusing complications that you would use it in a textbook to teach students)? A) Piles of sediment scraped off the slab being subducted. B) Push-together earthquakes and faults as the subducting slab squeezes the rocks. C) Andesitic volcanoes such as Crater Lake, fed by melt from the slab being subducted. D) Basaltic hot-spot volcanoes such as Hawaii. E) Stratovolcanoes such as Mt. St. Helens, formed by lava flows and explosions form the slab being subducted.

Answer: Basaltic hot-spot volcanoes such as Hawaii.

The sea floor that forms at spreading ridges and then moves away will: A) Be subducted, with most of the material going back into the mantle, balancing the material coming out to make the new sea floor. B) Remain at the surface of the earth forever, resulting in the earth getting bigger and bigger every year. C) Remain at the surface of the earth forever, but the earth isn't getting bigger because the insides of the earth are shrinking as they cool off rapidly. D) Be ground up by glaciers, blown away by wind, and eventually escape to space in the solar wind. E) Be bulldozed and used as construction material for new buildings in Washington.

Answer: Be subducted, with most of the material going back into the mantle, balancing the material coming out to make the new sea floor. Seafloor rocks are generally not very old (perhaps 160 million years old at the most). By contrast, continental rocks are up to 4 billion years old. The reason is that seafloor rocks are created (at midocean spreading ridges) and then consumed (at subduction zones) continuously, and at about the same rate. Oceanic rocks are denser than continental rocks, so when the two types of rocks collide, oceanic rocks sink into the mantle and are recycled. A tiny bit of hydrogen escapes from the planet in the solar wind, but not much else.

Convection occurs: A) Because hotter things are more dense and tend to rise. B) Because hotter things are more dense and tend to sink. C) In liquids only. D) Because hotter things are less dense and tend to rise. E) In solids only.

Answer: Because hotter things are less dense and tend to rise. Almost everything expands from heating, taking up more space with the same weight and so becoming less dense. Gases, liquids, and sufficiently soft solids can convect if heated from below, with warming of the lower layer causing it to rise.

Bigger earthquakes occur less frequently, but a bigger quake releases more energy and does more damage. An interesting question to ask about earthquakes (and about almost anything else!) is whether the increase in energy release and damage done is larger or smaller than the decrease in frequency as one looks at bigger earthquakes. Asked a different way, is most of the damage done by the many little earthquakes or by the few big earthquakes? A) The drop-off in frequency just balances the rise in energy, so all earthquake sizes contribute equally to global earthquake damages. B) Most of the damage is done by the few, big earthquakes. C) Earthquakes don't do any damage, so this is a silly question. D) Earthquakes only damage Coke machines, under an exclusive contract with Pepsi. E) Most of the damage is done by the many, little earthquakes.

Answer: Most of the damage is done by the few, big earthquakes. An increase of 1 in magnitude increases ground shaking about 10-fold, increases energy release about 30-fold, and decreases frequency about 10-fold; the 30-fold increase in energy more than offsets the 10-fold decrease in frequency of occurrence. We wish earthquakes did no damage, but the millions of people who have been killed in earthquakes over the centuries would, if they could, testify to the damage done by earthquakes. And earthquakes are actually very poor at distinguishing the brands of soda dispensed by or advertised on machines.

Some natural resources are renewable—nature produces them fast enough that humans can obtain valuable and useful supplies of a resource without depleting it. Other natural resources are nonrenewable—if we use the resource at a rate fast enough to matter to our economy, the resource will run out because use is much faster than natural production. What do we know about oil and coal? A) Both oil and coal are nonrenewable resources, and at current usage rates and prices similar to today, oil will run out in about a century and coal will run out in a few centuries. B) Oil is a nonrenewable resource, but coal is made more rapidly, especially in coastal mangrove swamps, and so is a renewable resource. C) Coal is a nonrenewable resource, but oil is made more rapidly in places such as large river deltas and so is a renewable resource. D) Both oil and coal are nonrenewable resources, and at current usage rates and prices similar to today, both will last about one century before running out. E) Both oil and coal are renewable resources; they are being made rapidly by natural processes in places such as ANWR on the North Slope of Alaska, and in sea-floor regions off the continental shelf.

Answer: Both oil and coal are nonrenewable resources, and at current usage rates and prices similar to today, oil will run out in about a century and coal will run out in a few centuries. There is lots more coal than oil; oil has this habit of floating on water, thus rising through rocks and escaping to the sea floor where the oil is "burned" for energy by bacteria or other creatures. The size of the resource, in coal, oil, or anything else, depends on the price, and how long the resource lasts depends on rate of use, which is increasing rapidly for fossil fuels. The idea that immense pools of oil are out there, undiscovered but easy to get, is pretty silly—oil companies are really smart, drilled the easy stuff early on, and are now running out of oil that can be drilled and produced at prices close to modern.

The Petrified Forest of Arizona includes a great diversity of fossils. In the picture above, paleontologist Randall Irmis excavates a plate from a specimen of Buettneria.Based on the discussions of evolution in the class materials, it is likely that: A) Buettneria is essentially identical to species still alive today. B) Buettneria is related to, but recognizably different from, species still alive today. C) Buettneria is completely unrelated to species still alive today.

Answer: Buettneria is related to, but recognizably different from, species still alive today. Evolutionary theory indicates that living things change from generation to generation, but that all living things are related. Consistent with this, Buettneria is recognizably similar to, yet different from, amphibians still alive today.

You are the chief biodiversity officer for the National Park Service in the eastern US, responsible for maintaining as much diversity as possible, and your boss has told you to focus on maintaining biodiversity of things big enough to see with the naked eye (so you don't need to worry about microorganisms). You have two parks, and enough money to buy 10,000 acres of land. You may add the 10,000 acres to one of the parks, add 5,000 acres to each park while leaving them as isolated parks, or buy a 10,000-acre corridor connecting the two parks. All of the land for sale is now wilderness, but the land you do not buy is going to be paved for a super-mega-mall. You would be wise to: A) Buy the corridor connecting the two parks; this keeps one big "island" rather than two smaller ones, and so keeps more species. B) Enlarge one park a good bit; bigger islands have more species, so you want to make a big "island". C) Enlarge both parks some; each park has some diversity, and you want to enhance both. D) Don't worry, the key is how much area you have in wilderness, so each of the plans is equally valuable. E) Don't worry; malls are highly biodiverse, so you'll succeed no matter what you do.

Answer: Buy the corridor connecting the two parks; this keeps one big "island" rather than two smaller ones, and so keeps more species. Remember the terrarium—you will have more diversity in an undivided terrarium than in a divided one. Your park area is your terrarium; keep it undivided. Malls have low biodiversity.

Look at the picture above, which shows a small section of a "fossil" sand dune (a sand dune in which the grains have been "glued" together by hard-water deposits).When the dune was first deposited, which was up (which letter is closest to the arrow that is pointing in the direction you would have looked to see the sky when the dune was deposited)? A C D B

Answer: C Just above the letter "C" there is a small unconformity. The layers above are cut along that surface. Layers must exist to be cut, so the layers above that surface are older, the lower layers are younger, and "up" was toward the bottom.

Which formula most closely describes the process by which plants make more of themselves: Diet_Coke + Mentos → Boom CO2 + H2O + energy → CH2O + O2 CH2O + O2 → CO2 + H2O + energy CaCO3 + H2CO3 → Ca+2+ 2HCO3- Ca+2 + 2HCO3- → CaCO3 + H2CO3

Answer: CO2 + H2O + energy → CH2O + O2 CaCO3 is shell or cave-rock; the equation with CaCO3 on the left is dissolution of rock to make caves, and with CaCO3 on the right is formation of shells. CH2O is a pretty good estimate of average plant composition; the equation with CH2O on the left is burning of plant material for energy, and with CH2O on the right is how plant material is made. Diet Coke plus Mentos does produce an interesting effect, but this is not the way plants grow.

The geologic time scale is, starting with the youngest and ending with the oldest: A) Mesozoic, Cenozoic, Paleozoic, Precambrian. B) Cenozoic, Precambrian, Paleozoic, Mesozoic. C) Cenozoic, Paleozoic, Mesozoic, Precambrian. D) Cenozoic, Mesozoic, Paleozoic, Precambrian. E) Paleozoic, Mesozoic, Cenozoic, Precambrian.

Answer: Cenozoic, Mesozoic, Paleozoic, Precambrian. You could probably reason this out if you remember some Greek roots, or else just memorize it—Cenozoic is youngest, then Mesozoic, Paleozoic, and Precambrian.

Clay consists of new minerals commonly formed by: A) Chemical weathering of quartz (quartz is pure silica) B) Combination of iron with water and oxygen C) Evaporation of water leaving the salts it was carrying D) Combination of acid rain with limestone. E) Chemical weathering of feldspar (feldspar contains silica, aluminum, potassium and other things)

Answer: Chemical weathering of feldspar (feldspar contains silica, aluminum, potassium and other things) When weathering attacks feldspar, some things are washed away, water is added, there is a little rearrangement of the chemicals, and clay results. Quartz, which is pure silica, mostly just sits around not doing much. Weathering usually dissolves a little bit of quartz, but this leaves a smaller piece of quartz and doesn't make anything new. Hence, when weathering attacks granite, the quartz pieces in the granite become quartz sand in the soil that is formed.

The United Nations, under the auspices of the Intergovernmental Panel on Climate Change, has attempted to assess the scientific understanding of how greenhouse-gas emissions will affect the climate, and thus people. The UN reports show that if we continue on our present path, burning fossil fuels at a faster and faster rate: A) Climate will change, primarily getting warmer, and these changes will hurt everyone, equally. B) Climate will change, primarily getting warmer, and those changes will primarily hurt poor people in warm places, but the climate changes are primarily being caused by wealthier people in colder places. C) Climate will change, with cooling at high latitudes that primarily will hurt wealthy people living in those cold places. D) Climate will change, primarily getting warmer, and those changes will primarily hurt the poor people in warm places who are the main causes of the climate changes through deforestation and other actions. E) Climate will change, primarily getting colder, and those changes will especially hurt those people living in northwestern Europe.

Answer: Climate will change, primarily getting warmer, and those changes will primarily hurt poor people in warm places, but the climate changes are primarily being caused by wealthier people in colder places. Blizzards play havoc with airline travel, which hurts the economy in the mid- and high-latitude wealthier countries. If you have winter (so that warming reduces blizzards), air conditioners (so you can keep the economy humming when the weather is otherwise too hot), and bulldozers (so you can build sea walls or haul things out of the way as the ocean rises), a little warming might even help your economy, although too much warming will be bad. If you are missing any of winter, air conditioning, or bulldozers, all warming is likely to be bad. Most of the world's people are missing all three, and will be hurt by warming, but the warming is being caused primarily by people who have all three.

Among fossil fuels: A) Coal is made by heating of woody plant material, and oil is made by heating of algae. B) Oil is made by heating of algae, and coal is made by heating of different algae. C) Oil is made by spraying WD-40 on duct tape, and coal is made by being bad so Santa delivers it to your stocking. D) Coal is made by heating of woody plant material, and oil is made by heating of different woody plant material. E) Oil is made by heating of woody plant material, and coal is made by heating of algae.

Answer: Coal is made by heating of woody plant material, and oil is made by heating of algae. Slimy algae gives slimy oil; chunky wood gives chunky coal. Works great. Duct tape and WD-40 are the quick-fix tool kit; if something moves but it shouldn't, apply duct tape, and if something doesn't move but it should, apply WD-40. None of you would be so bad as to merit coal in your stocking, but we presume Santa gets it from a mine somewhere.

Among fossil fuels: A) Oil is made by heating of plant material deposited on land, and coal is made by heating of plant material deposited in water. B) Oil is made by heating of woody plant material, and coal is made by heating of algae. C) Coal is made by heating of woody plant material, and oil is made by heating of algae. D) Oil is made by spraying WD-40 on duct tape, and coal is made by being bad so Santa delivers it to your stocking. E) Coal is made by heating of plant material deposited on land, and oil is made by heating of plant material deposited in water.

Major differences between Mt. St. Helens and Hawaiian volcanoes include: A) Mt. St. Helens is a medium-to-high-silica, explosively erupting shield volcano, and Hawaii has low-silica, explosively erupting stratovolcanoes. B) Mt. St. Helens is a volcano, but Hawaii doesn't have any volcanoes, and never has. C) Mt. St. Helens is a medium-to-high-silica, explosively erupting stratovolcano, and Hawaii has low-silica, quietly erupting shield volcanoes. D) Mt. St. Helens is a low-silica, explosively erupting shield volcano, and Hawaii has medium-to-high-silica, quietly erupting stratovolcanoes. E) Mt. St. Helens is a low-silica, quietly erupting stratovolcano, and Hawaii has medium-to-high-silica, explosively erupting shield volcanoes.

Answer: Mt. St. Helens is a medium-to-high-silica, explosively erupting stratovolcano, and Hawaii has low-silica, quietly erupting shield volcanoes. The low-silica lava from the Hawaiian hot spot flows easily without large explosions, so the lava spreads out to make broad, gentle volcanoes that look like shields of medieval warriors. Melt a little basaltic sea floor with some water and sediment, and you get silica-rich andesite feeding explosive, subduction-zone stratovolcanoes such as Mt. St. Helens. Hot spots and spreading ridges make low-silica, basaltic volcanoes, which don't explode powerfully. Mt. St. Helens is a stratovolcano, but stratovolcanoes are steep, not broad and flat. Mt. St. Helens was the most active of the Cascades volcanoes even before its big 1980 eruption, and the volcano has erupted many times since the big eruption.

Geological evidence based on several radiometric techniques has provided a scientifically well-accepted age for the Earth. Represent that age of the Earth as the 100-yard length of a football field, and any time interval can be represented as some distance on the field. (So something that lasted one-tenth of the age of the Earth would be ten yards, and something that lasted one-half of the age of the Earth would be fifty yards.) On this scale, how long have you personally been alive? A) Much less than the thickness of a sheet of paper. B) 1 yard. C) 50 yards. D) 10 yards. E) 1 inch.

Answer: Much less than the thickness of a sheet of paper. If the 4.6 billion years of Earth history are 100 yards, then the few thousand years of written history are just one-millionth of that history, just over the thickness of a sheet of paper. And your small piece of written history must be only a small fraction of a sheet of paper, roughly 1/200th or so. PreviousNext

The processes that made Death Valley have been operating for millions of years, and continue to operate today. For this question, ignore the sand and gravel moved by water and wind, and think about the big motions of the rocks beneath. If you had visited Death Valley 1 million years ago, you would have found the valley then to have been (choose the best answer): A) The same width and depth as it is today. B) Wider than it is today, with no change in the depth. C) Wider and deeper than it is today. D) Deeper than it is today, with no change in the width. E) Narrower and shallower than it is today.

Answer: Narrower and shallower than it is today. The pull-apart action that is spreading Death Valley and surroundings also involves uplift of mountains or downdrop of valleys, and Death Valley has dropped as its flanking mountains have moved apart. Thus, in the past the valley was narrower and shallower than it is now, and the motions have deepened and widened the valley.

Air can be heated in many different ways. At night, if air moves up one side of a mountain range such as the Sierra Nevada, raining or snowing on the way, and then down the other side, the air is hotter after moving over than it was before. What is the main reason, as discussed in the class materials? A) Forest fires that are always burning in the Sierra make the air a whole lot hotter. B) Moonlight is so bright that it heats the air a lot. C) Moving air is always heated a lot by friction with the trees beneath. D) The Earth's rotation turns air into tornadoes and hurricanes by the Coriolis effect, and this turning makes the air warmer. E) Condensation of water vapor to form clouds and rain releases heat that was stored when the water evaporated.

Answer: Condensation of water vapor to form clouds and rain releases heat that was stored when the water evaporated. Much of the sun's energy that falls on the tropics is stored by evaporating water, and only later made so you can feel it (called sensible heat) when condensation reverses the evaporation. Winds are driven by pressure differences, and do curve in response to the Earth's rotation, and there is a little bit of heat generation from friction, but you should probably know that standing outside in the wind does not make you hot as the frictional heating occurs around your body—the frictional heat is very small. (If the air were moving past you at many times the speed of sound, the frictional heat would become large, as shown by meteorites "burning up" in the atmosphere, and the need for heat shields on spacecraft re-entering the atmosphere. And while marmots do produce a little methane, and a bit of heat, they don't produce nearly enough to matter to the climate.

Subduction zones produce an amazing variety of geological features. These include: A) Deep trenches in the sea floor, which are really fjords eroded by glaciers flowing down from the mountains and away from the coast out to sea. B) Deep trenches in the sea floor, which are old river valleys eroded by the vigorous streams flowing down from the mountains. C) Deep trenches in the sea floor, formed by the weight of discarded Microsoft Windows CDs and Starbucks coffee cups, heaved into the ocean from Seattle by angry consumers. D) Deep trenches in the sea floor, formed by the bending of the downgoing plate, and sometimes filled with sea water but sometimes filled with sediment eroded from nearby land. E) Deep trenches in the sea floor, formed by the bending of the downgoing plate, but filled with basaltic lava flows from the hot spots that feed the subduction-zone volcanoes.

Answer: Deep trenches in the sea floor, formed by the bending of the downgoing plate, and sometimes filled with sea water but sometimes filled with sediment eroded from nearby land. The deepest spots in the ocean are formed when downgoing slabs are bent downward to make deep trenches parallel to the shore. However, sometimes these trenches become sediment-filled. Microsoft CDs are a relatively small part of that sediment. Rivers don't cut below sea level, and glaciers flowing away from the coast cannot cut a huge trench parallel to the coast.

Glaciers move by: A) Deformation within the ice, and sometimes sliding over materials beneath or deformation within materials beneath. B) Deformation within the ice, and sometimes sliding over materials beneath. C) Deformation within materials beneath and sliding over those materials, and sometimes by deformation within the ice. D) Deformation within the ice. E) Deformation within materials beneath, and sometimes by sliding over those materials or by deformation within the ice.

Answer: Deformation within the ice, and sometimes sliding over materials beneath or deformation within materials beneath. Deformation within the ice is essentially the definition of a glacier, so that is always present. When the bed is warmed by heat from the Earth, the ice can slide over materials beneath, and may also deform till beneath.

When considering the land surface: A) Deposition of sediments does not occur on land, so there is no way to figure out anything about geologic history. B) Deposition of sediments occurs in only a few places, with erosion or nondeposition occurring in most places to produce unconformities, and there is no way to figure out anything about geologic history. C) Deposition of sediments occurs in only a few places, with erosion or nondeposition occurring in most places to produce unconformities, and one must piece together geologic history from rocks in many places. D) Deposition of sediments is occurring on it in most places most of the time, so you can go almost anywhere and find a complete or nearly complete record of geologic history. E) Deposition of sediments occurs in only a few places, with erosion or nondeposition occurring in most places to produce inclusions, and one must piece together geologic history from rocks in many places.

Answer: Deposition of sediments occurs in only a few places, with erosion or nondeposition occurring in most places to produce unconformities, and one must piece together geologic history from rocks in many places. An unconformity is a surface of erosion or nondeposition in a pile of sediments or sedimentary rocks. Most of the land surface is eroding most of the time, with deposition restricted, so it takes some careful study to sort out geologic history. Nonetheless, a lot of geologists working over a lot of centuries have revealed a surprisingly complete history of the planet.

Two neutral atoms have the same number of protons in the nucleus, but different numbers of neutrons. These are: A) Different isotopes of the same element. B) Different packaging of the same cola. C) Different ions of the same element. D) Different elements. E) Different isopleths of the same element.

Answer: Different isotopes of the same element. The element is determined by the number of protons, so if each atom has the same number of protons, the atoms are the same element. Changing the number of neutrons primarily affects the weight, giving a different isotope of the same element. (Changing the number of neutrons too much can introduce radioactivity, so the isotope won't hang around forever.) Ions are made by gaining or losing electrons. Isopleths are lines on a map connecting places with the same concentration of something that someone has measured, not exactly relevant here. And cola requires making atoms into molecules, and then mixing molecules of several sorts (water, sweetener, coloring agent, flavoring agent, perhaps caffeine) to make cola.

Which of the following is part of the modern theory of evolution? A) Evolution always produces bigger and more-complicated living things from smaller and simpler living things. B) Diversity exists within a species, and "experiments" that tend to promote diversity sometimes occur during reproduction. C) Evolution proceeds in the direction desired by members of a generation. D) If the body of an adult living thing is changed by its environment, those changes usually are passed on biologically to children. E) Evolution usually proceeds by birth of "hopeful monsters" involving very large changes from one generation to the next.

Answer: Diversity exists within a species, and "experiments" that tend to promote diversity sometimes occur during reproduction. No matter how hard you and your friends wish that your children will be born with the ability to fly unassisted, the kids will have to use airlines like the rest of us. You can get a tattoo without worry that your children will be born with that same tattoo. A hopeful monster would have no one to mate with. And while sometimes bigger or more-complex kids do better, sometimes smaller or simpler ones do better. But, biological "experimentation" promoting diversity does occur, providing the variability on which natural selection occurs to cause evolution.

The volcanoes of the island of Hawaii eventually will: A) Drift off the hot spot and cease to erupt, while a new volcano grows to their southeast. B) Blow up as powerfully as the main 1980 eruption of Mt. St. Helens. C) Rise out of the ocean as they cool and sink, and are eroded. D) Blow up as powerfully as the main eruptions of Yellowstone, 1000 times bigger than Mt. St. Helens. E) Last forever while nothing happens to them except for development of a protective layer of condominiums.

Answer: Drift off the hot spot and cease to erupt, while a new volcano grows to their southeast. As they drift off the hot spot, the Hawaiian chain volcanoes lose their source of melt and quit erupting. But, a new volcano grows. Indeed, the new one, Loihi Seamount, is already there and erupting underwater, building toward the surface. As they cool and sink, and are eroded, the Hawaiian volcanoes disappear below sea level. Hawaiian volcanoes are "friendly", not having highly explosive eruptions. Yellowstone is an anomaly; the hot spot is not making a huge amount of melt, and that melt is modified in coming through the continent, so Yellowstone explodes despite being a hot spot. But most hot-spot volcanoes are not highly explosive. The "protective" layer of condominiums is developing in parts of Hawaii, but lots will happen to the volcanoes in addition—earthquakes and eruptions and drifting and more—and wait until next time when we learn about sides falling off!

The picture shows some rocks on the beach at Olympic National Park. The pocket knife is about 3 inches (or 8 cm) long. What is the story of these rocks? A) The pocket knife washed overboard from a Chinese freighter in a storm, and floated to the beach on the currents; scientists use the distribution of such flotsam and jetsam to learn about the oceanic currents that drive plate tectonics. B) Earthquakes knocked loose undersea muds that raced down the slope into the subduction zone to make these layered rocks, which were scraped off the downgoing slab, part of the process by which continents shrink as the scraped-off material is added to their edges at subduction zones. C) The pocket knife was flushed out of an airline toilet by an absent-minded geologist, and fell on the rock. D) The layering comes from different volcanic eruptions that piled material on the beach, as part of the process by which spreading zones tear apart continents, causing them to become smaller over time. D) Earthquakes knocked loose undersea muds that raced down the slope into the subduction zone to make these layered rocks, which were scraped off the downgoing slab, part of the process by which continents grow as the scraped-off material is added to their edges at subduction zones.

Answer: Earthquakes knocked loose undersea muds that raced down the slope into the subduction zone to make these layered rocks, which were scraped off the downgoing slab, part of the process by which continents grow as the scraped-off material is added to their edges at subduction zones. Olympic is the pile of scraped-off stuff, and some of it fell into the trench rather recently during earthquakes. Build-up of material above subduction zones contributes to growth of continents over time, not shrinkage. There really are volcanic layers, but as described in the slide show, these are not volcanic layers, and continents grow over time rather than shrinking. Things do wash off freighters, and items such as rubber ducks and shoes have been used to trace ocean currents, but pocket knives sink, and ocean currents are not the driving force for drifting plates. Airline toilets flush into holding tanks on the plane, not onto people or rocks below, and very rarely have pocket knives because the knives are confiscated first.

Heat transfer by conduction is: A) Always less efficient than heat transfer by lemmings. B) Inefficient over short and long distances but efficient over intermediate distances. C) Efficient over short distances but inefficient over long distances. D) Efficient over long distances but inefficient over short distances. E) Efficient over short and long distances but inefficient over intermediate distances.

Answer: Efficient over short distances but inefficient over long distances. Touch a hot stove burner and you will soon learn that conduction of heat occurs rapidly over short distances, with no involvement of lemmings whatsoever. Heat one side of a thick potholder, and you'll find that heat conduction through that thickness takes much longer. If you think of heat as how rapidly an atom is vibrating, conduction is a fast atom colliding with a slower neighbor, and speeding it up. Pushing your neighbor to push its neighbor to push its neighbor... is very inefficient over long distances, but pushing your neighbor gets a very quick response over short distances.

The picture above shows the stem of devil's club, a plant of the northwestern coast of North America. The native people use devil's club for medicinal purposes. We now know that: A) Plants protect themselves in many ways, including thorns but also through chemicals that are poisonous to many things that would eat the plants; those chemicals are sometimes harmful to humans (poison ivy, for example) but sometimes beneficial to humans, and have given us many of our medicines. B) Plants protect themselves in many ways, including thorns but also through chemicals that are poisonous to many things that would eat the plants; those chemicals are always harmful to humans (poison ivy, for example). C) Plants protect themselves in many ways, including thorns but also through chemicals that are poisonous to many things that would eat the plants; those chemicals are always beneficial to humans, and are the basis for all of our medicines. D) This is a device developed by Pepsi to keep people away from Coke machines. E) Most plants protect themselves primarily through thorns, hairs, etc., such as shown here.

Answer: Plants protect themselves in many ways, including thorns but also through chemicals that are poisonous to many things that would eat the plants; those chemicals are sometimes harmful to humans (poison ivy, for example) but sometimes beneficial to humans, and have given us many of our medicines. Most plants have physical protections of some sort (hairs, thorns, hardened parts, bark, etc.), but almost all plants have chemical defenses. Those chemical defenses may kill us if we eat too much, but they also may kill microbes that would kill us before the chemicals kill us. A whole lot of our medicines have come from plants, and there undoubtedly are more to be discovered. There is a race on to find those new medicines before we exterminate the plants containing the medicines. Devil's club has been around longer than Pepsi has.

You are asked to assign as accurate a numerical age as possible (how many years old) to a sedimentary deposit. You would be wise to use: A) Counting of annual layers if the deposit is old (more than about 100,000 years), and radiometric techniques if the deposit is young (less than about 100,000 years). B) Either counting of annual layers or uniformitarian techniques if the deposit is old (more than about 100,000 years), and radiometric techniques if the deposit is young (less than about 100,000 years). C) Uniformitarian techniques if the deposit is young (less than 100,000 years), and counting of annual layers if the deposit is old (more than 100,000 years). D) Either counting of annual layers or radiometric techniques if the deposit is young (less than about 100,000 years), and radiometric techniques if the deposit is old (more than about 100,000 years). E) Uniformitarian techniques for very old (billions of years) or young (less than 100,000 years) deposits, and radiometric techniques for ages in-between 100,000 years and a few billion years.

Answer: Either counting of annual layers or radiometric techniques if the deposit is young (less than about 100,000 years), and radiometric techniques if the deposit is old (more than about 100,000 years). If you want an absolute date (number of years) rather than older/younger, you can count layers for young things, or use radiometric techniques for young things or for old ones. Uniformitarian calculations aren't very accurate.

You get in your Magic School Bus, drive down the throat of a volcano, and find that you are driving through melted rock that flows with much greater difficulty than does most melted rock, because the melted rock you are driving through is lumpier than typical for melted rock. It is likely that the melted rock you are driving through is: A) Especially low in water and carbon dioxide compared to most melted rocks. B) Especially warm compared to most melted rocks. C) Especially rich in water and carbon dioxide compared to most melted rocks. D) Especially rich in Diet Pepsi compared to most melted rocks. E) Especially rich in iron and other things that would get between silicon-oxygen tetrahedra, compared to most melted rocks.

Answer: Especially low in water and carbon dioxide compared to most melted rocks. The silicon-oxygen tetrahedra link up to make lumps, so anything that gets in the way of this linking will oppose lumping. Iron, water, carbon dioxide, or high heat that shakes the lumps apart can all oppose the lumping of polymerization. Diet Pepsi would break up lumps, too, although isn't especially likely in melted rock.

In the photo above, Dave and Kym are discussing a model of the Waterpocket Fold in Capitol Reef National Park. The Waterpocket probably formed in the same way as the Front Range of the Rockies.This involved: A) The spreading of Death Valley pinched Utah into Colorado. B) The low region, in Dave's left hand, dropped relative to the high region, in Dave's right hand, along a Death-Valley-type fault, and something similar happened in dropping Denver relative to the Front Range. C) Especially warm sea floor in the subduction zone off the west coast rubbed along under western North America and squeezed or wrinkled the rocks, folding them (probably with a push-together fault somewhat deeper under the fold). D) An obduction zone in western Utah squeezed eastern Utah (Capitol Reef) and Colorado (Front Range). E) A subduction zone in western Utah squeezed eastern Utah (Capitol Reef) and Colorado (Front Range).

Answer: Especially warm sea floor in the subduction zone off the west coast rubbed along under western North America and squeezed or wrinkled the rocks, folding them (probably with a push-together fault somewhat deeper under the fold). We're still arguing about the West, but it is clear that the west-coast subduction zone, which started with old, cold sea floor going down, slowly warmed as the subduction zone and the spreading ridge came closer together. Warmer sea floor would be more buoyant, and so would sink more slowly, or float better. And that would create more friction, squeezing and rumpling with the overlying continent. As the sea floor warmed, squeezed-up/rumpled-up features developed in the West. So we think this makes sense.

Evolution produces new types, and extinction gets rid of them. The scientific evidence summarized in the text and in class shows that: A) Over a typical interval of a few tens of millions of years, evolution exceeds extinction so that biodiversity increases with time. B) Over a typical interval of a few tens of millions of years, extinction exceeds evolution so that biodiversity decreases with time. C) Over short and over long times, extinction and evolution are in balance so that biodiversity remains constant. D) Evolution and extinction are usually more-or-less in balance, but occasional mass extinctions reduce biodiversity, and subsequent evolution faster than extinction increases biodiversity until a new balance is reached. E) Extinction does not occur.

Answer: Evolution and extinction are usually more-or-less in balance, but occasional mass extinctions reduce biodiversity, and subsequent evolution faster than extinction increases biodiversity until a new balance is reached. Numerous extinctions have occurred over the history of the planet, but extinctions have been especially rapid during the short "mass extinctions" including the one that killed the dinosaurs. After mass extinctions, evolution fills the empty niches, increasing biodiversity back to a more-or-less stable level.

Soil is produced by weathering of rocks, and moved to streams by mass-movement. Our understanding of nature and humans shows: A) Naturally, soil thickness reaches an approximate balance, with soil production and loss about equal if averaged over an appropriate time, but human activities have upset this balance and caused soil to thin. B) Naturally, soil thickens over time, and human activities have caused soil to thicken more rapidly than the natural rate. C) Naturally, soil thins over time, and human activities have caused soil to thin more rapidly than the natural rate. D) Naturally, soil was primarily marmot #2, but human pets are now the major source. The soil is mainly produced by human pets. E) Naturally, soil thickness reaches an approximate balance, with soil production and loss about equal if averaged over an appropriate time, but human activities have upset this balance and caused soil to thicken.

Answer: Naturally, soil thickness reaches an approximate balance, with soil production and loss about equal if averaged over an appropriate time, but human activities have upset this balance and caused soil to thin. Naturally, there is a balance between production and removal of soil over large areas and long times, although over short times the thickness may change. Humans have greatly increased loss of soil through burning, plowing, etc., which is not good for our long-term ability to grow crops. Human pets (including orange-and-white Coral and gray Prancer Alley, seen here in a group hug with Eeyore), do affect things but are not major sources of soil.

Soil is produced by weathering of rocks, and moved to streams by mass-movement. Our understanding of nature and humans shows: A) Naturally, soil was primarily marmot #2, but human pets are now the major source. The soil is mainly produced by human pets. B) Naturally, soil thickness reaches an approximate balance, with soil production and loss about equal if averaged over an appropriate time, but human activities have upset this balance and caused soil to thicken. C) Naturally, soil thins over time, and human activities have caused soil to thin more rapidly than the natural rate. D) Naturally, soil thickness reaches an approximate balance, with soil production and loss about equal if averaged over an appropriate time, but human activities have upset this balance and caused soil to thin. E) Naturally, soil thickens over time, and human activities have caused soil to thicken more rapidly than the natural rate.

The final arbitrator between two alternate theories (for example Aristotle's and Newton's ideas) is: A) A committee of "wise men" who gather twice a year to arbitrate such disputes. B) Nature, and experiments conducted to test each idea. C) The Nobel Prize Committee in Stockholm, Sweden. D) A public opinion poll conducted by Gallup, ABC News, and Fox News.

Answer: Nature, and experiments conducted to test each idea. Unlike painting or literature, scientific inquiry has a well-defined procedure for figuring out if Newton's ideas are better or if Aristotle had it right all along. In looking at a painting, we can ask different people what they think, or we can make up our own mind on whether we like it or not, and that is perfectly valid. In science, we have to ask: does the idea fit with the way the world works? Can I predict the speed of a falling object better using Newton's ideas or Aristotle's? As it turns out, Aristotle's ideas didn't predict things very well, and Newton's did.

In the photograph above, a portion of cliff about 30 feet high is shown. From what location in the Grand Canyon did Dr. Alley take this image? A) Near the top, in sedimentary rocks that slumped downhill when they were soft, folding the rocks. B) Near the bottom, where the river has cut through rocks that were cooked, squeezed, and partially melted deep in an old mountain range. C) Near the west end, where lava that came up pull-apart faults folded while flowing before hardening fully. D) About halfway between the top and the river, where a large fault has dragged the rocks and caused the fold. E) In the gift shop, where artists have painted the cliff to look like real rocks.

Answer: Near the bottom, where the river has cut through rocks that were cooked, squeezed, and partially melted deep in an old mountain range. This is the Vishnu Schist and Zoroaster Granite, rocks from the heart of a mountain range. The river is just barely out of the picture to the bottom.

If two drifting continents run into each other: A) The older, colder one will be subducted back into the deep mantle, forming a new subduction zone. B) Neither will be subducted back into the deep mantle; instead, they will form an obduction zone. C) The older, colder one will sink into the core. D) The older, colder one will sink into a giant subterranean lake of Pepsi One. E) Both will be subducted back into the deep mantle, forming a new subduction zone.

Answer: Neither will be subducted back into the deep mantle; instead, they will form an obduction zone. "The Unsinkable North America" might not make it as a vehicle for show tunes, but continents have floated around for 4 billion years and are unlikely to sink in the near future. Old, cold sea floor can sink into the mantle, but continents are lower in density than sea floor and cannot follow. A continent could sink into a subterranean lake of Pepsi One if such a thing existed, but no such thing exists.

Limestone, the type of rock most likely to contain caves, is made up of: A) Rocks that solidified deep beneath a volcano. B) Rocks squeezed and cooked deep in a mountain range. C) Rocks erupted from volcanoes. D) Grains of sand that have weathered out of granite, "glued" together by hard-water deposits. E) Old shells, or pieces of old shells, pressed together.

Answer: Old shells, or pieces of old shells, pressed together. Look closely in the walls of Mammoth Cave, and you'll see the shells of extinct sea creatures. Those shells are embedded in broken -up shell pieces, and things that were grown by algae and other living things in the ocean that you might not call "shell" but that serve the same purposes.

In the map above, blue shows the Mississippi River, and the Gulf of Mexico, around the Birdfoot Delta of the river. The USGS image uses different colors to indicate changes in the delta. Orange and red both indicate change in one direction, whereas yellow and green indicate change in the other direction. Based on the material presented in this class: A) Orange and red indicate loss of wetlands over time, whereas yellow and green indicate gain of wetlands over time. B) Orange and red indicate gain of wetlands over time, whereas yellow and green indicate loss of wetlands over time.

Answer: Orange and red indicate loss of wetlands over time, whereas yellow and green indicate gain of wetlands over time. The Mississippi Delta is sinking below the waves, so the widespread orange and red must indicate loss of wetlands.

Human population continues to grow. Looking at many of the things we use on Earth (farmland and land for wood and other things, fish in the sea, etc.): A) We use almost all of the Diet Pepsi springs but with huge natural reserves of Diet Coke. B) We use less than 1% or so, the tiniest bit, with vast amounts out there in the wilderness somewhere. C) We use almost all of the dilithium crystals for our warp drives. D) Our use is large but not everything; we are approaching use of half of all that is available. E) We use almost everything, 99% or more, so we're in deep doo-doo for the future.

Answer: Our use is large but not everything; we are approaching use of half of all that is available. We have removed perhaps 90% of the large fish in the ocean, and we raise crops or cut trees on much of the land surface. In very round numbers, we are approaching use of half of everything available on the planet, with the likelihood that we will greatly increase our population in the future.

What is accurate about seismic waves moving through the Earth? A) P-waves (also called push-waves or sound waves) move through solids but not liquids. B) P-waves (also called push-waves or sound waves) move through both solids and liquids. C) P-waves (also called push-waves or sound waves) move through liquids but not solids. D) P-waves (also called push-waves or sound waves) move through neither solids nor liquids. E) P-waves (also called push-waves or sound waves) move through solids and all liquids except Diet Pepsi.

Answer: P-waves (also called push-waves or sound waves) move through both solids and liquids. P-waves go through liquids and solids, because you can squeeze and release a liquid or a solid—push here and it squeezes a bit, which squeezes what is next to you... and on in a wave.

Heating of some materials produces coal. With increasing temperature and time, one observes: A) Peat, lignite, anthracite, bituminous. B) Peat, lignite, bituminous, anthracite. C) Anthracite, lignite, bituminous, peat. D) Peat, anthracite, lignite, bituminous. E) Anthracite, bituminous, peat, lignite.

Answer: Peat, lignite, bituminous, anthracite. This is mostly memorization. But the names hide a lot of history, the peat-bog cutters of Ireland, the brown lignites now being mined in Wyoming, the deep-mines and strip-mines of the bituminous coals of western Pennsylvania, West Virginia and elsewhere, and the hard-coal anthracite of the Scranton and Wilkes-Barre region. If you don't know any of this history, you might consider reading up on it a bit; it is fascinating.

The pictures show famous volcanoes, that are discussed in the class materials. Which statement is most accurate about these? A) Picture II shows a pile that a giant marmot named George dug up, and picture I shows a pile made by his good friend Herb. B) Picture II shows a subduction-zone-type stratovolcano, and picture I shows a hot-spot-type shield volcano. C) Picture II shows a throws-small-pieces cinder cone, and picture I shows a head-of-hot-spot flood basalt. D) Picture II shows a hot-spot-type shield volcano, and picture I shows a subduction-zone-type stratovolcano. E) Picture II shows a head-of-hot-spot cinder cone, and picture I shows a subduction-zone-type throws-small-pieces flood basalt.

Answer: Picture II shows a hot-spot-type shield volcano, and picture I shows a subduction-zone-type stratovolcano. Picture I is the glorious stratovolcano Lassen Peak, in the Cascades of northern California, and picture II is the shield volcano of Mauna Loa, on the island of Hawaii.

Scientists promote the teaching of evolutionary theory, in part to raise new scientists to help use evolutionary theory. How are scientists using evolutionary theory in efforts that can help people? A) There is no way that knowledge of evolutionary theory can possibly help anyone. B) Evolutionary theory is being used to understand, and help fight, the emergence of antibiotic-resistant diseases and other new diseases, and even to guide thinking in computer science. C) Evolutionary theory is being used to guide thinking in computer science, but in no other way. D) There is no way that knowledge of evolutionary theory can possibly help anyone other than scientists, but it makes the scientists feel good. E) Evolutionary theory is being used to understand, and help fight, the emergence of antibiotic-resistant diseases, but in no other way.

Answer: Evolutionary theory is being used to understand, and help fight, the emergence of antibiotic-resistant diseases and other new diseases, and even to guide thinking in computer science. As antibiotic resistance appears in disease organisms, evolutionary biologists are helping doctors find better strategies to keep us healthy. The processes behind evolution—try new things, keep the ones that work, repeat—has been used intentionally for guidance in many human endeavors, including "evolutionary computing" in computer science. Ecologists trying to rescue ecosystems are informed by understanding of the evolutionary processes that made, and are changing, those ecosystems. Even regulations for sport fishing are guided by our understanding of evolution. In the same way as other successful ideas in science, evolution is useful in many practical ways in the real world.

What is accurate about humans and extinctions? A) Extinction has always happened naturally, and humans haven't affected it. B) Extinction has always happened naturally, and humans have reduced the rate of extinction. C) Extinction has been caused only by prehistoric humans. D) Extinction has been caused only by modern humans. E) Extinction has always happened naturally, but humans have accelerated the rate of extinction; both early humans and modern humans have contributed to extinction.

Answer: Extinction has always happened naturally, but humans have accelerated the rate of extinction; both early humans and modern humans have contributed to extinction. Extinction has happened naturally, but humans have greatly accelerated the rate. Early humans caused extinctions, and so have modern humans, with real worries that the rate of extinction will accelerate a lot more in the near future.

When humans build or raise levees along big rivers such as the lower part of the Mississippi, we are likely to cause: A) Madonna and Don McLean to drive their Chevys to the levees, but the levees will be dissolving rapidly in Pepsi. B) The surface of the water in the river to become slanted to the side, as mud compaction beneath the river increases meandering. C) Fields and roads on the flood plain to rise above the surface of the river, because compaction of flood-plain mud will no longer be balanced by sediment accumulation during floods. D) Fields and roads on the flood plain to drop below the surface of the river, because compaction of flood-plain mud will no longer be balanced by sediment accumulation during floods. E) Land to emerge from the sea at the mouth of the river, because the levees stop compaction of sediment downstream.

Answer: Fields and roads on the flood plain to drop below the surface of the river, because compaction of flood-plain mud will no longer be balanced by sediment accumulation during floods. "Long, long, time ago, I can still remember how the river used to mend with mud..." The continuing compaction of the sediment along the lower Mississippi should be balanced by new deposits on top; stopping the new deposits does not stop the compaction, so the surface of the flood plain sinks. Even racing around curves, rivers don't tilt much, and mud compaction doesn't do much to meandering. "With a pink carnation and a pickup truck..."

In the picture above, the ice that modified the rock moved: A) From left to right, striating the surfaces the ice reached first and plucking blocks loose from the far sides of bumps. B) From top to bottom; ice flows downhill, and this is the downhill direction. C) From right to left, smashing the front of the rock and then sandpapering the back of the rock smooth. D) From bottom to top; ice often is forced uphill, as seen here. E) Directly from the rock toward the camera.

Answer: From left to right, striating the surfaces the ice reached first and plucking blocks loose from the far sides of bumps. Indeed, ice sandpapers and striates the rocks it hits first, and then plucks blocks loose from the other side. And the striae go in the direction that the ice moved.

As water from rain soaks through the soil, the water typically: A) Loses carbon dioxide (CO2) to the air and then to plant roots, becoming more basic. B) Gains humic compounds from the air and more from the soil, becoming a strong base. C) Gains carbon dioxide (CO2) from the air and then gains more carbon dioxide in the soil, becoming more acidic. D) Neither gains nor loses carbon dioxide (CO2) in the air or the soil. E) Gains Diet Pepsi from the air and loses it in the soil, becoming a strong electrolyte.

Answer: Gains carbon dioxide (CO2) from the air and then gains more carbon dioxide in the soil, becoming more acidic. CO2 is fairly soluble in water. Rain picks up some in the air, becoming slightly acidic. Lots of things living in the soil emit carbon dioxide, and soils contain a lot of carbon dioxide that helps make water more acidic. Humic compounds are picked up from soil by water, and make the water more acidic.

As water from rain soaks through the soil, the water typically: A) Neither gains nor loses carbon dioxide (CO2) in the air or the soil. B) Gains humic compounds from the air and more from the soil, becoming a strong base. C) Loses carbon dioxide (CO2) to the air and then to plant roots, becoming more basic. D) Gains carbon dioxide (CO2) from the air and then gains more carbon dioxide in the soil, becoming more acidic. E) Gains Diet Pepsi from the air and loses it in the soil, becoming a strong electrolyte.

The New Madrid Fault Zone in Missouri has had some surprisingly big earthquakes. A magneto-hydro-astronomer at a small university near the fault zone reports that the gravitational effects of the coming alignment of several planets, together with the weakening of the magnetic field, will cause a giant earthquake on the fault zone on Wednesday morning between 1 and 4 am. Based on materials covered so far in this class, you would be wise to: A) Listen up; although the forecast is not certain, such forecasts are usually fairly accurate and should be heeded. B) Get back to whatever you were doing and ignore the forecast; although there might be a very small effect of planetary gravity or magnetic fields on earthquakes, no one has ever demonstrated the ability to make such detailed forecasts accurately, and many such forecasts have proven to be wrong. C) Go to St. Louis with your camera, to photograph the Gateway Arch when it falls during the quake, because the pictures will be worth a lot of money. D) Invest in soda stocks; people always want cold caffeinated drinks after an earthquake, and an earthquake is highly likely at the time and place predicted. E) Go to California to get your valuable pictures; forecasts of when earthquakes will occur are more accurate than forecasts of where an earthquake will occur, California is more likely to have a quake, so you should be there Wednesday to see the damage from the giant quake.

Answer: Get back to whatever you were doing and ignore the forecast; although there might be a very small effect of planetary gravity or magnetic fields on earthquakes, no one has ever demonstrated the ability to make such detailed forecasts accurately, and many such forecasts have proven to be wrong. By keeping track of where earthquakes happen, combing written and oral histories of past earthquakes, looking at geological deposits to see where shaking has occurred and broken rocks or tree roots or caused sand boils, and measuring where rocks are moving and where they aren't, good estimates can be made of earthquake hazards; but, we can't figure out exactly when the next quake will hit. Planetary-alignment predictions have been made, and have failed miserably. The tiny effect of gravity of the planets on the Earth has not been shown to affect earthquakes at all, although it remains possible that some very small influence exists.

The above image is a satellite picture of Cape Cod. What is most accurate about the past and future of the Cape? A) Glaciers built a pile of sand and gravel where rivers cannot sustain it, and the Cape will be eroded until the hard granite core is exposed, like Acadia. B) Glaciers built a pile of sand and gravel where rivers cannot sustain it, and the Cape eventually will disappear beneath the waves. C) The Cape was built by longshore drift from the Hudson and Connecticut Rivers, and will continue to be nourished in the future. D) Glaciers built a pile of sand and gravel that is sustained by longshore sediment drift from the Hudson and Connecticut Rivers, and the Cape will endure forever. E) The military built the Cape as a "Maginot Line" to stop Russian submarines, and now that the Cold War is over, doesn't need the Cape any more and is taking it apart.

Answer: Glaciers built a pile of sand and gravel where rivers cannot sustain it, and the Cape eventually will disappear beneath the waves. The Cape is an end moraine attached to a medial moraine, built by the glaciers in an unsustainable place, and destined to disappear many millennia in the future.

Most U.S. beaches are shrinking or encroaching on the land rather than growing or moving seaward, so the land of the U.S. is getting smaller, not bigger. Causes include: A) Global sea level fell as the ice-age ice sheets grew, exposing sand to the attack of large waves during winter storms, so beaches are now being removed. B) Global sea level fell as the ice-age ice sheets grew, and this caused rivers to deliver much sediment to the coast. C) Local regions are rising as fluid injection wells used for waste disposal bulge up the land in many places. D) Dams on rivers have increased sediment delivery to the beaches. E) Global sea level is rising, covering more land.

Answer: Global sea level is rising, covering more land. As sea level rises, beaches are pushed landward unless something happens to offset this tendency. Global sea level fell way back in time (from about 110,000 years ago to about 20,000 years ago), but that isn't having much effect on coasts any more. And if the ground were rising from injection wells, then the land would be getting bigger, not smaller.

Sedimentary rocks composed of clasts or chunks are usually subclassified by geologists based on: A) Mode of weathering—rocks made of pieces from chemical weathering and from physical weathering are given different names based on how the original rock was taken apart. B) Chemistry—The iron-bearing ones and the silica-bearing ones and others are separated. C) Color—red rocks and green rocks and fuchsia rocks and other rocks are named based on color. D) Grain size—rocks made of big pieces are given different names than are rocks made of little pieces. E) Ability to dissolve in Coke or Pepsi.

Answer: Grain size—rocks made of big pieces are given different names than are rocks made of little pieces. Small clay pieces make clay or shale, bigger silt pieces make siltstone, still-bigger sand pieces make sandstone, and so on. Almost all rocks contain iron and silica and other things, so the chemical classification doesn't work very well. Color is not often a useful indicator—rock colors change a lot during weathering, and often when oil or water move through. Mode of weathering is of interest, but isn't fundamental for the sedimentary rock.

The glacier shown above: A) Has retreated, because a decrease in snowfall to the accumulation zone (A) or an increase in melting of the ablation zone (B) occurred. B) Has advanced, because a decrease in snowfall to the ablation zone (A) or an increase in melting of the accumulation zone (B) occurred. C) Has retreated, because a decrease in snowfall to the ablation zone (A) or an increase in melting of the accumulation zone (B) occurred. D) Has advanced, because a decrease in snowfall to the accumulation zone (A) or an increase in melting of the ablation zone (B) occurred. E) Has not changed.

Answer: Has retreated, because a decrease in snowfall to the accumulation zone (A) or an increase in melting of the ablation zone (B) occurred. Accumulation is a building up, ablation a wearing away or loss. The glacier builds at high elevation (A) and wears away at low elevation (B). And, the halo of moraine around this glacier at low elevation shows that the ice has retreated, so a decrease in snowfall to the accumulation zone or an increase in melting of the ablation zone is indicated.

Volcanoes in Death Valley: A) Filled the valley with lava during the Ice Age to make a great lake. B) Used to happen, but have all been dead for a geologically very long time (millions of years or more). C) Filled the valley with Diet Pepsi during the Ice Age to make a really funky lake. D) Have erupted recently (within the last centuries or millennia), showing that hot rock occurs at shallow depth beneath the valley. E) Don't occur; the rocks under the valley are not nearly hot enough for volcanism.

Answer: Have erupted recently (within the last centuries or millennia), showing that hot rock occurs at shallow depth beneath the valley. Death Valley, and many of the surrounding parts of Nevada and California, have experienced geologically recent volcanic activity. This is one of the problems facing the plan to put nuclear waste in an underground repository in Nevada and leave that waste—are we sure that a volcano won't erupt through the repository? There has not been enough lava erupted to fill the valley, however, nor do volcanoes erupt Diet Pepsi (although you can make a nice volcano model by quickly popping the top of a hot, shaken can of pop).

Which of the following is part of the evidence that the odd layer marking the extinction of the dinosaurs was caused by a large meteorite impact? A) High concentrations of Pepsi found in the layer. B) High concentrations of potassium-40 found in the layer. C) High concentrations of silica found in the layer. D) High concentrations of argon-40 found in the layer. E) High concentrations of iridium found in the layer.

Answer: High concentrations of iridium found in the layer. We have seen several times that iron and silica are very common, that potassium-40 is also common in many rocks (although it changes to argon-40 with increasing age), and that argon-40 appears from potassium-40 over time and so can be quite common in many older rocks. However, iridium is rare on the surface of the Earth, common in meteorites, and common in the layer.

The pictures labeled I and II show fossils from a sediment core collected from the floor of the Atlantic ocean, east of South Carolina. The sediment has not been disturbed by landslides or mountain building or other processes. The pictures were taken by Brian Huber, of the Smithsonian Institution, using a scanning electron microscope. The two samples in the sediment core were separated by the unique layer marking the extinction that killed the dinosaurs.Which is correct? A) I is older than the unique layer, and thus was bathed in Diet Pepsi on the sea floor. B) II is older than the unique layer, and thus sat below the unique layer in the sediment on the sea floor. C) II is older than the unique layer, and thus sat above the unique layer in the sediment on the sea floor. D) I is older than the unique layer, and thus sat below the unique layer in the sediment on the sea floor.

Answer: I is older than the unique layer, and thus sat below the unique layer in the sediment on the sea floor. Before the impact, biodiversity was high, as shown in I, which includes fossils from below the unique layer and thus deposited before the meteorite hit. After the impact, most of the living types were killed, giving rise to the limited diversity seen in II from above the unique layer after the impact.

A University of Michigan student visiting Penn State's University Park campus drinks too much Diet Pepsi, wanders out in a pouring rainstorm, and takes a leak in a sinkhole behind the nearby Nittany Mall. The trout in the stream to which the sinkhole drains will notice the dastardly deed: A) In a few centuries. B) In a few hours to days. C) Never, because all sinkholes drain to Michigan. D) In a few thousand years. E) Never, because sinkholes don't drain to trout streams.

Answer: In a few hours to days. Sinkholes often connect directly and quickly to underground caves or big cracks, and thus to streams, allowing rapid drainage. There are rock units that would hold their water for centuries or millennia, but such units have small spaces, not caves and sinkholes. Local sinkholes do drain to trout streams, and Michigan has to make their own water pollution because pollution from Pennsylvania does not reach them. (Fun thing to do if you're bored: fit this question into the Michigan fight song.)

What is an important idea that geologists use to put sedimentary rocks in order from older to younger? A) In a normal pile of sedimentary layers, the ages do not show any regular progression from oldest to youngest or youngest to oldest going up through the pile, but instead are randomly distributed. B) In a normal pile of sedimentary layers, the layer on the top and the layer on the bottom are the two oldest layers, and the layer in the middle is the youngest. C) In a normal pile of sedimentary layers, the layer on the bottom is the oldest, and the layer on the top is the youngest. D) In a normal pile of sedimentary layers, the layer on the top was deposited first, then the one beneath it, and so on, with the most recently deposited layer on the bottom. E) In a normal pile of sedimentary layers, all are of exactly the same age.

Answer: In a normal pile of sedimentary layers, the layer on the bottom is the oldest, and the layer on the top is the youngest. A layer of sediment is deposited from wind or water or ice. Then, another is deposited on top—the wind does not reach down, pick up the "carpet" of a layer of dirt or rock beneath, and sweep a new layer underneath it.

The best description of a scientist's job is that she or he: A) Uses the scientific method to learn the Truth. B) Invents new ideas, and shows that some ideas are false. C) Is always sexy. D) Uses only high-tech equipment. E) Invents new ideas, and proves that some ideas are True.

Answer: Invents new ideas, and shows that some ideas are false. Much of the fun in science is coming up with great new ideas (hypotheses, if you like fancy words). But for your new idea to "win", you have to show that it does better than old ideas, so you have to prove those old ideas false (or incomplete, or not-quite-right, or whatever "nice" word you might prefer). The scientific method is a powerful way for humans to learn to do things, and learn what does and doesn't work, but the results of science are always open to improvement, so are not claimed to be Truth, and probably are not Truth. Some scientists still use pencils and look at things, and there are probably a few non-sexy scientists around somewhere.

The Paleozoic: A) Is "old life", the age of shellfish. B) Is "middle life", the age of dinosaurs. C) Is "new life", the age of mammals. D) Is "old life", the age of algae. E) Is "new life", the age of dinosaurs.

Answer: Is "old life", the age of shellfish. Paleo goes with Past, and is old life. The Paleozoic started with the "fast" (over a few million years) emergence of many creatures with shells, which greatly increased the richness of the fossil record because shells are preserved so well.

If you watched a sand grain moved by waves on a beach on the U.S. east coast, you would usually see that most of its motion: A) Is to the north. B) Is to the north in the winter and to the south in the summer. C) Is alternately toward and away from the shore, causing little net change. D) Is from the shore to the sea in the summer, and from the sea to the shore in the winter. E) Is to the south.

Answer: Is alternately toward and away from the shore, causing little net change. A beach sand grain spends most of its time coming in, going out, coming in, going out, and not getting anywhere. A tiny bias exists, such that the in and out will move slightly along the coast, and will cause seasonal changes.

Most commonly, a hot-spot volcano: A) Is andesitic in composition, and shaped like a Pepsi can, with vertical sides below sea level. B) Is basaltic in composition. C) Is richer in silica than andesite. D) Is lower in silica than basalt, more like the mantle from which the hot-spot lava comes. E) Is mostly andesitic in composition.

Answer: Is basaltic in composition. The rising hot rock of hot spots feeds volcanoes. Both sea floor and hot-spot volcanoes come from melting a little of the very-low-silica mantle, pulling out the melt, and freezing it, and so are basaltic (low-silica) volcanoes. Note, though, that a few hotspots (such as Yellowstone) are not basaltic, because the basalt has been altered in getting through the continent. The melt probably started out as something that would make basalt, and indeed, the Yellowstone hot-spot track includes basaltic lavas such as those at the glorious Craters of the Moon National Monument. The hot-spot lavas are runny, and spread easily under the air to make volcanoes with gradual slopes, unlike the steep stratovolcanoes, although the slopes of hot-spot volcanoes are steeper under water because the water cools the lava so rapidly that it can't spread far.

Using only uniformitarian calculations from the thickness of known sedimentary rocks, likely rates at which those rocks accumulated, and features in and under those sedimentary rocks, geologists working two to three hundred years ago estimated that the Earth: A) Is less than about one-hundred-million years old. B) Has been here forever. C) Is about one-hundred-million years old. D) Is 4.6 billion years old. E) Is more than about one-hundred-million years old.

Answer: Is more than about one-hundred-million years old. Radiometric techniques reveal the Earth to be about 4.6 billion years old, but early geologists did not have the sophisticated instruments to measure the trace radioactive elements and their offspring. Working from the rocks, the geologists knew that the age must be in the neighborhood of 100 million years, plus extra time in unconformities and additional extra time in the oldest, metamorphic rocks.

The gas from the Marcellus shale: A) Is produced by "fracking", which heats the rocks greatly to drive the gas to wells. B) Is produced by "fracking", the prehistoric technique of sucking gas out of rocks using a straw, so-named because someone once said "What the frac...". C) Is produced by "fracking", which employs special "diffraction" lenses to separate valuable fossil fuels from the almost-worthless shale. D) Is produced by "fracking", which uses high-pressure water and chemicals to make new "fractures" in the shale that allow the gas to escape to wells. E) Is produced by "fracking", which is an illegal "infraction" against Pennsylvania laws forbidding gas production, so all the "fracking" is done at night.

Answer: Is produced by "fracking", which uses high-pressure water and chemicals to make new "fractures" in the shale that allow the gas to escape to wells. Water containing special chemicals is pressurized in holes bored through the Marcellus Shale, breaking the rocks to make pathways that allow the gas in the rock to escape through the holes to the surface, where it can be sold.

The Precambrian: A) Is the age of trilobites, and occurred just before the Mesozoic. B) Is the age of algae, and occurred just before the Mesozoic. C) Is the age of trilobites, and occurred just before the Paleozoic. D) Is the age of algae, and occurred just before the Paleozoic. E) Refers to any time before Wales joined the United Kingdom.

Answer: Is the age of algae, and occurred just before the Paleozoic. Indeed, "Cambria" is another name for Wales, and the Precambrian did occur before Wales joined the United Kingdom, but the Paleozoic (just younger than the Precambrian), the Mesozoic and most of the Cenozoic also occurred before Wales joined the United Kingdom. "Age of algae" is not a bad name for the Precambrian; trilobites became prominent early in the Paleozoic.

Science professors teach certain theories and not others (Newton's physics, and not Aristotle's, or Darwin's evolution and not Lamarck's). If you were to ask the professors why, a majority would tell you (more or less; not using exactly these words but with this meaning): A) "Hey, I'm the professor, shut up." B) "Lamarck and Aristotle are so right-wing, and you know all of us professors are part of a vast left-wing conspiracy." C) "Nature has repeatedly been asked (through experiment) which is better, and we are teaching the ones that made successful predictions, and not teaching the ones that failed." D) "Lamarck and Aristotle are so left-wing, and you know all of us professors are part of a vast right-wing conspiracy cleverly dressed up to look like a vast left-wing conspiracy." E) "Well, we have to teach something in exchange for all those wads of cash you students pay, and this is more fun."

Answer: "Nature has repeatedly been asked (through experiment) which is better, and we are teaching the ones that made successful predictions, and not teaching the ones that failed." You can be quite confident that the big-picture items in science class have been tested against reality and found to work. There still might be someone in academe who would reply with B (your professors remember a couple of their professors who could have said such a thing) (the technical term for anyone who would reply with the quote in A is "jerk"), but that is pretty rare today.

First, we must calculate how rapidly limestone is being removed from the floor of the valley. Most of the limestone leaving the valley is dissolved in Spring Creek. Later, we will discuss chunks of limestone being rolled, bounced or otherwise carried out of the valley by Spring Creek, although these are rare. There is almost no loss or gain of limestone in the wind, and meteorite falls are VERY rare and can be ignored.About 1 m (just over 3 feet) of rain per year falls on Happy Valley. About two-thirds of this is used by trees and evaporated, and one-third leaves the valley in Spring Creek. That water which leaves in Spring Creek, called runoff, contains a lot of dissolved limestone, which is picked up from the ground. Spring Creek water averages about 0.33 kilograms (0.33 kg) of limestone for each cubic meter (1 m3) of water. (1 kg is 2.2 pounds, and 1 m3 is a cube just over 3 feet on a side), so the limestone in the water weighs 0.33 kg/m3.If Spring Creek collects a layer of water 0.3 m thick from all of Happy Valley each year (0.3 m3 from each square meter or m2), and each cubic meter of Spring Creek water contains 0.32 kg of limestone, then how much limestone is lost from each square meter of Happy Valley each year, on average? (Note that the units are included and calculated properly for you here, but you should understand what was done, and why.) 0.3 m3/m2/yr x 0.32 kg/m3 = __________ kg/m2/yr. A) .36 B) .0096 C) .036 D) .096 E) .96

Answer: .096 Feedback: You just need to multiply 0.3 by 0.32 on your calculator. The units are there to help you understand, but you don't need them for the answer.

The answer from question 2 shows that the rock lost from each three foot by three foot plot of land in Happy Valley each year weighs a bit less than a small hamburger patty. But, how thick is the layer of rock that is lost each year? We need the density of the rock to calculate the thickness lost. The density of calcite, the main mineral in limestone, is about 2700 kilograms per cubic meter (2700 kg/m3), which is almost three tons for each three foot cube. (Rock is heavy!). There is a tiny bit of space between some of the grains in the rock, so let's use 2550 kilograms per cubic meter (2550 kg/m3) for the density. For simplicity, let's round off the answer from question 2, to obtain one-tenth of a kilogram from each square meter each year, or 0.1 kg/m2/yr (that is 0.22 pounds or 3.5 ounces, which is a bit less than the 4 ounces in a hamburger patty). Dividing this yearly rate at which each square meter of the valley is losing kilograms of rock by the density in kilograms per cubic meter yields the rate at which the valley surface is being lowered in meters per year (m/yr). The lowering rate is 0.1 kg/m2/yr divided by 2550 kg/m3 =____________m/yr (note: your calculator probably shows a whole bunch of digits; just choose the answer below that is closest). A) 0.39 (your calculator might also show this as 3.9x10-1 or something similar) B) 0.09 (your calculator might also show this as 9.0x10-2 or something similar) C) 0.000019 (your calculator might also show this as 1.9x10-5 or something similar) D) 0.000039 (your calculator might also show this as 3.9x10-5 or something similar) E) 0.0039 (your calculator might also show this as 3.9x10-3 or something similar)

Answer: 0.000039 (your calculator might also show this as 3.9x10-5 or something similar) You just need to divide 0.1 by 2550 on your calculator and read the answer. We know that calculator use is usually taught about third grade, so we really hope you are following the logic of this exercise as well as punching in the numbers; otherwise, it is just busy-work!

At its deepest, Happy Valley is close to 330 m (a bit over 1000 feet) deep, and it once was at least as high as the mountains around the valley. Let us call the thickness of rock removed from the valley each year, your answer in the previous blank, 0.00003 m. Then the depth of the valley, 330 m, divided by the erosion rate, 0.00003 m/yr, yields the number of years it took to hollow out Happy Valley, __________yr. This should be a large number. A) 110 B) 110,000 C) 1,100,000,000 D) 11,000 E) 11,000,000

Answer: 11,000,000 This required punching 330, then the division key, then 0.00003, then equals. You're almost done punching buttons on the calculator. Note that 11 million years is a lot of years. If something in your mind says "That's impossible", go back and follow the logic again before going to the next question and trying to get a younger age.

You start with 200 parent atoms of a particular radioactive type, which decays in a single step to give a stable offspring, and you start with none of those stable offspring. You wait just long enough for two half lives to pass. You should expect to have how many offspring atoms (on average)(remember that the number of parents and the number of offspring add up to 200, so if you have 10 parents, you have 190 offspring because 10 and 190 add up to 200, and if you have 20 parents you have 180 offspring, and so on): 200. 50. 100. 150. 25.

Answer: 150 After one half-life, you've gone from 200 parents to 100, and 100 offspring have been made. In the second half-life, you go from 100 to 50 parents, and that makes another 50 offspring. Adding the additional 50 to the 100 from the previous half-life gives 150 offspring. (Typical studies of radioactive decay use many more atoms, to avoid statistical fluctuations, but the question says "on average", so we asked you about 200 rather than 200,000,000,000,000 to make the math easier.)

Both of the above pictures are along the Colorado River. The clear water of picture 1 and the muddy water of picture 2 appear quite different.What's going on? A) 1 is upstream of the Glen Canyon Dam, and 2 is also upstream of the dam. B) 1 is upstream of the Glen Canyon Dam, and 2 is downstream. C) 1 is 7-UP, and 2 is Yoo-Hoo. D) 2 is upstream of the Glen Canyon Dam, and 1 is downstream of the dam. E) 2 is downstream of the Glen Canyon Dam, and 1 is also downstream of the dam.

Answer: 2 is upstream of the Glen Canyon Dam, and 1 is downstream of the dam. The naturally muddy river is seen clearly in Canyonlands in 2. The river dumps its sedimentary load in the reservoir above the dam, so downstream of the dam the water is clear, as shown in 1.

Evidence that glaciers were much bigger about 20,000 years ago than they are now includes: A) Shells of creatures that lived in the ocean about 20,000 years ago indicate that the ocean water was especially isotopically light then. B) 20,000-year-old deceased shallow-water corals occur in growth position far below the surface on the sides of oceanic islands. C) Global sea level today is falling as the water from the melted ice is returned to the oceans. D) Sea level is lower now than it was then, as shown by there being no flooded river valleys anywhere today. E) Land bearing the unique marks of glaciers is sinking today, while regions just around that land are rising as deep hot rock flows back after being displaced by the glaciers.

Answer: 20,000-year-old deceased shallow-water corals occur in growth position far below the surface on the sides of oceanic islands. The land with the unique glacier marks was pushed down by the ice and now is bobbing back up, water returned to the oceans from the melting ice causes sea level to rise rather than to fall, and taking light water out of the oceans to grow ice sheets causes the remaining waters, and the shells, to be isotopically heavy. But, the dead corals in growth position down the sides of islands are evidence for the ice age.

The great diversification of shelly fossils that marks the beginning of the Paleozoic Era occurred about: A) 57,000,000 years ago. B) 5,700,000,000 years ago. C) 57,000 years ago. D) 5,700,000 years ago. E) 570,000,000 years ago.

Answer: 570,000,000 years ago. Humans were trotting around 57,000 years ago. 570,000 years is barely enough time for evolution to have changed large animals a bit, and although 5,700,000 years is enough time for noticeable change of large animals—increase in maximum size of members of the horse family, for example—the huge changes since the dinosaurs needed a bit more than 57,000,000 years (dinosaur extinction was about 65,000,000 years ago). The Paleozoic came before that, and 570,000,000 years is about right. 5,700,000,000 years is more than the age of the Earth, and so doesn't work very well.

Calcium released by chemical weathering is transported by streams to the ocean, where much of it: A) Builds up in the water, making the ocean saltier B) Is subducted back into the mantle at the mid-ocean ridges C) Is extracted from the water by marine dairy cows to add to milk D) Evaporates from the ocean and rains back out on the land E) Is used by clams, corals, etc. to make their shells

Answer: Is used by clams, corals, etc. to make their shells Most common shells seen at the beach are calcium carbonate, and the calcium is provided by weathering of rocks on land. Calcium ions do not evaporate easily, and are not very common in the atmosphere. A little bit of sea salt, and anything else small in the sea, does escape in spray (stand by the sea on a windy day and you'll get spots on your sunglasses), but most of the calcium reaching the sea is used there. The "saltiness" of the ocean is a quite different chemical, not calcium. Some shells are subducted, many more are scraped off downgoing slabs at subduction zones, but subduction does not occur at mid-ocean ridges, which is where sea floor is made, not where sea floor is consumed. Calcium in milk is a good thing, and helps build strong bones and teeth, but dairy cows rarely go to the beach to go swimming, and wouldn't enjoy drinking the water to get their calcium. There is a little bit of calcium in grasses, and cows get some of their calcium from there.

Silica released by chemical weathering is transported by streams to the ocean, where much of it: A) Builds up in the water, making the ocean saltier B) Reacts with hot sea-floor rocks to make different minerals there C) Is subducted back into the mantle at the mid-ocean ridges D) Is extracted from the water by marine dairy cows to add to milk E) Is used by sea creatures to make their shells

Answer: Is used by sea creatures to make their shells Diatoms, radiolarians, and some sponges are among the creatures that make silica shells, from the silica provided by weathering of rocks on land. Silicate ions do not evaporate easily, and are not very common in the atmosphere. A little bit of sea salt, and anything else small in the sea, does escape in spray (stand by the sea on a windy day and you'll get sponts on your sunglasses), but most of the silica reaching the sea is used there. The "saltiness" of the ocean is a quite different chemical, not silica. Some shells are subducted, many more are scraped off downgoing slabs at subduction zones, but subduction does not occur at mid-ocean ridges, which is where sea floor is made, not where sea floor is consumed. Silica is not a major ingredient of milk, although a little silica in some grasses can cause a lot of tooth wear.

What happens to most of the water that falls on central Pennsylvania's Happy Valley each year (or any similar place, such as Washington, DC or other places with trees)? A) It is re-evaporated, mostly after passing through trees. B) It soaks into the ground and then flows to streams. C) It is used in soft-drink bottling plants. D) It flows directly over the surface into streams. E) It falls directly onto streams.

Answer: It is re-evaporated, mostly after passing through trees. Water gives life, and life is very good at using water. When their leaves are out, trees use almost all the rain that falls, and tree roots reach down into the ground and pull up some of the water from cold-season rain and snowmelt. An important amount of water does soak into the ground and flow to streams, but plants still get the majority. Flow across the surface is increasing as we pave the landscape, but most of the land is not paved, and flow across natural surfaces to streams is small. Streams are tiny, so direct rainfall into them is small. And soft-drink plants use only a tiny bit of water compared to total rainfall.

The above picture is from the Escalante-Grand Staircase National Monument. The pink arrows point along some interesting features.What are they? A) Push-together faults, where rocks were moved in earthquakes. B) Unconformities, formed by erosion in the past. C) Mud cracks, formed when a flash flood roared down the road (which is under the lower-right pink arrow), spread mud onto the desert surface, and then the mud dried. D) Joints, formed when the sedimentary rocks were broken by physical-weathering or other processes. E) Pull-apart faults, where rocks were moved in earthquakes.

Answer: Joints, formed when the sedimentary rocks were broken by physical-weathering or other processes. This is the Navajo Sandstone, and it is a sand-dune deposit, but you can't really see that in this picture. Almost all rocks have joints. Joints channel water, and make space for roots, so plants often grow along joints, as you see here. The change from red to white along the upper-left arrow is probably a record of places in the past where fluids carrying oil met fluids carrying water—the water rusted the iron and made red; the oil left the iron reduced and carried it away.

The correct answer to question 4 indicates a lot of years. Could we have really screwed up the calculation, so it is way off? Well, suppose that for all of history until yesterday, Happy Valley was as wet as the wettest places on Earth. (Making central Pennsylvania that wet is almost impossible, because the wettest places on the planet have climatic characteristics that are not possible in Happy Valley. But, just suppose.) Then, the stream would have been carrying rock away faster than we calculated above. In addition, suppose that lots and lots of limestone from Happy Valley has been carried away as chunks in the stream, again meaning that rock has been removed faster than we calculated. (There is almost certainly a grain of truth to this one, but not a lot; observing Spring Creek shows that most of the rocks in transport are actually originate in the mountains--the valley rocks mostly dissolve, and the mountain rocks wash down. But, just suppose.) Call the time to hollow out the valley, from question 4, an even 10,000,000 (10 million) years. Now, if the rock was actually removed 12 times faster than used in that calculation (about as much faster as is possible with what we just told you), what would the new estimate of the time to hollow out the valley using this new, faster rate be? ________yr (your calculator may not show exactly what is listed below; if not, take the one that is closest). (If you're not sure how to proceed, ask yourself this question: if you dig faster, does it take a longer or shorter amount of time to reach the bottom?) A) 120,000,000 B) 8,333 C) 12,000 D) 833,333 E) 1,200

Answer: 833,333 10 million divided by 12 gets you a bit over 800 thousand years, not much less than 1 million, still a lot of years.

You put some atoms together, and they share or trade some electrons. What just happened was: A) A quark reaction. B) A proton reaction. C) A neutron reaction. D) A parton reaction. E) A chemical reaction.

Answer: A chemical reaction. The clouds of electrons around the nuclei of atoms serve as the Velcro of the universe. Atoms gain or lose electrons and then stick together by static electricity, or else share electrons and stick together inside the shared cloud. The nuclei with their protons and neutrons (which are themselves composed of quarks, which also were called partons at one time) are the things held together by the electronic Velcro of chemistry.

The bowl-shaped feature in the foreground of the above photo is: A) A sinkhole, dissolved into the layered basalts, from the breakup that formed the Atlantic, by acidic groundwaters melted from the base of the ice by the Earth's heat. B) A cirque, a bowl gnawed into a mountain at the head of a glacier. C) A moraine, bulldozed up around a glacier that flowed away from the camera. D) A giant alien toilet, proof that we are visited by beings from another planet, but only evident from the air such as seen here. E) A blockfield, which moved downhill under gravity in the cold, permafrost conditions that are evident from the snow in the picture.

Answer: A cirque, a bowl gnawed into a mountain at the head of a glacier. This is indeed a cirque. The strong layering of the rock material is suggestive of bedrock, not loose pieces as seen in moraines and blockfields. This is basaltic bedrock from the breakup that formed the Atlantic, but basaltic bedrock does not dissolve easily in acidic groundwater. And whoooo, what would the alien use for TP???

The bowl-shaped feature in the foreground of the above photo is: A) A sinkhole, dissolved into the layered basalts, from the breakup that formed the Atlantic, by acidic groundwaters melted from the base of the ice by the Earth's heat. B) A giant alien toilet, proof that we are visited by beings from another planet, but only evident from the air such as seen here. C) A blockfield, which moved downhill under gravity in the cold, permafrost conditions that are evident from the snow in the picture. D) A moraine, bulldozed up around a glacier that flowed away from the camera. E) A cirque, a bowl gnawed into a mountain at the head of a glacier.

The above picture shows: A) A glacier, which is generally flowing toward you, carrying rocks picked up from the ridges; the yellow arrow points up one of the stripes of rock, and you can follow the stripe to the ridge where the rocks started. B) A glacier, which is generally flowing away from you, carrying rocks to smear them against the ridges as the glacier makes the mountains bigger; you can see where the black stripe under the yellow arrow curves around to smash against the rock. C) A glacier, which has quit flowing and is wasting away in response to global warming. D) A permafrost soil-creep lobe, which is generally coming toward you, moving in the opposite direction indicated by the arrow. E) A permafrost soil-creep lobe, which is generally moving away from you, moving in the direction indicated by the arrow.

Answer: A glacier, which is generally flowing toward you, carrying rocks picked up from the ridges; the yellow arrow points up one of the stripes of rock, and you can follow the stripe to the ridge where the rocks started. The glacier picks up rocks from ridges, and carries those rocks along to eventually dump those rocks in moraines. The ice is flowing down its surface slope toward you.

What is indicated by the yellow lines in the image above, which separate flat-lying sedimentary rocks, on top, from slanting sedimentary rocks beneath? A) A great fault, where push-together action shoved the upper rocks over the lower ones. B) An intrusion, with melted rocks squirted along the yellow line and then hardened. C) A great unconformity, with sedimentary rocks above resting on metamorphic rocks below. D) A great fault, where pull-apart action slid the upper rocks across the lower ones. E) A great unconformity, with sedimentary rocks above resting on older sedimentary rocks below.

Answer: A great unconformity, with sedimentary rocks above resting on older sedimentary rocks below. John Wesley Powell, of the United States Geological Survey, and the leader of the first boat trip through the Grand Canyon, called the feature marked by the yellow lines "The Great Unconformity". It separates horizontal Paleozoic sedimentary rocks, above, from inclined Precambrian sedimentary rocks, below.

What is indicated by the yellow lines in the image above? A) A great fault, where pull-apart action slid the upper rocks across the lower ones. B) An intrusion, with melted rocks squirted along the yellow line and then hardened. C) A great unconformity, with sedimentary rocks above resting on older sedimentary rocks below. D) A great fault, where push-together action shoved the upper rocks over the lower ones. E) A great unconformity, with sedimentary rocks above resting on metamorphic rocks below.

Look at the picture above. What happened here? A) A great volcanic explosion occurred, spreading material across the landscape, and the hole left behind after the eruption later filled with water. B) Death-Valley-type faulting dropped the bottom, making space for the lake; during the Ice Age, Death Valley looked like this, too. C) A sharp bend in a river created a whirlpool that carved the hole now filled by a lake. D) A giant glacier used to sit here, and water flowing into a hole on the surface fell to the bed and hollowed out a great pothole, seen here. E) An immense marmot named George, shown here, dug the hole.

Answer: A great volcanic explosion occurred, spreading material across the landscape, and the hole left behind after the eruption later filled with water. Nature has many ways to make holes, and many other ways to make mountains. Part of this class is learning to read the clues, just as geologists do. We saw at Death Valley that the faults tend to make straight lines. Streams on glaciers are not nearly this big, nor are river bends. And while George is cute, he could never dig such a hole.

Geological evidence based on several radiometric techniques has provided a scientifically well-accepted age for the Earth. Represent that age of the Earth as the 100-yard length of a football field, and any time interval can be represented as some distance on the field. (So something that lasted one-tenth of the age of the Earth would be ten yards, and something that lasted one-half of the age of the Earth would be fifty yards.) On this scale, the time from when dinosaur extinction made space for large mammals, until today, would be represented by how far on the football field? A little over 1 yard. Over 80 yards. Over 90 yards. 50 yards. 60 yards.

Answer: A little over 1 yard. If the 4.6 billion years of Earth history are 100 yards, then the 65 million years since the dinosaur extinction are a little under 1.5 yards, hence a bit over 1 yard.

The ridge left behind by a glacier that outlines where the glacier had been is called: A) A cirque, composed of till (which is sorted) and outwash (which is unsorted). B) A moraine, composed of till (which is unsorted) and outwash (which is sorted). C) A moraine, composed of till (which is sorted) and outwash (which is unsorted). D) An arête, composed of till (which is unsorted) and outwash (which is sorted). E) A horn, composed of till (which is unsorted) and outwash (which is sorted).

Answer: A moraine, composed of till (which is unsorted) and outwash (which is sorted). The beautiful moraines of Cape Cod, Long Island, Moraine State Park in Pennsylvania, Kettle Moraine State Park in Wisconsin, and elsewhere include unsorted till and sorted outwash.

The above picture is from the Escalante-Grand Staircase National Monument. The pink arrows point along some interesting features.What are they? A) Sand-dune cross beds, formed when the wind deposited sand. B) Mud cracks, formed when a flash flood roared down the road (which is under the lower-right pink arrow), spread mud onto the desert surface, and then the mud dried. C) Joints, formed when the sedimentary rocks were broken by physical-weathering or other processes. D) Unconformities, formed by erosion in the past. E) Faults, where rocks were moved in earthquakes.

Most U.S. beaches are shrinking or encroaching on the land rather than growing or moving seaward, so the land of the U.S. is getting smaller, not bigger. Which of the following is a likely cause for loss of at least some of our beaches: A) Global sea level is falling, exposing more land. B) Land is sinking in some places as it recovers from being bulged up beyond the edge of the ice-age ice sheets. C) Sea-level rise as the last ice age drained river valleys to get rid of bays, and sediment now is transported to the coast rather than being trapped in bays. D) Water, oil and gas are being pumped into the ground in some places, causing the land to rise. E) Dams have greatly increased the sediment supply to deltas that feed longshore drift to grow beaches.

Answer: Land is sinking in some places as it recovers from being bulged up beyond the edge of the ice-age ice sheets. As sea level rises, beaches are pushed landward unless something happens to offset this tendency. Dams keep sediment away from beaches, as do the bays formed by post-glacial sea-level rise, and human-caused subsidence of the land is an important problem. But land rising would make for more land, not less.

When we speak of the Mississippi Delta, most people mean some interesting region in Louisiana with good music and seafood. Geologically, however, the Mississippi Delta is: A) A small trench eroded by the Mississippi River from near Baton Rouge, Louisiana to the Gulf of Mexico. B) A great trench eroded by the Mississippi River from near St. Louis, Missouri to the Gulf of Mexico, causing earthquakes to occur at the tip of this trench near St. Louis, Missouri. C) A river-built deposit that is almost a mile thick at its thickest point, and extends from near Baton Rouge, Louisiana to the Gulf of Mexico. D) A giant pile of spit-up Yoo Hoo. E) A river-built deposit that is several miles thick at its thickest point, and extends from near St. Louis, Missouri to the Gulf of Mexico.

Answer: A river-built deposit that is several miles thick at its thickest point, and extends from near St. Louis, Missouri to the Gulf of Mexico. Amazing as it may seem, the Mississippi has been taking the debris from the vast area from the Rockies to the Appalachians, and dumping that debris into the Gulf of Mexico, building a pile of sediment that is miles thick in places and extends from St. Louis to the Gulf. The mud has filled an old crack in the continent from when the Atlantic and Gulf of Mexico opened, but the mud doesn't stop the earthquakes that occasionally occur near the tip of the crack. And as for the Yoo Hoo, Yuck!

Look at the picture above which shows a region just less than a foot across, of a stream deposit from the base of the same pile of rocks that show up in Bryce Canyon. This picture was taken in the face of a cliff in Red Canyon, just west of Bryce Canyon National Park. A indicates a piece of limestone that has been rounded off in a stream; B indicates a mass of sand glued together by hard-water deposits, and C indicates another such mass of sand glued together by hard-water deposits. In order of time of formation, they are: A) C was glued together by hard-water deposits, then B was glued together by hard-water deposits, then A was formed. B) C was glued together by hard-water deposits, then A was formed, then B was glued together by hard-water deposits. C) B was glued together by hard-water deposits, then C was glued together by hard-water deposits, then A was formed. D) B was glued together by hard-water deposits, then A was formed, then C was glued together by hard-water deposits. E) A was formed first, then B was glued together by hard-water deposits, then C was glued together by hard-water deposits.

Answer: A was formed first, then B was glued together by hard-water deposits, then C was glued together by hard-water deposits. The clast A existed before it was included in a conglomerate glued together by the sand and hard-water deposits of B, so A is older than B; the whole reddish clast containing A and B is glued into another conglomerate by the sand and hard-water deposits of C, so C is youngest of these three.

What is accurate about the scientific results learned by counting annual layers in ice cores? A) Many tests show that some ice cores have reliably preserved annual layers, and the longest record extends back more than 100,000 years. B) Annual layers in ice cores show that the Earth is exactly 12,429 years old. C) Many tests show that the ice cores can't be very old because the ice age melted all the glaciers. D) Many tests show that annual layers exist in ice cores, but only back to 5,000 years, with no older ice. E) There are no annual layers in ice cores, so no one can count them.

Answer: Many tests show that some ice cores have reliably preserved annual layers, and the longest record extends back more than 100,000 years. As detailed in the text, ice-core layer counters do a huge amount of testing to be sure that the layers really represent years, and that the counting is as accurate as possible. The longest such record now extends beyond 100,000 years.

Oxygen (O2) and nitrogen (N2) do not have much greenhouse effect, but several trace gases including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and various chlorofluorocarbons are important greenhouse gases. The primary mechanism by which these greenhouse gases warm the Earth is: A) Preventing convection currents that take heat aloft, in the same way that the glass of a greenhouse stops convection currents and so makes the air in the greenhouse warmer. B) Making politicians mad, so they give speeches that heat the air. C) Raising the atmospheric pressure, because squeezing air warms it, as we saw at the Redwoods. D) Absorbing some of the infrared radiation emitted from the Earth. E) Experiencing chemical reactions with each other, which release energy.

Answer: Absorbing some of the infrared radiation emitted from the Earth. Although it is true that squeezing air warms it, the pressure does not set the temperature (change in pressure brings change in temperature), and, the greenhouse gases are really very rare and don't affect pressure much. The production and breakdown of the greenhouse gases roughly balance energetically, and any slight imbalances are tiny compared to the radiative effects of the gases. Convection currents are blocked by the glass of greenhouses, but not by greenhouse gases. But CO2 does absorb some of the infrared radiation emitted from the planet. Absorbing an infrared photon puts a CO2 molecule into an excited state, and fairly quickly the molecule returns to its unexcited state by emitting a photon of the same energy. Some of those photons emitted by excited CO2 molecules head back toward Earth (the emission direction is random). So, the CO2 serves to trap energy in the Earth system, warming the planet so that it glows more brightly to shove infrared radiation past the CO2, achieving a new balance.

Air moves in from the Pacific, over the Sierra Nevada (a mountain range), and down towards Death Valley. What happens? A) Air moving down the east slope toward Death Valley expands and rains, cooling about 3 degrees F per thousand feet downward. B) Air moving down the east slope toward Death Valley is compressed, and warms by about 5 degrees F per thousand feet downward. C) Air moving down the east slope toward Death Valley expands, rains, and warms by about 5 degrees F per thousand feet downward. D) Air moving down the east slope toward Death Valley is compressed and rains, warming about 3 degrees F per thousand feet downward. E) Air moving down the east slope toward Death Valley is compressed, causing it to dump Diet Pepsi on unwary hikers.

Answer: Air moving down the east slope toward Death Valley is compressed, and warms by about 5 degrees F per thousand feet downward. As the air moves down, it is compressed and warms, by about 5 degrees F per thousand feet downward.

What is accurate about the planet's climate system? A) Much more energy is received from the sun than is sent back to space, because high-energy shortwave radiation is received but low-energy longwave radiation is sent back. B) Almost the same amount of energy is received from the sun as is sent back to space, but shortwave radiation is received and longwave radiation is sent back to space. C) Almost the same amount of energy is received from the sun as is sent back to space, but longwave radiation is received and only energy stored by evaporation is sent back to space. D) Much more energy is received from the sun than is sent back to space, because high-energy longwave radiation is received but low-energy shortwave radiation is sent back. E) Much more energy is sent back to space than is received from the sun, because the planet emits longwave radiation but the sun emits shortwave.

Answer: Almost the same amount of energy is received from the sun as is sent back to space, but shortwave radiation is received and longwave radiation is sent back to space. Energy in equals energy out, to very close approximation. We actually send back the tiniest bit more, because the Earth makes a little energy radioactively and because we are mining stored energy (fossil fuels) and burning it, and some of that goes to heat the atmosphere but some is lost to space. But, these differences are tiny tiny tiny. (Lie in the sun on the grass on a hot day, and see if you can tell whether the sun or the Earth is supplying the most heat to your skin...). We receive shortwave—visible light—and send back longwave—infrared.

Suppose that tomorrow someone bulldozed all the rocks in the Appalachians, right down to sea level, and shipped all of those bulldozed rocks to Uzbekistan to build ski slopes. A few thousand years from now, we probably would find that the surface of the Earth exposed by the bulldozers was: A) As high as the Appalachians are today, because of obduction. B) Higher than the Appalachians are today, because of volcanic eruptions triggered by the bulldozers. C) Almost, but not quite, as high as the Appalachians are today, because the roots of the mountains bobbed up. D) As high as the Appalachians are today, because the roots of the mountains bobbed up. E) At sea level.

Answer: Almost, but not quite, as high as the Appalachians are today, because the roots of the mountains bobbed up. Nine-tenths of an iceberg, or an ice cube, is below water, with one-tenth above. The iceberg is big, the ice cube little, and one-tenth of big is more than one-tenth of little, so the iceberg sticks up higher than the ice cube. Cut the top off the iceberg, let it bob up, cut the top off, let it bob up, and you're slowly turning the berg into a cube, so each time the height of the berg is reduced a little. Same is true for a mountain range—cut the top off by erosion, bobs up almost as high as before, erode the top off, repeat, and slowly the height is reduced. The initial thickness was made by the collision of obduction, but then erosion and bobbing-up take over.

Chemists recognize many different elements, such as gold, or oxygen, or carbon. Suppose you got some carbon, and started splitting it into smaller pieces. The smallest piece that would still be called "carbon" would be: A) A proton B) An electron C) A neutron D) An atom E) A quark

Answer: An atom We can break matter down into atoms (Greek for "not cuttable" because the Greeks didn't have atom smashers or other exotic tools that would allow cutting atoms into smaller pieces). All of the wrong answers here are smaller pieces of atoms, but they wouldn't be gold any more; you can make any of the elements out of these pieces.

In the picture above, a much younger Dr. Alley is shown in the lower left of the picture, next to a muddy tree near Mt. St. Helens. Between Dr. Alley and the people on the right of the picture is the foundation of what used to be a house. What happened here? A) Poisonous gases from the volcano killed the people in the house, and dissolved the glue that held the siding on, so the house fell down. B) The searing blast from the volcano hugged the ground, shot down the mountain, blasted the house away and plastered the tree. C) Bart Simpson blew up the house as part of a science-fair experiment. D) Melted ice from the volcano fed a huge mud flow that thundered down the river valley, washing the house away and plastering mud on the tree trunk. E) Giant rocks thrown by the volcano fell on the house and collapsed it.

Answer: Melted ice from the volcano fed a huge mud flow that thundered down the river valley, washing the house away and plastering mud on the tree trunk. Searing blasts, poison gases, and giant rocks are all volcanic hazards, but a searing blast would have seared the trees, houses do not dissolve in poison gases, and had giant rocks fallen, you would see the rocks. The great flood down the Toutle River did this, supplied by melting ice and by water pushed out of Spirit Lake when the landslide went into the lake. And Bart Simpson had nothing to do with it.

What sort of rock is the dark material very close to the pink granitethat Dr. Alley is pointing to in the picture above? A) Metamorphic; The rock separated into layers as it was cooked and squeezed deep in a mountain range. B) Sediment that isn't rock yet. The layers are alternating silt and sand from deposition from landslides off the Olympic Peninsula into the trench offshore. C) Sedimentary; The layering was caused by changes in the flow velocity of the river that deposited the material D) Marmot #2 E) Igneous; The layers were caused by flow processes during the eruption that released this.

The picture above shows the stem of devil's club, a plant of the northwestern coast of North America.The native people use devil's club for medicinal purposes.We now know that: A) This is a device developed by Pepsi to keep people away from Coke machines. B) Plants protect themselves in many ways, including thorns but also through chemicals that are poisonous to many things that would eat the plants; those chemicals are always beneficial to humans, and are the basis for all of our medicines. C) Most plants protect themselves primarily through thorns, hairs, etc., such as shown here. D) Plants protect themselves in many ways, including thorns but also through chemicals that are poisonous to many things that would eat the plants; those chemicals are always harmful to humans (poison ivy, for example). E) Plants protect themselves in many ways, including thorns but also through chemicals that are poisonous to many things that would eat the plants; those chemicals are sometimes harmful to humans (poison ivy, for example) but sometimes beneficial to humans, and have given us many of our medicines.

The above photograph was taken in the Grand Canyon, and shows a cliff that is approximately 30 feet high.What are the rocks in the cliff? A) Precambrian metamorphic rocks with some igneous rocks intruded; the folding was caused by mountain-building processes when the rocks were very hot deep in a mountain range. B) Cement poured to make the walls of the new gift shop that sits above the canyon, painted to look like something more interesting. C) Recent lava flows from pull-apart faults near the west end of the canyon; the folding happened as the lava cascaded over the canyon walls and flowed toward the river. D) Precambrian sedimentary rocks, preserved in blocks dropped down by Death-Valley-Type faulting; the folding was caused by the drag along the faults. E) Paleozoic sedimentary rocks that form the main walls of the canyon; the folding was caused by mass-movement processes before the rocks were hardened by hard-water deposits.

Answer: Precambrian metamorphic rocks with some igneous rocks intruded; the folding was caused by mountain-building processes when the rocks were very hot deep in a mountain range. This is the Vishnu Schist and Zoroaster Granite, rocks from the heart of a mountain range. The river is just barely out of the picture to the bottom.

The geologic time scale is, starting with the oldest and ending with the youngest: A) Paleozoic, Precambrian, Cenozoic, Mesozoic. B) Precambrian, Paleozoic, Mesozoic, Cenozoic. C) Precambrian, Cenozoic, Mesozoic, Paleozoic. D) Precambrian, Paleozoic, Cenozoic, Mesozoic. E) Paleozoic, Mesozoic, Cenozoic, Precambrian.

Answer: Precambrian, Paleozoic, Mesozoic, Cenozoic. You could probably reason this out if you remember some Greek roots, or else just memorize it—Precambrian is oldest, then Paleozoic, Mesozoic and Cenozoic.

The picture above shows a fault in a place where mountains come down near the coast.What likely happened to form the ramp (also called a scarp) behind the person? A) Slide-past forces shoved one side up over the other, making the break. B) Slide-past forces pulled the rocks apart, making the break, and allowing one side to drop relative to the other. C) Pull-apart forces pulled the rocks apart, making the break, and allowing one side to drop relative to the other. D) Pull-apart forces shoved one side up over the other, making the break. E) An earthquake agitated a great underground lake of Pepsi until "kablam" the top blew off, making this feature.

Answer: Pull-apart forces pulled the rocks apart, making the break, and allowing one side to drop relative to the other. The down-side dropped along the ramp compared to the up-side. (This is actually an interesting one; it formed in Alaska during the 1964 earthquake. That was a push-together quake, but it was so huge and moved so much rock in different directions that some of the rock ended up having pull-apart motions, such as this one.)

This is a photo of a road cut through a mountain called Sideling Hill, in Western Maryland.What happened here? A) Bulldozers bent the rocks during the excavation of the road cut. B) Pull-apart forces acting in geologically recent times caused fault-block faulting, forming the mountain. C) Slide-past forces moved the rocks from Tennessee to Maryland, where the rocks piled up at a bend in a San-Andreas-type fault to form the Appalachians of Maryland. D) Push-together forces when Africa and Europe ran into the Americas bent the rocks, which later were exposed at the surface by erosion. E) Graffiti artists painted the roadcut to look like a bunch of bent rocks.

Answer: Push-together forces when Africa and Europe ran into the Americas bent the rocks, which later were exposed at the surface by erosion. A stop at Sideling Hill road cut is well worth the time. Walk out on the pedestrian overpass above Interstate 68 and admire the handiwork of a giant collision between the old world and the new.

What tectonic setting is primarily responsible for producing Crater Lake? A) Slide-past. B) Hot-spot. C) Push-together obduction. D) Push-together subduction. E) Pull-apart.

Answer: Push-together subduction. Crater Lake, the hole left by the cataclysmic eruption of Mt. Mazama, sits above a subduction zone, where one tectonic plate goes below another as they come together.

What tectonic setting is primarily responsible for producing Olympic National Park as well as the hills on which San Francisco is built? A) Hot-spot. B) Pull-apart. C) Push-together subduction. D) Slide-past. E) Push-together obduction.

Answer: Push-together subduction. The rocks of Olympic and San Francisco were scraped off the downgoing slab of the subduction zone.

What tectonic setting is primarily responsible for producing Olympic National Park as well as the hills on which San Francisco is built? A) Hot-spot. B) Push-together subduction. C) Pull-apart. D) Slide-past. E) Push-together obduction.

Answer: Push-together subduction. The rocks of Olympic and San Francisco were scraped off the downgoing slab of the subduction zone.

The main types of boundaries between different lithospheric plates are: A) Hot spots. B) Pull-apart and slide-past. C) Push-together and slide-past. D) Push-together, pull-apart and slide-past. E) Car-crash" boundaries, formed where Pepsi trucks hit Coke haulers.

Answer: Push-together, pull-apart and slide-past. There are three "end-member" behaviors that are possible with big plates that move around on the surface of the Earth. Intermediates exist, such as pushing together while sliding past. Hot spots poke through the plates, but don't make boundaries of the plates.

In a humid-temperate climate such as that of Pennsylvania or Washington, DC, weathering breaks down granite to produce: A) Real Pepsi, with sugar and everything. B) Quartz sand and rust, that stay to help make soil, while aluminum, potassium and other ions dissolve and wash away. C) Diet Pepsi. D) Quartz sand and clay, that stay to help make soil, while iron and other ions dissolve and wash away. E) Quartz sand, clay, and rust, that stay to help make soil, while some ions dissolve and wash away.

Answer: Quartz sand, clay, and rust, that stay to help make soil, while some ions dissolve and wash away. Weathering of granite in Pennsylvania or Washington DC or other places where abundant rain falls makes some things (clay, rust, and quartz sand) that stay behind to contribute to soil, and other things (soluble ions) that dissolve and wash away very quickly.

National Parks are: A) Regions containing key biological resources that have been set aside for the enjoyment of future generations. B) Regions containing key geological resources that have been set aside for the enjoyment of the present generation. C) Regions containing key roller coasters that have been set aside for the enjoyment of you and your immediate friends. D) Regions containing key biological, geological or cultural resources that have been set aside for the enjoyment of the present generation and future generations. E) Regions containing key cultural resources that have been set aside for the enjoyment of the present generation and future generations.

Answer: Regions containing key biological, geological or cultural resources that have been set aside for the enjoyment of the present generation and future generations. Old Faithful, the giant sequoias, and Mesa Verde's cliff dwellings are waiting for you, and your grandchildren.

Fossil fuels are usually formed from: A) Remains of formerly living things buried by sediments in regions with much oxygen. B) Decay of Diet Pepsi. C) Remains of formerly living things covered by lava flows erupted in regions with much oxygen. D) Remains of formerly living things buried by sediments in regions with little oxygen. E) Remains of formerly living things covered by thrust faults in regions with much oxygen.

Answer: Remains of formerly living things buried by sediments in regions with little oxygen. Where oxygen is present in sediments, bacteria use the oxygen to "burn" organic materials, so oxygen and fossil fuels don't go together. And, Diet Pepsi is rather resistant to decay, and would not make fossil fuel.

Fossil fuels are usually formed from: A) Remains of formerly living things buried by sediments in regions with much oxygen. B) Remains of formerly living things buried by sediments in regions with little oxygen. C) Remains of formerly living things covered by lava flows erupted in regions with much oxygen. D) Remains of formerly living things covered by thrust faults in regions with much oxygen. E) Decay of Diet Pepsi.

Hot spots: A) Bring caffeine up beneath the Capitol Building to stir up trouble in Congress. B) Are found only under continents. C) Move around rapidly under the plates while the plates sit still. D) Are found only under oceans. E) Rise from as deep in the mantle as the core-mantle boundary to the surface of the Earth, bringing up heat and feeding volcanoes.

Answer: Rise from as deep in the mantle as the core-mantle boundary to the surface of the Earth, bringing up heat and feeding volcanoes. Earthquakes make sound waves that go through the whole Earth, and go slower through hotter, less-dense rocks. By putting out listening devices called seismometers around the Earth, and listening to the waves from many earthquakes in many places, scientists can map the hotter regions, and find that towers of hot rock come up from way deep in the Earth in some places. But, some other hot spots don't seem to start as deep. The hot spots don't seem to move around much, but the lithospheric plates drift around over the hot spots. Hot spots come up beneath continents and oceans, and can poke through both. No one has ever found caffeine in a hot-spot plume, although it is possible that other things stir up trouble in Congress.

Geologically speaking, the water table: A) Rises in elevation during times of drought as trees suck it up, and sinks during rainstorms as trees quit pulling up water because they are well-watered. B) Changes elevation randomly. C) Rises during or soon after rainstorms as spaces fill up, and sinks during droughts as water drains away. D) Never changes its elevation, because it is pinned by the creeks. E) Sits next to the coffee table in the Capitol Building.

Answer: Rises during or soon after rainstorms as spaces fill up, and sinks during droughts as water drains away. As trees suck up water during droughts, air enters spaces where water once was, so the water table (which is the bottom of the region with some air in spaces) must sink in elevation. Creeks do change in elevation between rain and drought (floods happen...), and while there are random elements in the world, this is surely not one of them. (Whenever someone claims something is random, at least suspect that the person is really saying "I don't know what I'm talking about, and I'm too lazy to find out.") And while there might be bottled water in the Capitol, geologically speaking, that is not the right answer.

What happened in the picture above? A) Divers have built the mud piles to slow down the river water and protect endangered clams that live along the coast. B) Rivers have delivered sediment to the sea, forming flat-topped deposits called deltas. C) A certain financially ailing airline that flies to Cincinnati and then Atlanta built this from thrown-out beverage cups as an advertisement. D) Rivers have delivered sediment to the sea, forming deltas that built up as they built out so that they still slope slightly downhill toward the sea. E) Turbulence where the rivers enter the sea has caused suspended sediment in the seawater to flocculate and settle, forming the deposits seen on the right.

Answer: Rivers have delivered sediment to the sea, forming deltas that built up as they built out so that they still slope slightly downhill toward the sea. Two deltas have formed where streams carry sediment from the hillside into the fjord in South Greenland. The main source of sediment is the streams from the land, not suspended sediment already in the sea water. And the deposits cannot be purely flat-topped, or the rivers would not flow across to get to the sea water in the fjord. Mollusks do live along the coast but are not being protected by intrusive changes to the coastline, nor do enough people visit here to be worth advertising Delta Airlines.

The two pictures above, I and II, show fossils inrocks from the Grand Canyon. Each is "typical"; the rocks near sample Icontain fossils similar to those shown in sample I, and the rocks nearsample II contain fossils similar to those shown in sample II.It is likely that: A) Sample I is from high in the cliffs of the Grand Canyon, and sample II is from much lower, near the river. B) Sample I is from high in the cliffs of the Canyon, and sample II is also from high in the cliffs of the Canyon. C) Sample I is from the north shore of Lake Winna-Bango, and sample II is from the south shore, where there is plenty of moose moss to munch. D) Sample I is from near the river, and sample II is from high in the cliffs of the Grand Canyon. E) Sample I is from near the river, and sample II is also from near the river.

Answer: Sample I is from high in the cliffs of the Grand Canyon, and sample II is from much lower, near the river. Sample I is a wonderful shell hash, or coquina, from the Supai Rocks well up the side of the Canyon, and contains shells from a great diversity of different creatures. Sample II includes algal-mat deposits (stromatolites) from the Precambrian Chuar Group of the Grand Canyon Supergroup, deep in the Canyon near the river, from a time when biology was not a whole lot more diverse than algal mats. Lake Winna-Bango featured in the gripping Dr. Suess tale of Thidwick, the Big-Hearted Moose, but is not pictured here.

Acadia is beautiful even in the rain and fog, but the park still doesn't have many sandy beaches, and this is surely not a sandy beach, the rocks are granite, broken off the granite bedrock. Why aren't there sandy beaches? A) The sand blew away in big storms. B) Acadia gets huge winter storms, and sandy beaches are not found where huge storms occur. C) The sand was mined and shipped to New Jersey to fill the beaches at Atlantic City. D) Sand is produced or supplied slowly enough, and sand loss to deep water is fast enough, that sandy beaches do not form. E) No sand is produced by weathering at Acadia, nor is sand supplied by rivers or glaciers.

Answer: Sand is produced or supplied slowly enough, and sand loss to deep water is fast enough, that sandy beaches do not form. Granite does weather to make sand, so some sand must be produced, but this is not a sand deposit, so sand loss must be fast enough to prevent large accumulations. The Park Service would not allow sand mining, and New Jersey would just go offshore to deeper water to dig up sand. And huge storms hit Florida and the Gulf Coast, but they have sandy beaches.

Most Americans support science because: A) The scientific method allows scientists to learn the Truth. B) All scientists are sexy. C) All Americans are fascinated by science. D) All Americans are bored silly by science. E) Science has helped make our lives easier, safer, etc.

Answer: Science has helped make our lives easier, safer, etc. Without science and technology, the great majority of us would be dead, so we tend to be supporters of science. Although we know that science works, we're never sure that it is completely right. Students so often discover things that professors missed, or that professors got wrong, that scientists would be silly to claim Truth. Comparing the TV ratings of the latest hit to the ratings of the latest science program on public broadcasting shows that many Americans are not fascinated by science, but the science-show ratings are above zero, so some people are fascinated by science. And hope as we might, it is unfortunately clear that not every scientist is sexy (just most of them are...).

The picture above is of the coast at Acadia National Park. Look at the shape of the rocky island marked with the big "I" in the middle of the picture.The most likely interpretation is that this was caused primarily by: A) Sculpting of the rocks by waves, followed by uplift of the rocks above sea level as the land rebounded from the weight of the ice sheets. B) Sculpting of the rocks by wind, followed by flooding as sea level rose at the end of the ice age. C) Sculpting of the rocks by a glacier, which flowed from the right to the left. D) Sculpting of the rocks by a glacier, which flowed from the left to the right. E) Sculpting of the rocks by stone masons hired by the Rockefellers, followed by donation of the sculpture to the people of Maine.

Answer: Sculpting of the rocks by a glacier, which flowed from the left to the right. The side of the rock that a glacier reaches first is sandpapered and rounded blocks are removed. The ice thus flowed from left to right, streamlining and smoothing the island. Wind and waves do not make such distinctive forms, and while Rockefeller stonemasons might have done so, they probably would have carved a huge likeness of a fabled ancestor instead.

In the picture above, the big W is in ocean water, while the little w is in water in a bay cut off from the ocean by the bar indicated by the pink dashed arrow. A stream flows toward the bay along the blue arrow, and coastal bluffs are indicated by the dashed yellow arrow.What probably happened here? A) A sinkhole opened behind the beach, and the stream slumped into the hole, leaving the bar. B) Sediment has been delivered from deep water to the land, building the bar and piling up to form the low bluffs. C) Sediment supplied by the stream has piled up to build the bar that separates the stream from the ocean. D) The navy dammed the stream valley to keep enemy submarines from sneaking in and launching missile attacks on the secret underground base under the stream. E) Sediment has been eroded from the land by waves crashing against the bluffs, and the sediment has been transported along the shore by longshore drift to build the bar.

Answer: Sediment has been eroded from the land by waves crashing against the bluffs, and the sediment has been transported along the shore by longshore drift to build the bar. Longshore drift is important, and moves much sediment. The greater width of the beach across the mouth of the stream than nearby shows how far waves can go; adjacent to the stream, the waves must cross the beach during storms and batter the bluffs, making sediment that feeds the longshore drift. Submarines are not a big worry in such shallow, near-shore settings, and sinkholes tend to be round, not elongated as seen here.

What is accurate about the land surface today, that you can observe in places such as Pennsylvania? A) Sediment is being deposited everywhere, covering the land surface deeper and deeper. B) Sediment is not being deposited anywhere, so everywhere is eroding. C) Sediment is being deposited in most places, but a few places are eroding. D) Sediment is being deposited in a few places, but most places are eroding. E) Sediment is not being deposited anywhere, and it never has been.

Answer: Sediment is being deposited in a few places, but most places are eroding. Today in Pennsylvania (and across most of the land surface of the planet), sediments are accumulating in a few human-made lakes, a few natural wetlands or natural lakes, along some streams and in some caves, but almost everywhere else is eroding. This is the typical state of affairs, so you need to correlate events across large regions to get a good geologic record.

Often, building a groin or "dam" sticking out into the water from a coast in a region where longshore drift is moving sand from "upstream" to "downstream" only partially solves the problem for which the groin was designed, because: A) Sediment is deposited upstream of the groin but eroded downstream of the groin. B) No change occurs in sediment. C) Sediment is eroded upstream of the groin and deposited downstream of the groin. D) Sediment is deposited on both sides of the groin. E) Sediment is eroded on both sides of the groin.

Answer: Sediment is deposited upstream of the groin but eroded downstream of the groin.

Often, building a groin or "dam" sticking out into the water from a coast in a region where longshore drift is moving sand from "upstream" to "downstream" only partially solves the problem for which the groin was designed, because: A) Sediment is deposited upstream of the groin but eroded downstream of the groin. B) Sediment is eroded upstream of the groin and deposited downstream of the groin. C) Sediment is deposited on both sides of the groin. D) Sediment is eroded on both sides of the groin. E) No change occurs in sediment.

Answer: Sediment is deposited upstream of the groin but eroded downstream of the groin.

Humans often try to change coastal processes to benefit us. One of the many things we do is to build walls, or groins, or jetties, to interrupt waves and currents and sediment transport. This example is from the coast of Washington.What has happened here? A) Sediment transport is typically directly from the ocean to the land, piling up sediment on both sides of the jetty. B) Sediment transport is typically from the right, causing deposition to the right of the jetty but no change to the left C) Sediment transport is typically from the upper left, and the sediment falls into the lee of the jetty on the right and piles up, while the left side is unaffected D) Sediment transport is typically from the upper left, and the sediment falls into the lee of the jetty on the right and piles up, while erosion happens on the left E) Sediment transport is typically from the right, causing deposition to the right of the jetty but erosion to the left

Answer: Sediment transport is typically from the right, causing deposition to the right of the jetty but erosion to the left A jetty works like a dam, trapping sediment on the "upstream" side and letting clean water pass to the other side, where the clean water erodes. So, the transport is typically from the right. A large beach has been formed there, but erosion "downstream" is cutting around the end of the jetty.

Geologically speaking, the water table: A) Rises during droughts, and sinks during rainy times. B) Separates the water-filled region near the Earth's surface from the deeper region with some air in the spaces. C) Sits next to the coffee table in the Capitol Building. D) Separates the water-filled region below the Earth's surface from the region closer to the surface in which some air exists in the spaces. E) Never changes its elevation, because it is pinned by the creeks.

Answer: Separates the water-filled region below the Earth's surface from the region closer to the surface in which some air exists in the spaces. The water table is the surface below which all the spaces are full of water, but above which there is generally some air in the spaces. During droughts, water drains away from the ground to the creeks, so air enters spaces previously occupied by water, and the water table drops in elevation. Creeks do change in elevation between rain and drought (floods happen...). And while there might be bottled water in the Capitol, geologically speaking, that is not the right answer.

Which is not evidence that glaciers were much bigger about 20,000 years ago than they are now? A) Shells of creatures that lived in the ocean about 20,000 years ago indicate that the ocean water was especially isotopically light then. B) Some land that does not have glaciers today bears the unique marks of erosion and deposition by glaciers, and those marks are about 20,000 years old. C) Prominent embayments such as Chesapeake Bay, with the form and sediments of old river valleys, are now flooded. D) Land bearing the unique marks of glaciers is rising today, while regions just around that land are sinking as deep hot rock flows back after being displaced by the glaciers. C) 20,000-year-old deceased shallow-water corals occur in growth position far below the surface on the sides of oceanic islands.

Answer: Shells of creatures that lived in the ocean about 20,000 years ago indicate that the ocean water was especially isotopically light then. The land with the unique glacier marks was pushed down by the ice and now is bobbing back up, water returned to the oceans from the melting ice caused sea level to rise, flooding river valleys and killing shallow-water corals as they lost their sunlight, but taking isotopically light water out of the oceans to grow ice sheets caused the remaining waters, and the shells, to be isotopically heavy.

What tectonic setting is primarily responsible for producing the great San Francisco earthquake and the San Andreas Fault? A) Push-together Obduction B) Hot Spot C) Push-together Subduction D) Slide Past E) Pull-Apart

Answer: Slide Past Not much mountain-building is happening along the central coast of California; the rocks slide past horizontally. The sliver of California to the west of a line connecting San Francisco to Los Angeles is sliding to the northwest, and as the sliver slides, it sticks and slips, making earthquakes.

There are many large mammals on Earth today. This is because: A) Dinosaurs in hibernation were killed by acid rain, which didn't hurt things that could run away. B) The very large mammals that were alive on Earth with the dinosaurs have gotten smaller over time because the mammals don't have to be big to compete with the dinosaurs any more. C) Small mammals were not able to outcompete the dinosaurs for big-animal jobs, but after the dinosaurs were killed, some large mammals evolved from small mammals to fill the large-animal jobs. D) The warm blood of the many large mammals that lived before the meteorite impact allowed them to survive the cold from the meteorite impact that killed the dinosaurs. E) Small mammals wanted to become bigger, and after the dinosaurs were killed, the small mammals had their chance and so made themselves bigger.

Answer: Small mammals were not able to outcompete the dinosaurs for big-animal jobs, but after the dinosaurs were killed, some large mammals evolved from small mammals to fill the large-animal jobs. There are "big-animal" jobs—eating tall trees, eating smaller animals, etc. But the total number of big-animal jobs is limited. The dinosaurs filled the big-animal jobs before mammals really got going, and mammals were not able to displace the dinosaurs. Some small mammals survived the meteorite that killed the dinosaurs, and then evolved to give big mammals over millions of years and longer. There were almost no big mammals before the dinosaurs were killed off, volition has nothing to do with evolution, and running away doesn't avoid acid rain.

In the picture above, the pink and yellow arrows in front of Dr. Alley point to two rather different deposits from an eruption of the Hawaiian Volcano Kilauea. As described in the class materials, these materials are: A) Materials that were raised along faults, as we saw last week near Bryce, and materials that were shoved under the faulted materials as melted intrusions. B) Materials washed into place by giant waves when the side of the island fell off. C) Small pieces thrown through the air, and frozen "waterfalls" of lava that flowed quietly before freezing. D) Giant bus-sized bombs thrown through the air by the violent eruptions, and interleaved thick lava flows that followed the violent eruptions. E) Materials that were lowered along faults, as we saw last week near Bryce, and materials shoved under the faulted materials as melted intrusions.

Answer: Small pieces thrown through the air, and frozen "waterfalls" of lava that flowed quietly before freezing. Mt. St. Helens and similar volcanoes make giant explosive eruptions that throw bus-sized blocks, but Kilauea in Hawaii usually doesn't (although rarely, water flashing to steam may move some big things!). Dr. Alley showed you the gravel-sized pieces of glass at the end of the pink arrow, and the frozen "waterfall" of lava at the end of the yellow arrow.

Mass wasting delivers sediment to streams. We believe that in regions such as Pennsylvania or the hills around Washington, DC, most of the mass that is delivered to streams arrives by: A) Careless people taking leaks in sinkholes after drinking too much Pepsi B) Soil creep, slow motion of pieces from freeze-thaw action, throw by falling roots, downhill motion of rocks during digging of gopher holes, etc. C) Very fast debris avalanches and flows D) Grain flows that occur when the soil dries out during summer droughts E) Slumps, like someone slumping down in an easy chair

Answer: Soil creep, slow motion of pieces from freeze-thaw action, throw by falling roots, downhill motion of rocks during digging of gopher holes, etc. As rocks move to streams in many places, such as Pennsylvania or near Washington, DC, the slow and steady motions are more important than the few dramatic events. In very steep mountains, fast landslides may dominate, and slumps can be important, but although Pennsylvania does have both, they are not especially common. On the side of a sand dune, you often can see a dry grain flow. (If you've ever sat high on a beach and sifted dry sand through your fingers, you've made a grain flow.) But these are very rare in Pennsylvania or near DC, where the soil tends to stick together even in summer. And while there may be careless people who misbehave in sinkholes, this won't get too many rocks to streams.

Mass wasting delivers sediment to streams. We believe that in regions such as Pennsylvania or the hills around Washington, DC, most of the mass that is delivered to streams arrives by: A) Slumps, like someone slumping down in an easy chair B) Grain flows that occur when the soil dries out during summer droughts C) Soil creep, slow motion of pieces from freeze-thaw action, throw by falling roots, downhill motion of rocks during digging of gopher holes, etc. D) Very fast debris avalanches and flows E) Careless people taking leaks in sinkholes after drinking too much Pepsi

Before they can be published, scientific papers must be peer-reviewed. This means that: A) Some other scientific experts read the papers and provide quality control by eliminating many mistakes. B) Government bureaucrats read the papers, to be sure that the papers do not insult the political positions of the current officeholders. C) An editor reads the papers, to make sure that all the semicolons are in the correct places. D) Some other scientific experts read the papers and guarantee that they are True. E) Everyone in the world is given the opportunity to comment on the papers through a specially maintained blog.

Answer: Some other scientific experts read the papers and provide quality control by eliminating many mistakes. Reviewers work hard to identify errors of any sort, almost always identify many, and then the reviewers and editors insist that those errors be fixed before publication. Review is done voluntarily by scientists; this is part of the cost of being a member of this great human undertaking. Science doesn't claim Truth; although science strives to be as accurate as humanly possible, that is often well short of Truth.

What causes the great majority of earthquakes? A) Stick-slip behavior across faults B) Implosions C) Explosions D) Well-lubricated sliding across faults E) Landslides

Answer: Stick-slip behavior across faults There may be "implosion" earthquakes, but they are rare. Some breaks in the crust are well-lubricated and don't make earthquakes. If rocks on opposite sides of a break move in the same direction at the same speed, then there will be no relative motion between those rocks, and they won't make earthquakes. But when rocks try to move in opposite directions but are stuck, they bend like springs and then break, shaking things and knocking them down in an earthquake. And Diet Coke drinkers who have not yet had their caffeine are unlikely to be sufficiently agitated to kick the Pepsi machines hard enough to make the larger earthquakes that are observed.

Hardy souls who visit beaches in the winter are often surprised by how different summer and winter beaches really are. A typical change is (note: a breaking wave curls over and the top falls down, making spectacular movie footage if a surfer is in the way; a surging wave hangs together and the top doesn't fall over): A) Surging waves bring sand in during winter, and breaking waves take sand out during summer, so summer beaches are small and rocky while winter beaches are large and sandy. B) Surging waves bring sand in during winter, and breaking waves take sand out during summer, so summer beaches are large and sandy while winter beaches are small and rocky. C) Surging waves bring sand in during summer, and breaking waves take sand out during winter, so summer beaches are small and rocky while winter beaches are large and sandy. D) Surging waves bring sand in during summer, and breaking waves take sand out during winter, so summer beaches are large and sandy while winter beaches are small and rocky. E) Cape Cod beaches are taken over by nudists in winter.

Answer: Surging waves bring sand in during summer, and breaking waves take sand out during winter, so summer beaches are large and sandy while winter beaches are small and rocky. Winter beaches are eroded, as breaking waves bring their energy far inland through the air, and the outgoing rush of water removes sand; surging summer waves replace that sand. And if you have ever been in a Nor'easter on the Cape, even hardy nudists would be in danger of losing certain important peripherals.

Geologists get to play with chemistry, physics, biology... and history! And what a history you will meet as you work your way through the course. Starting at the beginning, the textbook provides the scientifically accepted start of the story... and promises that you'll get to explore some of the evidence for that scientific view, later in the semester. Meanwhile, which is more nearly correct of the scientifically accepted view? A) The Earth formed from the falling together of older materials, about 4.6 billion years ago. B) The Earth was assembled by gigantic space beavers, which gnawed down the primordial tree of life and piled its branches together to form the planet. C) The Earth formed in the Big Bang, about 6000 years ago. D) The Earth formed when the Big Bang caused older materials to fall together, about 14 billion years ago. E) The Earth is eternal, having been here forever and promising to be here forever.

Answer: The Earth formed from the falling together of older materials, about 4.6 billion years ago. The Big Bang is estimated as having occurred about 14 billion years ago. Stars that eventually formed in the wake of the Big Bang led to production of elements such as iron and silicon that are common in the Earth—we are formed from second-generation stardust, which "got it together" to make the planet about 4.6 billion years ago.

What is more accurate about the Earth? A) The Earth is formed of flat, horizontal layers, a little cap at the South Pole, then a layer above that, and a layer above that, all the way up to a little cap at the North Pole. B) The Earth is formed of flat, vertical layers; one runs from the North Pole to the South Pole, and then others are layered on to the sides of that. C) The Earth is formed of concentric layers (something like an onion--a central ball with a shell around it, and a shell around that...); when the planet melted, it separated into layers. D) The Earth is formed of concentric layers (something like an onion--a central ball with a shell around it, and a shell around that...), but with a giant hole on one side where the moon-making collision blasted pieces off. E) The Earth is homogeneous; when it melted, it got all mixed up.

Answer: The Earth is formed of concentric layers (something like an onion--a central ball with a shell around it, and a shell around that...); when the planet melted, it separated into layers. The planet is onion-like, with an inner core, then an outer core, a mantle (which has several sub-layers), and a crust. The moon-making collision did happen, but the planet got hot enough to separate again. The planet separated after melting largely or completely, with the densest stuff falling to the center and the lowest-density stuff floating to the top.

We humans are changing the composition of the atmosphere in many ways. Those changes will directly affect the planet's temperature, but the resulting change in temperature will affect other things on the planet that also affect the planet's temperature. Suppose that we could magically change the composition of the atmosphere enough to raise the temperature one degree if all other parts of the Earth system were held fixed, and after the warming, we allowed the other parts of the Earth system to react for a few years or decades. At the end of that time, what would be the total change in the Earth's temperature? A) The Earth would end up a few degrees warmer than before the human influence, because positive feedbacks would amplify the original change. B) The Earth would end up cooler than before the human influence, as feedback processes oppose the tiny warming caused by the change in atmospheric composition. C) The Earth would end up one degree warmer than before the human influence, because positive and negative feedback processes would offset each other. D) The Earth would end up warmer than before the human influence but by less than one degree, because feedback processes would oppose the initial warming. E) The Earth would end up a few tens of degrees warmer than before the human influence, because positive feedbacks would amplify the original changes a whole lot.

Answer: The Earth would end up a few degrees warmer than before the human influence, because positive feedbacks would amplify the original change. Negative feedbacks stabilize the climate over long times of hundreds of thousands or millions of years or more, but feedbacks over years to millennia are mostly positive, amplifying changes. If there is a change in the sun, or CO2, or something else sufficient by itself to raise the temperature by one degree, this will be amplified to a few degrees by feedbacks.

We humans are on track to increase the amount of CO2 in the atmosphere so that the concentration in the future more than double the atmospheric CO2 concentration that existed for the few millennia before the industrial revolution. If we could cause just a doubling and then hold the CO2 level constant at that doubled level for the next thousand years, we very likely would see: A) The Earth would cool a few degrees, and then the temperature would stabilize at that new, cooler level. B) The Earth would warm many tens of degrees, and then the temperature would stabilize at that new, warmer level. C) The Earth would cool and cool, eventually causing a new ice age. D) The Earth would warm a few degrees, and then the temperature would stabilize at that new, warmer level. E) The Earth's temperature would remain the same as it was before the start of the industrial

Answer: The Earth would warm a few degrees, and then the temperature would stabilize at that new, warmer level. Doubling CO2 is estimated to warm the Earth by between 1.5 and 4.5oC, or 2.7 to 8.1oF, with some chance of slightly larger change and very little chance of smaller change. The physical basis of warming from CO2 is quite well understood, and cooling or no response is very unlikely. You might compare the expected warming from CO2 to getting up to put another blanket on the bed in the night if you are cold. True, you might spill a glass of water into the bed, or your significant other might steal the other blankets while you're up, so getting the extra blanket might make you colder, but common sense says that getting the extra blanket warms you. Warming from CO2 is about as certain as warming from the extra blanket—maybe a huge number of volcanoes will explode in the near future and offset the effects of the CO2, but don't count on it.

The top picture from the coast of Greenland, and the bottom picture from Bear Meadows Natural Area in central Pennsylvania, are geologically related. How? A) The Greenland picture shows where a fast landslide went through, and Bear Meadows was formed when a fast landslide dammed a stream. B) The Greenland picture shows where a fast landslide went through, and Bear Meadows was formed when a fast landslide ran down a hill, leaving a hollow behind that filled with water to become Bear Meadows. C) The Greenland picture shows the tracks of glaciers, and a glacier hollowed out Bear Meadows. D) The Greenland picture shows a lava flow, and a lava flow dammed a creek to make Bear Meadows. E) The Greenland picture shows rocks that have been creeping downhill on permafrost, and Bear Meadows probably was formed when such a creeping mass dammed a stream during the ice age.

Answer: The Greenland picture shows rocks that have been creeping downhill on permafrost, and Bear Meadows probably was formed when such a creeping mass dammed a stream during the ice age. Indeed, the hillslope in Greenland bears the unmistakable signs of creep on permafrost, carrying streams of rocks and bits of tundra downhill. Geologists are fairly confident that the Appalachians looked like this just beyond the glaciers during the ice age, and that rocks carried downhill this way dammed a stream to form Bear Meadows in central Pennsylvania.

In the picture above, when Dr. Alley slices his finger through the sand, he is recreating on a smaller scale what type of geologic process? A) The action of earthworms burrowing in loose soil. B) The action of waves making a beach in Hawaii. C) The action of an earthquake tearing apart continents. D) The action of mass wasting, as soil and rock collapses off of newly steep canyon walls initially carved out by water. E) The action of Chuck Norris karate chopping someone.

Answer: The action of mass wasting, as soil and rock collapses off of newly steep canyon walls initially carved out by water. Despite any passing resemblance, Dr. Alley is not using martial-arts techniques to extract money from sand. Instead, he is showing how a river carves a canyon, which then widens as mass wasting occurs on the steep new walls.

Your boss has assigned you to get the low-down on the latest wonder-drug and to be darn sure to get it right. You would be wise to consult: A) The article in the Journal of the American Medical Society, a peer-reviewed scientific journal, reporting on the discovery and testing of the drug. B) The Wikipedia; everything they publish is up-to-date. C) The New York Times article quoting the discoverer of the drug on how wonderful it is. D) The web site in the email you received with the subject line "Grow your ***** naturally with new wonder drug". E) The web site of the manufacturer of the wonder drug; they know more about it than anyone else does.

Answer: The article in the Journal of the American Medical Society, a peer-reviewed scientific journal, reporting on the discovery and testing of the drug. No source of information is perfect, but the refereed articles in learned journals put immense effort into "getting it right". The web has some reliable information, but probably most of the information on the web is not especially reliable. The web is very inexpensive, and lots of people put junk on it. The Wikipedia gets a lot of things right, but it is a distilled synopsis of the real stuff. Most newspapers are around for the long haul, and try to make the news fairly accurate, although some newspapers do have agendas, and the editorial pages are not especially accurate. But, if the report is on the views of a public figure, the newspaper may accurately report what the public figure said, but what the public figure said may be less than completely accurate. And while you are welcome to believe that an unsolicited email promising to grow your ***** will do so... don't count on it.

Beaches change size with every storm, but if you average over a few decades, the size of a typical sandy beach is usually controlled by: A) The balance between gain of quartz sand from weathering of granite bluffs just behind the beach, and loss of sand blown away to make sand dunes. B) The balance between sand loss to deep water, and sand supply from rivers or from coastal erosion. C) The balance between sand dug up from below by crabs, and sand taken inland in the shorts of small beach-goers. D) The balance between sand loss to the wind, and sand supply from glaciers. E) The balance between removal of sand from the beach by smaller summertime waves, and gain of sand from deep water by bigger wintertime waves.

Answer: The balance between sand loss to deep water, and sand supply from rivers or from coastal erosion.

People sometimes take machines out into deep water to "mine" sand, and bring it back to beaches. Dumping a lot of new sand on a beach usually causes: A) The beach to lose the new sand, but only after centuries or millennia, far to long to care about. B) The beach to grow for decades, as the new sand traps even more sand. C) The beach to lose the new sand over the next year or years, as waves and currents move the sand back to deeper water. D) The beach to grow for centuries or millennia, as the new sand traps even more sand. E) The beach to sink under the weight of the new sand, causing tidal waves to wipe out the boardwalks.

Answer: The beach to lose the new sand over the next year or years, as waves and currents move the sand back to deeper water. Waves and currents move lots of sand. If we want to offset this, we need to move a lot of sand, too. Building beaches from mined sand can work, but the sand heads back to deep water quickly, so in most cases the activity must be repeated every year or every few years to keep the beaches large and sandy.

If you hike down into Bryce Canyon, and you look up the correct stream bed, you'll see this.The trees lying across the stream bed in the photo above (between the pink arrows) are a small dam. What has happened here? A) Marmots dug out the space below the dam. B) A landslide came down the river, and the dam was built at the front of the landslide. C) The glaciers that carved the canyon left the sediment above the dam. D) A large sediment wave was moving slowly down the river, and the dam was built at the front of the sediment wave to stop the sediment, which it did. E) The dam has trapped sediment upstream, and the clean water coming over the dam has picked up sediment downstream of the dam and lowered the stream bed there.

Answer: The dam has trapped sediment upstream, and the clean water coming over the dam has picked up sediment downstream of the dam and lowered the stream bed there. Fast-flowing floods have lost their debris when slowed by the dam, filling the space above the dam with rocks. This basic pattern—dams collect debris and release clean(er) water that can erode more, is seen over and over in geology. And, marmots don't dig that much at Bryce!

The map above shows the Birdfoot Delta of the Mississippi River, where it empties into the Gulf of Mexico. The river is shown in blue, as is the Gulf of Mexico. The river "wants" to leave this delta, and flow somewhere else, far to the west of the area covered by this map. Why? A) As the mud of the delta sinks, the river loses its river banks, so it flows elsewhere. B) Humans have been damming the river at the end, so the river must go elsewhere. C) The meandering of the river has tied it in a knot, so it has to take a different path. D) The delta has built up as well as out, and that makes some other path to the Gulf steeper and shorter than the one now being taken, and during a flood the river tends to take that shorter path and cut a new channel. E) Hurricane Katrina, in 2005, plugged many of the river channels, so the river must go elsewhere.

Answer: The delta has built up as well as out, and that makes some other path to the Gulf steeper and shorter than the one now being taken, and during a flood the river tends to take that shorter path and cut a new channel. The river very nearly broke through the Old River control structure in a big flood, to take the shortcut down the Atchafalaya. The long path out to the end of the delta is not very favorable for the river, which has switched naturally in the past and would switch if humans allowed it to.

Volcanoes occur above the downgoing slab of a subduction zone. Why? A) The downgoing slab weakens the mantle, allowing hot-spots to come up along the slab and feed the Hawaiian-type basaltic volcanoes that are characteristic of subduction zones. B) The downgoing slab takes water and other things along, which lower the melting point down there enough to make melt that feeds the volcanoes. C) The downgoing slab rubbing along the overlying rocks makes a lot of heat, thus making the overlying rocks the hottest rocks in the mantle, which melts them to feed the volcanoes. D) The downgoing slab causes earthquakes that weaken the mantle, allowing convection cells to come up along the slab and feed the mid-ocean-ridge-type basaltic volcanoes that are characteristic of subduction zones. E) The sediments scraped off the downgoing plate make a pile, such as the Olympic, and this pile channels the Earth's magnetic field along the slab to cause melting.

Answer: The downgoing slab takes water and other things along, which lower the melting point down there enough to make melt that feeds the volcanoes. Throw a little dry flour in a warm oven, and not much happens. Add some water, or better, some water and some carbon dioxide from yeast, and things happen in a hurry. The subduction zone takes water, and carbon dioxide in shells and other things, down to lower the melting point and feed volcanoes. Friction does warm the down-going slabs, but slabs start off way colder than the rocks into which they move, and remain colder for a while. Sliding your cold feet along the sheets when you get into bed on a winter night may warm your toes a little by friction, but if you happen to share the bed with a significant other, putting your tootsies on that persons bare belly will tell you that frictional heating takes a while! The scraped-off pile of sediment traps a tiny bit of heat, but not too much; the downgoing slab makes the nearby mantle colder than normal, not warmer. And nature tends to separate regions where something is flowing one way from regions where the flow is reversed; if the flows are too close together, one will drag the other along and change its direction. Hot spots occasionally ride along on spreading ridges, because both involve rising, but not on subduction zones.

The picture above illustrates what scientific principle? A) The equator is hotter because it rotates faster, and the wind heats the surface as it rotates by, just as Dr. Alley can turn his head rapidly and cause heat by friction B) The equator is hotter than the pole because the sun hits the equator directly but the sun hits the pole a glancing blow C) The equator is hotter than the poles because most volcanoes are located near the equator, forced there by the centrifugal force of Earth's rotation, and Dr. Alley exhales hot air from his equatorial nose D) Dr. Alley is undoubtedly the sexiest human being on Earth E) The equator is hotter than the pole because the equator is closer to the sun than the pole

Answer: The equator is hotter than the pole because the sun hits the equator directly but the sun hits the pole a glancing blow Geometry is the main control on equatorial heating. Although the equator is closer to the sun than the pole, the difference is tiny and matters little to the temperature difference between equator and pole. The rotation of the Earth causes winds to turn as they blow over the surface, but does not heat the air. There is no clustering of volcanoes at the equator, and the heat from volcanoes is tiny compared to the heat from the sun. And we are quite confident that several celebrities and politicians believe that they are the worlds sexiest human being, so Dr. Alleys standing cannot be undoubtedly claimed.

In the photo above, Sam Ascah is standing on sand and gravel in a pothole, where a stream swirls during the short but intense thunderstorms of Zion National Park. And next to that stream, the other picture shows the sandstone and the hang-on-so-you-don't-fall-over-the-cliff chain along the trail. A likely interpretation of these features is: A) The potholes and the grooves behind the chain were gnawed by giant marmots. B) The grooves behind the chain have been cut over decades by motion of the chain as hikers grabbed it, and the potholes were cut by water swirling rocks around during the rare floods over much longer times. C) The potholes and the grooves behind the chain were gnawed by giant beavers. D) The Park Service carefully cut little grooves behind the chain before they hung it, so that it would look cute and slide well, and they cut the potholes so that hikers would have something to look at. E) The stream swirled rocks around and cut the potholes, and even bounced up the cliff to cut the notches behind the chain.

Answer: The grooves behind the chain have been cut over decades by motion of the chain as hikers grabbed it, and the potholes were cut by water swirling rocks around during the rare floods over much longer times. The chain really has hung there for decades, and has been scraped against the cliff dozens of times per day each summer, slowly wearing into the easily broken sandstone. The stream does swirl rocks around and slowly wear down the potholes. The potholes were there beside the cliff when the trail was established, and havent changed too much over decades.

On the Richter scale of earthquake intensity: A) The ground is shaken 3 times more by a magnitude-3 quake than by a magnitude-1 quake. B) The ground is shaken twice as much by a magnitude-5 quake as by a magnitude-2.5 quake. C) A magnitude-8.5 quake is impossible; nothing that big can occur. D) The ground is shaken 10 times less by a magnitude-3 quake than by a magnitude-2 quake. E) The ground is shaken 10 times less by a magnitude-4 quake than by a magnitude-5 quake.

Answer: The ground is shaken 10 times less by a magnitude-4 quake than by a magnitude-5 quake. One problem in describing earthquakes is that the ground shaking in the smallest one you can feel is 1,000,000,000 times smaller than the ground shaking in the largest quakes. We usually dislike having a scale that requires us to talk about an event of, say, size 100,000,000; instead, if a magnitude-1 quake moves the ground 10 units (say, 10 nanometers at some specified distance from the quake), than we say that a magnitude-2 quake moves the ground 100 units, and a magnitude-3 quake moves the ground 1000 units, and so on. You'll notice that the magnitude is just the number of zeros after the 1; this is a logarithmic scale.

Scientists say that glaciers flow. What does this mean? A) The ice is almost warm enough to melt, and so the ice deforms slowly something like the rocks in the mantle or a chocolate bar in your pocket. B) The ice kicks back and watches the football game on TV. C) The ice spins slowly in circles, because of the Coriolis force from Earth's rotation. D) The ice is so brittle that it crumbles when shaken by the wind, and the pieces roll downhill. E) The ice moves slowly downhill, because it is so cold and dense that it sinks through the rocks beneath.

Answer: The ice is almost warm enough to melt, and so the ice deforms slowly something like the rocks in the mantle or a chocolate bar in your pocket. Materials warmed almost but not quite to their melting point can deform without breaking or melting. We saw this with the great convection cells in the mantle, back in unit 2, and we meet it again with ice. If you list the temperature of the ice in degrees F, it is a lot colder than the mantle, or iron heated by a blacksmith, or a chocolate bar in your pocket. But, the ice has been warmed from absolute zero almost to the melting temperature, just like the mantle and the iron and the chocolate, so the stress from gravity can cause the ice to deform or flow.

In the picture above, Dave Janesko holds two rocks next to each other. The black one (to the upper left in the picture) is from a lava flow, and is much younger than the red one (to the lower right in the picture), which is a lake sediment. In nature, these rocks are found the way Dave is showing, with the younger black one next to the older red one rather than being on top of the older red one. As described by Dave Janesko in the online video, what happened here? A) The lava flow set the red rocks on fire, giving them their red color. B) The lake sediments were deposited, eroded into a big cliff, and then the lava flow filled the valley next to the cliff. C) A collision between two continents bent the rocks, forcing the lava flow next to the lake sediments. D) There once was a mid-ocean ridge here, and the black lava squirted up through a crack in the red lake sediments and then hardened; Dave Janesko is demonstrating what one side of the crack looks like. E) The lake sediments were deposited, then the lava flowed on top, and then a pull-apart Death-Valley-type fault formed, breaking the rocks and dropping the lava flow to be next to the lake sediments.

Answer: The lake sediments were deposited, then the lava flowed on top, and then a pull-apart Death-Valley-type fault formed, breaking the rocks and dropping the lava flow to be next to the lake sediments. The spreading that opened Death Valley affected a lot of the west, all the way over to Bryce Canyon in Utah. The Sevier Fault, just west of Bryce, formed as pull-apart action broke the rocks, allowing younger rocks including the black lava flow to drop down next to older rocks including the red lake sediments. There really are cases where lava hardens in cracks, or where lava flows fill valleys, but a careful examination of the rocks here shows that the lake sediments have not been heated by nearby lava, so these lake sediments and the lava must have been placed together after the lava cooled. Folding does occur, but not here.

Which is accurate about the Earth? A) The lithosphere usually breaks rather than flows, and the asthenosphere usually flows rather than breaks. B) The lithosphere usually flows rather than breaks, and the asthenosphere usually flows rather than breaks. C) The lithosphere and the asthenosphere freeze in the winter to make Pepsi slushees. D) The lithosphere usually breaks rather than flows, and the asthenosphere usually breaks rather than flows. E) The lithosphere usually flows rather than breaks, and the asthenosphere usually breaks rather than flows.

Answer: The lithosphere usually breaks rather than flows, and the asthenosphere usually flows rather than breaks. Litho means stone, and the lithosphere is the hard breakable layer, above the softer asthenosphere.

The United Nations-sponsored Intergovernmental Panel on Climate Change shared the 2007 Nobel Peace Prize. The information that the Panel has supplied to policymakers includes: A) The observed rise in atmospheric CO2 levels has been caused primarily by a sudden increase in explosive volcanism, and is causing the climate to warm. B) The observed rise in atmospheric CO2 levels has been caused primarily by human fossil-fuel burning, and very likely is causing warming of the climate that is unlikely to become much larger. C) The observed rise in atmospheric CO2 levels has been caused primarily by human fossil-fuel burning, and very likely is causing warming of the climate that is likely to become much larger if we continue our current behavior. D) The observed rise in atmospheric CO2 levels has been caused primarily by a sudden increase in explosive volcanism, and is having no effect on the climate. E) The observed rise in atmospheric CO2 levels has been caused primarily by human fossil-fuel burning, and is having no effect on the climate.

Answer: The observed rise in atmospheric CO2 levels has been caused primarily by human fossil-fuel burning, and very likely is causing warming of the climate that is likely to become much larger if we continue our current behavior.

At Cade's Cove in the Great Smoky Mountain National Park, there is an unusual arrangement of rocks where older rocks are sitting on top of younger rocks, though neither layer has been overturned. This is because: A) The older layer was thrust over the younger layer by the forces of obduction. B) George the Marmot did it. C) The younger layer subducted under the older layer. D) The younger layer was injected as molten material under the older rock and then solidified.

Answer: The older layer was thrust over the younger layer by the forces of obduction. The Great Smokies are an example of obduction, as are the Ridge-and-Valley mountains of the folded Appalachians, which include Penn State's University Park campus. However, up here the rocks were "rumpled up" but down in Cade's Cove, one set of rocks was thrust over another resulting in older rocks riding over younger rocks.

Which is not accurate about the Grand Canyon, in Arizona: The youngest rock layer at the canyon slants downward to the north beneath still-younger rocks of Zion, Bryce, etc. The rock record of the canyon contains many unconformities. The walls of the Canyon include rocks deposited in many different environments. A great thickness of sedimentary rocks exists in Death-Valley-type faulted basins, which can be seen deep in the canyon in many places. Correct! The oldest rocks are on top, with younger ones beneath, as shown by all of the footprints being upside-down in the rocks of the canyon walls.

Answer: The oldest rocks are on top, with younger ones beneath, as shown by all of the footprints being upside-down in the rocks of the canyon walls.

Which is not accurate about the Grand Canyon, in Arizona: A) The youngest rock layer at the canyon slants downward to the north beneath still-younger rocks of Zion, Bryce, etc. B) The rock record of the canyon contains many unconformities. C) The walls of the Canyon include rocks deposited in many different environments. D) A great thickness of sedimentary rocks exists in Death-Valley-type faulted basins, which can be seen deep in the canyon in many places. E) The oldest rocks are on top, with younger ones beneath, as shown by all of the footprints being upside-down in the rocks of the canyon walls.

Answer: The oldest rocks are on top, with younger ones beneath, as shown by all of the footprints being upside-down in the rocks of the canyon walls. There are some folded rocks in the heart-of-a-mountain-range metamorphics at the bottom, but otherwise, everything is right-side up. All the other possible answers here are correct.

During the most recent ice age, the great ice sheets produced many geologic features. Which of the following was NOT produced by the great ice sheets during that most recent ice age? A) Layers of rocks from Canada spread into Pennsylvania from the north. B) Moraines on Cape Cod. C) The piles of mud along the river crossing the Mississippi Delta. D) Layers of rocks from Canada spread into Minnesota and Wisconsin from the north. E) Moraines on Long Island, NY.

Answer: The piles of mud along the river crossing the Mississippi Delta. This is just a fact of geography; the ice didn't quite make it to the Mississippi Delta.

What is indicated by the arrows? A) The yellow arrows point to the original beach, but this is Greenland, and most of the beach moved to the pink arrows by soil-creep processes. B) The yellow arrows point to bars in the river, and the pink arrows point to a beach. C) The pink arrows point to a barrier beach or outer beach piled up by waves, and the yellow arrows point to a "washover" where a storm broke through the outer beach and moved sediment inland. D) The yellow arrows point to a coral reef, and the pink arrows point to a former coral reef that has been killed by global warming. E) The yellow arrows point to the original beach, which was overwhelmed by a flood that carried the sand out to the pink arrows.

Answer: The pink arrows point to a barrier beach or outer beach piled up by waves, and the yellow arrows point to a "washover" where a storm broke through the outer beach and moved sediment inland. Barrier beaches are piled up by waves, but especially strong storms often break through the beaches. Some of the sand at such new inlets is moved toward the land, often forming new beach-like deposits such as those indicated by the yellow arrows. Some sand is also often moved offshore into deeper water.

Dr. Alley once helped a Grand Canyon ranger answer a tourist's question: "Why is the Canyon wider at the top than at the bottom?"The tourist had their own favorite theory. Based on the materials that have been presented to you've in this class, what geologically accepted answer would Dr. Alley and the ranger have given the tourist? A) The river used to be much wider before the desert formed, and so cut a wide canyon, but the river has narrowed as the drying occurred, and now cuts only a narrow canyon. B) The bulldozer that made the canyon was wearing out its blade as it dug down. C) The river used to be much wider because it was not steep, and water spreads out when running slowly (a little tap feeds a big bathtub...); then, as the Rockies were raised, the river steepened and narrowed, so it used to cut a wide canyon and now cuts a narrow one. D) The river cuts down, and that steepens the walls of the canyon, which fall, topple, slump, creep or flow into the river to be washed away, thus widening the canyon above the river. E) The canyon is really the same width at the top as at the bottom, but the well-known "optical illusion" of distant things appearing smaller causes it to look as if the canyon is narrowing downward.

Answer: The river cuts down, and that steepens the walls of the canyon, which fall, topple, slump, creep or flow into the river to be washed away, thus widening the canyon above the river. The tourist suggested that the river has gotten narrower over time. Dr. Alley asked the tourist whether he would ever consider going out on a particular narrow pillar of rock (already teetering dangerously and separated from the walls of the canyon by a huge crack) with a few hundred of his closest friends, and jumping up-and-down vigorously. Predictably, the tourist said "of course not, it might fall over." Dr. Alley then pointed out the many places where rocks clearly had fallen off the cliffs and moved downhill, at which point the tourist quickly switched his opinion to the "down-cutting" river explanation, with the ranger thoroughly enjoying the show.

Dr. Alley once helped a Grand Canyon ranger answer a tourist's question: "Why is the Canyon wider at the top than at the bottom?"The tourist had their own favorite theory; Based on what you've learned in class, what geologically accepted answer would Dr. Alley and the ranger have given the tourist? A) The river cuts down, and that steepens the walls of the canyon, which fall, topple, slump, creep or flow into the river to be washed away, thus widening the canyon above the river. B) The river used to meander, cutting a wide swath, but now runs straight, cutting a narrow swath. C) The river used to be much wider because it was not steep, and water spreads out when running slowly (a little tap feeds a big bathtub...); then, as the Rockies were raised, the river steepened and narrowed, so it used to cut a wide canyon and now cuts a narrow one. D) The canyon is really the same width at the top as at the bottom, but the well-known "optical illusion" of distant things appearing smaller causes it to look as if the canyon is narrowing downward. E) The river used to be much wider before the desert formed, and so cut a wide canyon, but the river has narrowed as the drying occurred, and now cuts only a narrow canyon.

Stephanie and Topher are standing next to the Colorado River in the Grand Canyon. What can be said of the water here? A) The river is really filled with 7-UP, hence the green color. B) The river was cleaned up briefly by the Park Service to help Stephanie and Topher in their filming. C) The river was naturally muddy, but has been made clear because most of the sediment is settling out in the reservoir behind the dam upstream. D) The river water is naturally clear, fed by snowmelt from the Colorado Rockies. E) The river water is kept clear by the Park Service to keep the trout healthy.

Answer: The river was naturally muddy, but has been made clear because most of the sediment is settling out in the reservoir behind the dam upstream. Native species that lived in the muddy waters are now in danger of becoming extinct, because the clear water released from the dam makes those fish too easy for predators to see.

The picture above shows a very hard piece of rock about six inches across, in the Grand Canyon.The surface of the rock looks rather different from the surfaces of many other rocks.What made this odd-looking surface? A) A glacier; the high plateaus adjacent to the canyon had ice-age glaciers that helped carve the canyon. B) The river, which blasted the rock with sand- and silt-laden water during floods; this shows that even hard rocks can be eroded by rivers. C) The wind, which has been primarily responsible for carrying away sand bars, and which sand-blasts rocks with the sand. D) The river; because the rocks are still there, this shows that rivers cannot really erode hard rocks and thus that the river could not have carved the canyon. E) A fault, which dropped old rocks so that they were preserved in Death-Valley-type valleys and so were not eroded away.

Answer: The river, which blasted the rock with sand- and silt-laden water during floods; this shows that even hard rocks can be eroded by rivers. The Canyon was carved by the Colorado River. Glaciers have not been there, and while wind and faults can change the appearance of rocks, none makes something like this river-polished rock, as you saw in one of the Grand Canyon V-Trips.

Shown above is Great Rock, Cape Cod National Seashore, with some of Dr. Alley's relatives for scale. The rock is metamorphic. The picture includes most but not all of the above-ground portion; the rock goes about as far below ground as above. What is the rock doing here in the middle of Cape Cod? A) The rock was used as ballast on the Mayflower, and left at First Encounter Beach as a present to the native Americans because the Mayflower no longer needed ballast in thenear-coastal waters. B) The rock rose up through the sand during a giant earthquake, the way large rocks are "floated" up in permafrost regions. C) The rock was carried here by glacier ice and left when the ice melted. D) Tsunami waves washed it here, when a huge landslide occurred from a volcanic island in the Atlantic Ocean. E) The rock was thrown here by the giant meteorite impact that hollowed out Hudson Bay.

Answer: The rock was carried here by glacier ice and left when the ice melted. Glaciers carry rocks of all sizes easily. Cape Cod is the product of glaciers, and almost everything natural on the Cape was delivered by glaciers originally. There rarely are big tsunamis in the Atlantic, but not this big. Nor is there any evidence of a big meteorite impact that is as young as Cape Cod. The east coast is rather free of large earthquakes, although Charleston, South Carolina gets a few occasionally. And the early settlers would not have put such a huge thing in the bottom of their ship (imagine having that bouncing around in a storm!), nor could they have taken such a rock out easily upon arrival.

In question 4, you estimated the time for lowering the surface of Happy Valley enough to account for the modern difference in elevation between the top of Mount Nittany and the bottom of the valley. In question 5, you saw that you could change that estimate a good bit. But, to make a 10-fold change in the estimate, you had to assume things that are really almost impossible, such as making central Pennsylvania one of the wettest places on Earth. We could tweak the assumptions in the calculation to move the estimate either way by a few-fold (so 10 million years could become 3 million years, or 30 million years, without too much trouble), but shifting the answer a whole lot further than that requires impossibilities or miracles--just because we can shift it to 3 million years or even 1 million years does not mean we can shift it to 10,000 years, which would require digging the valley 1,000 times faster than is happening now, which nature really cannot do here. We can say something else important, though. Whatever the time needed for deepening the valley, the geologic story of central Pennsylvania must be much longer than that-- time-deepening the valley is only the last act of a long play. The text of this exercise refers to several reasons why we know that the story is longer than the deepening of the valley. Which two statements below describe something indicating that the region is much older than calculated so far in this exercise? A) Mountains are always old. B) The rocks needed to be deposited, hardened, and bent before being eroded, and all of that took time. C) The geology of the region shows that the modern valley once had a mountain on top of it, so erosion had to take the mountain off before digging the valley, thus requiring a longer time. D) "Clams got legs", clams keep jogging to central Pennsylvania from the Chesapeake Bay and then dying, the stream has to carry the clams away, so that means that the time to dig the valley was more than 10 million years. E) The professor said this, so it must be true.

Answer: The rocks needed to be deposited, hardened, and bent before being eroded, and all of that took time. & The geology of the region shows that the modern valley once had a mountain on top of it, so erosion had to take the mountain off before digging the valley, thus requiring a longer time. As described in the exercise and as you are learning in class, the rocks we see were formed by processes that still occur, and that take time to happen. And, as you can see in the diagram in the introduction to this exercise, the modern site of the valley once was the site of the mountain, so more rock has been removed than you calculated, requiring more time. Some mountains are forming today and are not extremely old. If enough clams were reaching Happy Valley, they would affect the calculation, but you should have no worries about being stomped by jogging clams. We try very hard to make sure that the professors are giving you accurate information, but all of the information here is based on much more than the say-so of a professor!

Pieces of bedrock from Canada, north of Lake Superior, are spread across large areas of Wisconsin and Minnesota in the US, even though Lake Superior sits between the Canadian source of the rocks and the US places that the rocks now are. How do geologists explain this? A) The rocks were carried into Minnesota and Wisconsin by gophers and badgers. B) The rocks were "splashed" into the US from Canada by a meteorite impact that formed Hudson Bay. C) The rocks floated into the US from Canada in icebergs during a great flood. D) The rocks were carried into the US by ice but before Lake Superior was formed, because ice cannot flow uphill. E) The rocks were carried into the US from Canada by a glacier flowing from Canada; the base of the ice was able to flow uphill from Lake Superior into Minnesota and Wisconsin because the upper surface of the ice sloped down from Canada toward Minnesota and Wisconsin.

Answer: The rocks were carried into the US from Canada by a glacier flowing from Canada; the base of the ice was able to flow uphill from Lake Superior into Minnesota and Wisconsin because the upper surface of the ice sloped down from Canada toward Minnesota and Wisconsin. Ice, or pancake batter, or any pile, tends to spread from where its upper surface is high to where its upper surface is low. The Great Lakes are old features, but the base of the ice really did flow up out of the Great Lakes into the US because the top of the ice sloped down from Canada into the US.

Sea level can change locally for many reasons, but averaged over all of the oceans of the world: A) The seas are rising, because global cooling makes the glaciers grow and the ocean water expand. B) The seas are falling, because global warming makes the glaciers grow. C) The seas are rising, because global cooling makes the glaciers grow. D) The seas are falling, because global warming makes the glaciers grow and the ocean water expand. E) The seas are rising, because warming is causing the ocean water to expand and mountain glaciers to melt.

Answer: The seas are rising, because warming is causing the ocean water to expand and mountain glaciers to melt. Indeed, sea level is rising, by almost an inch per decade. The biggest reasons are melting of ice on land that releases water that flows into the ocean, and expansion of ocean water as it warms up.

Dust and shells and fish poop and all sorts of things fall to the sea bed to make sediment. Across broad central regions of the ocean, the sediment accumulates at a uniform rate—piling up about as rapidly here as it does over there. And, in most places, the currents don't move the sediment around much, so that it stays where it falls. Thus, the thickness of the sediment is related to the age of the rocks beneath the sediment. If you go around an ocean and measure the thickness of the sediment in lots of places, you are likely to find: A) The sediment is the same thickness everywhere. B) The sediment is thin near spreading ridges, and thicker away from the ridges. C) The sediment thickness forms waves, thicker thinner thicker thinner thicker thinner, as you cross the ocean, but with no influence from spreading ridges. D) The sediment is thick near spreading ridges, and thinner away from the ridges. E) The sediment thickness varies a lot from place to place, but the pattern is totally random.

Answer: The sediment is thin near spreading ridges, and thicker away from the ridges. Sea floor is made at the spreading ridges, and moves away on both sides. Sediment piles up over time, and while there are variations in sedimentation rate, the huge difference in age of the sea-floor rocks (140 million years near the edges of some ocean basins, to essentially zero at the ridges) is the main controlling factor on sediment thickness. Fish actually poop wherever they travel, and tend to go all over the oceans.

One practical radioactive system used to date lava flows involves: A) The solid potassium-40, which decays to the solid moosemossium-41. B) The gas argon-40, which decays to the gas potassium-40. C) The solid potassium-40, which decays to solid argon-40. D) The gas argon-40, which decays to solid potassium-40. E) The solid potassium-40, which decays to the gas argon-40.

Answer: The solid potassium-40, which decays to the gas argon-40. Potassium-40 is common in solid minerals, and decays to produce the gas argon-40. And despite his great contributions to humanity, no one has named an isotope after moose moss (the favorite food of Thidwick, for you Dr. Suess fans).

What probably happened in the above picture? A) Nothing B) Jeffrey pines such as this are known as multi-leader trees, and typically grow such a trunk for extra support. C) The tree started with its roots underground, but erosion washed the dirt away from them, so now they stick out. D) The Park Service hired an expert in topiary, the growth of interesting trees, to make sculptures such as this along the rim of Bryce Canyon. E) The tree initially sprouted on another stump, which was removed by the Park Service after new growth had occurred for a while, leaving the tree we see now perched on roots that encircled the original stump.

Answer: The tree started with its roots underground, but erosion washed the dirt away from them, so now they stick out. Erosion can be rapid in steep places with weak rocks, such as here on the rim of Bryce Canyon, uncovering formerly-underground tree roots. In wet places, you sometimes can observe a tree growing on an old stump, but this is a somewhat dry site with no evidence of stumps to be used for such a purpose, and the Park Service would not come in and root out a stump from under a tree. The park service promotes nature, not human sculpting of trees. This is not a Jeffrey pine, and pines in general do not grow multiple trunks. But a lot did happen here, and is still happening.

Most landslides happen when: A) The unconsolidated materials on hillslopes are very wet and thus heavy and slippery, and the water doesn't have to "break" as the grains move. B) The unconsolidated materials on hillslopes are paved with concrete. C) The unconsolidated materials on hillslopes are damp, so the grains are made slippery by the water. D) The unconsolidated materials on hillslopes are dry, so the grains roll easily downhill. E) The unconsolidated materials on hillslopes are paved with blacktop.

Answer: The unconsolidated materials on hillslopes are very wet and thus heavy and slippery, and the water doesn't have to "break" as the grains move. Dry sand can move, but even very dry times on hillsides usually don't cause landslides. But let a hurricane really saturate things, and all heck can break loose. Paving causes lots of changes, but landslides are not usually the result.

The floor of Death Valley is about two miles lower than the mountain peaks around it. How did this happen? A) The valley floor has dropped by more than two miles relative to the mountains, but erosion has removed the mountain tops and the sediment produced has partially filled the valley, leaving an elevation difference of two miles. B) The valley was once filled with a giant lake of coffee, and early miners collected the coffee and hoarded it so they could sell it to Congress under an exclusive licensing agreement. C) The elevation difference between the peaks and valley was once much larger than two miles, but the valley floor has been rising as it is inflated by lava from below. D) The valley was carved two miles deep by a prehistoric river, much in the same way that the Colorado River carved the Grand Canyon. E) The valley floor has dropped by exactly two miles relative to the mountains.

Answer: The valley floor has dropped by more than two miles relative to the mountains, but erosion has removed the mountain tops and the sediment produced has partially filled the valley, leaving an elevation difference of two miles. Watch a stream flowing into Death Valley (or any other valley) during a thunderstorm, and you will see that the water is full of rocks, mud, etc. The mountains are being eroded, and the loose pieces are carried down and dumped into the valley. Yet the mountain peaks are still two miles above the floor of Death Valley; the erosion and deposition are fighting against faulting that has dropped the valley by more than two miles relative to the mountains. No river carved the valley; the rivers are filling it up. And strange as it may seem, the valley is older than Congress or brewed coffee.

Statistically, and based on how many people are likely to die if they engage in or are exposed to the following problems, which is most dangerous to residents of the United States: A) Meteorite impacts. B) Tornadoes. C) The various diseases that come from smoking, overeating and under-exercising for a long time. D) Commercial airline crashes. E) Earthquakes.

Answer: The various diseases that come from smoking, overeating and under-exercising for a long time. There are still meteorites in the solar system that can hit and kill, and a reputable study found that a meteorite impact might not occur for millions of years (or might occur next year...) but then might kill billions. Add up the deaths over a sufficiently long time, and plane crashes (which kill a few to a few hundred people per year) and meteorite impacts likely would be similarly dangerous. Earthquakes and tornadoes, as devastating as they can be, don't kill as many people in this country as do airline crashes. Smoking, overeating and underexercising are way more dangerous to us.

Suppose that all the rainfall that fell during an average year on a typical surface in central Pennsylvania just stayed there as a layer of water (and all the snow melted, and the melt just stayed there). If at the end of the year you were standing on that surface (assuming you are a typical-sized human being), what would be true? (Pennsylvania gets about the same amount of precipitation as the average for the world.) A) The bottom of your toes would be wet, but not much else. B) The water would be over your ankles, but no deeper. C) The water would just cover your toes, but no deeper. D) You would need your SCUBA gear, or a really long snorkel, to keep from drowning because the water would be way over your head. E) The water would be up around your waist or chest, but you'd still be able to breathe.

Answer: The water would be up around your waist or chest, but you'd still be able to breathe. A typical rainfall supplies about an inch of water, or just under 0.1 foot. 30 feet of rain would be a big storm every day, about equal to the wettest place on Earth, and while sometimes it may seem the rain in Pennsylvania will never end, there really are clear days. 0.3 feet is a mere 3 or 4 rainfalls per year, and is a dry desert. 0.03 feet would be the driest place on Earth, and 0.003 doesn't occur on Earth. 3 feet is a nice number, which would be up to your chest, but you'd be able to breathe.

Above is a "beach" at Acadia National Park. The pieces are granite. A) There is no sand here, because Acadia and the surrounding coast of Maine get huge storms, and sandy beaches cannot exist where such huge storms occur. B) There is no sand here, so this must be a place where sand is not produced. C) There is no sand here, so sand must be lost to deep water fast enough in comparison to sand supply that sandy beaches have not formed. D) There is no sand here, because the Park Service mines the sand to pave park roads. E) There is sand under the rocks; the Park Service places the rocks on top to protect the beach, and takes the rocks off on sunny days.

Answer: There is no sand here, so sand must be lost to deep water fast enough in comparison to sand supply that sandy beaches have not formed. Granite does weather to make sand, so some sand must be produced, but this is not a sand deposit, so sand loss must be fast enough to prevent large accumulations. The Park Service neither mines sand from beaches, nor hides sand on beaches. And huge storms hit Florida and the Gulf Coast, but they have sandy beaches.

The photograph above shows some rocks in Great Smoky Mountains National Park. From looking at the rocks, and what you know about the park, a likely story is that: A) These rocks were buried deeply and squeezed in a continent-continent collision, and then brought to the surface in one of the giant volcanic eruptions that built the Smokies. B) These rocks were stretched and then snapped back, bending as they did so and making an earthquake. C) These rocks were sheared in the great slide-past fault that slid rocks from Florida up to the North-Carolina/Tennessee border to form the Smokies. D) These rocks were buried deeply and squeezed in a continent-continent collision, and then brought to the surface as overlying rocks were eroded. E) These rocks are really marmot #2.

Answer: These rocks were buried deeply and squeezed in a continent-continent collision, and then brought to the surface as overlying rocks were eroded. The squeezing and heating of an obduction zone have changed these rocks from mud to the folded schist seen here, and then erosion has revealed the rocks at the surface. There were large volcanoes near where the Smokies are before the Smokies formed, but those volcanoes ended when subduction ceased and obduction started to build the Smokies. Some slide-past motion did occur in the Appalachians, but not a huge amount, and the Smokies were not brought up from Florida.

What do the ptarmigan and the marmot below have in common? A) They are both standing on glacially deposited surfaces. B) They are both standing on periglacially cryoturbated surfaces. C) They are both flatulent mammals. D) They are both silicon-based life forms. E) They are both standing on glacially eroded surfaces.

Answer: They are both standing on glacially eroded surfaces. The carbon-based bird, top, would be unhappy if you accused him of being a silicon-based flatulent mammal. Periglacial cryoturbation produces sorted stone circles, and glacial deposition makes till or outwash. The striated, polished granites under these cold-climate critters were eroded by glaciers.

If you drive for 2 hours, at 60 miles per hour, you will have traveled 120 miles. This is a very common type of calculation, involving three quantities: distance, rate and time. If you know just two of these three quantities, you can always calculate the third. Thus, if you want to know how much time it is going to take you to get somewhere, and you know that the distance is 120 miles and you will drive at a rate of 60 miles per hour, you can divide the 120 miles by the 60 miles per hour and obtain a time of 2 hours. For this exercise, you will be relating distance, rate and time. The distance we will work with is the depth of Happy Valley. (Remember that even more rock has been removed than the depth of the valley, because the site of the modern valley once was higher than the site of the modern mountain, and the site of the modern mountain has been lowered somewhat as well. And, the rocks had to be deposited, raised and bent before the erosion could occur. So, you're calculating how much time was involved in a small part of the much longer history of central Pennsylvania.) We can measure how rapidly rock is being dissolved and washed out of Happy Valley, and use some fairly simple physical ideas to turn that into the rate at which the valley floor is being lowered. That gives you a distance (the valley depth) and a rate ( the speed at which the valley floor is being lowered), allowing you to calculate the time that has been used in the lowering. To get the correct answer, you will calculate the time from which equation: A) Time=Distance squared multiplied by Rate squared B) Time=Distance divided by Rate C) Time=Distance minus Rate D) Time=Distance plus Rate E) Time=Distance multiplied by Rate

Answer: Time=Distance divided by Rate You need to calculate time, so that should be on the left. How far (distance) divided by how fast (rate) will give you time. If you remember doing this with units, time (in hours) is calculated by dividing distance (in miles) by rate (in miles per hour), because: hours=miles/(miles/hour).

A dam is built on a river, forming a reservoir. Over time, this likely will cause the fields of some farmers along the river just upstream of the reservoir: A) To dry out as the water table falls. B) To become saturated with Pepsi. C) To experience no changes. D) To be buried by sediment. E) To be washed away as the river cuts downward while the extra sediment is deposited below the dam.

Answer: To be buried by sediment. The stream will slow where it enters the new lake, and so will deposit sediment to form a delta rather than cutting downward or having no change. As the delta builds out into the lake, the upstream end of the delta must build up so that the stream still slopes downward, and this will tend to bury fields upstream. The water table will rise as the lake floods formerly dry regions, but the lake is highly unlikely to contain Pepsi, which has a carefully guarded formula.

Your friend wants to see some real Pennsylvania coals. Where should you send your friend to see coal in the rocks of Pennsylvania (if you honestly are being helpful), and what coals would your friend see? A) To the metamorphic rocks of eastern Pennsylvania to see lignite, and to the sedimentary rocks of western Pennsylvania to see more lignite. B) To the metamorphic rocks of eastern Pennsylvania to see bituminous, and to the sedimentary rocks of western Pennsylvania to see anthracite. C) To the sedimentary rocks of western Pennsylvania to see bituminous, and to the metamorphic rocks of eastern Pennsylvania to see anthracite. D) To the metamorphic rocks of eastern Pennsylvania to see bituminous, and to the sedimentary rocks of western Pennsylvania to see more bituminous. E) To Ohio; there is no coal in Pennsylvania, but some Ohio coal is shipped through Pennsylvania.

Answer: To the sedimentary rocks of western Pennsylvania to see bituminous, and to the metamorphic rocks of eastern Pennsylvania to see anthracite. Bituminous is found with sedimentary rocks, but ones that have been squeezed and heated a bit so they are held together well and are not much like loose sediment; such rocks are common in western Pennsylvania. Anthracite is the most-cooked coal, and is found with metamorphic rocks in eastern Pennsylvania. Pennsylvania has lots of coal, but not much lignite, which would not be found in metamorphic rocks anyway.

The "Law" of Faunal Succession: A) Was passed in Congress to dictate equal teaching of different theories of origins. B) Was developed by theoretical biologists to explain evolution. C) Requires that evolution was a catastrophic process. D) Was developed by an engineering geologist to aid in construction projects. E) Requires that evolution occurred.

Answer: Was developed by an engineering geologist to aid in construction projects. In the late 1600s in England, William Smith discovered that putting the rocks in time order put the fossils in time order, allowing him to use the fossils as a shortcut in understanding the rocks. We will see soon that faunal succession is consistent with evolution but does not require it, does not require but might allow catastrophism, and informed but was not developed by theoretical biologists. Faunal succession was known before Congress was founded.

The picture above shows a region of hard rock about six inchesacross from the Grand Canyon. The shape and polish of the rock areinteresting. It is likely that the rock: A) Was scratched and polished by the hooves of mules carrying tourists into the Canyon along the Bright Angel Trail. B) Was scratched and polished by motion along a fault, which helped open the Canyon so that weathering could lower the Canyon floor. C) Was scratched and polished by a glacier, which helped erode the Canyon during the ice age. D) Was scratched and polished by the wind, which howls through the Canyon carrying loads of sand eroded from sand bars. E) Was scratched and polished by silt-laden river water, during carving of the Canyon by the Colorado River.

Answer: Was scratched and polished by silt-laden river water, during carving of the Canyon by the Colorado River. The Canyon was carved by the Colorado River. Glaciers have not been there, and while wind, faults and mule hooves all can change the appearance of rocks, none makes something like this river-polished rock, as you saw in the class materials including in one of the Grand Canyon slide shows.

The law that established Yellowstone as the first national park: A) Was written by socialists, because it mentions the word "society". B) Clearly was written by political conservatives, because it required conservation of the parks even if that means locking people out today. C) Clearly was written by politicians running for reelection, because it required that the parks make people happy today even if things are damaged for the future. D) Was written by communists, because park rangers have installed commodes in commodious outhouses. E) Was written to help people today and in the future, by requiring that the parks provide enjoyment today while preserving the parks for the future.

Answer: Was written to help people today and in the future, by requiring that the parks provide enjoyment today while preserving the parks for the future. The law that established Yellowstone as the first national park required "conservation... unimpaired for...future generations" and "to provide for the enjoyment" of the parks. But what if so many people want to visit that they scare the wolves, or trample the soil and kill the roots of the big trees? Enjoying and preserving at the same time isn't easy!

In the picture above, Dr. Alley is discussing events that are happening outside of Grand Canyon National Park, which may impact the park.What are the issues he is discussing? A) Plastic pieces, such as the straw he is holding in the picture to your right, are littered outside the park, and will break down and release toxins that pollute the waters of the park. B) Water spread on golf courses is introducing nitrates into the park. C) Water spread on golf courses is causing flooding in the park. D) A terrible shortage of Pepsi has alarmed the Park Service. E) Water pumped out of the ground for golf courses and other uses evaporates, so less water flows through the ground to the springs of the canyon.

Answer: Water pumped out of the ground for golf courses and other uses evaporates, so less water flows through the ground to the springs of the canyon. Water soaks into the ground on the plateaus beside the canyon, seeps down to hit a rock layer that blocks the flow, and flows along that layer to feed beautiful and biologically important springs in the Canyon. Pumping water out of the ground on the plateaus to use for humans generally allows the water to evaporate (say, from the grass of a golf course) or run down a stream (say, below a sewage treatment plant), so the water doesn't flow through the ground to the springs.

In the picture above, Dr. Alley is discussing events that are happening outside of Grand Canyon National Park, which may impact the park.What are the issues he is discussing? A) Water spread on golf courses is introducing nitrates into the park. B) Plastic pieces, such as the straw he is holding in the picture to your right, are littered outside the park, and will break down and release toxins that pollute the waters of the park. C) Water pumped out of the ground for golf courses and other uses evaporates, so less water flows through the ground to the springs of the canyon. D) A terrible shortage of Pepsi has alarmed the Park Service. E) Water spread on golf courses is causing flooding in the park.

Large rivers sometimes have natural levees because: A) Point bars run together to make levees. B) The mud deposited by the river compacts and sinks. C) Oxbow lakes run together to make levees. D) Water slows and deposits sediment as the water leaves the main river channel during floods. E) There are no natural levees.

Answer: Water slows and deposits sediment as the water leaves the main river channel during floods. The initial slowdown as water spreads into the trees deposits sediment to form natural levees. Sinking mud doesn't make ridges. Point bars are the sand bars on the insides of meander curves, and oxbow lakes are abandoned meander curves, but neither makes the natural levees that are observed.

The picture above shows ocean in the upper right, a beach, and land in the lower left. The red dashes trace the crest of a wave. Waves move perpendicular to their crests. What principle might be illustrated by the picture? A) Coasts always have sandy beaches. B) Waves come in faster than they go out, so beaches are eroded in summer when breakers are common. C) The picture is red, white and blue, demonstrating that Pepsi has outbid Coke for the professor's subliminal-advertising opportunities. D) Waves always curve because of the rotation of the Earth. E) Waves go slower in shallower water.

Answer: Waves go slower in shallower water. The rotation of the Earth has only miniscule effect at scales this small. Waves do go slower in shallower water, so as one end nears the coast, that end "waits" for the other end to catch up, causing waves to be going almost straight toward the shore when they run up the beach. There certainly are non-sand-beach coasts, and Pepsi has shown no interest in buying off the professor.

The picture above shows ocean in the upper right, a beach, and land in the lower left. The red dashes trace the crest of a wave. Waves move perpendicular to their crests. What principle might be illustrated by the picture? A) The picture is red, white and blue, demonstrating that Pepsi has outbid Coke for the professor's subliminal-advertising opportunities. B) Waves always curve because of the rotation of the Earth. C) Coasts always have sandy beaches. D) Waves go slower in shallower water. E) Waves come in faster than they go out, so beaches are eroded in summer when breakers are common.

The mountain range that contains the folded Appalachians, including Mt. Nittany near Penn State's University Park Campus, and the Great Smoky Mountains, was raised to high elevation primarily: A) When a subduction zone formed under Oregon, rumpling the rocks to the east. B) When a hot spot erupted under the east coast, and the surrounding rocks slid down the hill it made and rumpled while sliding. C) When the proto-Atlantic ocean closed, at a push-together boundary. D) When Death Valley opened, squeezing the east coast. E) When the Atlantic Ocean formed, at a pull-apart boundary.

Answer: When the proto-Atlantic ocean closed, at a push-together boundary. Run a car into a brick wall and the front of the car is crunched and bent. Fly over the folded Appalachians and you'll see the same pattern. There was a little Death-Valley-type uplift next to regions of down-dropping to the east of the Appalachians when the pull-apart happened, but the style of the Appalachians doesn't look like Death Valley, and the mountains were already here when the pulling apart started. We can see that the rumpling from the subduction zone in Oregon extends only 100 miles or so in from the coast, and even the Rockies required a special explanation as to why they are so far inland; the Appalachians are too far away to have been affected by subduction under Oregon. We can see that the Appalachians don't make a circle around a hot spot; they make a long belt parallel to the east coast. The Appalachians are way older than Death Valley, and with the Great Plains in-between, it is clear that the influence of Death Valley does not extend to rumpling rocks near the east coast.

In the picture above, the yellow line lies along the contact between sandstone (on the left) and reddish mudstone (on the right). The red arrows point along a place where the sandstone continues into the mudstone. The four sides of the picture are labeled A, B, C and D. What is most likely correct about these rocks? A) The rocks were formed from lava flows far down in the Earth, and were not deposited. B) When the rocks were deposited, side B was the lowest (it was on the bottom). C) When the rocks were deposited, side D was the lowest (it was on the bottom). D) When the rocks were deposited, side C was the lowest (it was on the bottom). E) When the rocks were deposited, side A was the lowest (it was on the bottom).

Answer: When the rocks were deposited, side D was the lowest (it was on the bottom). This is a cliff in the Grand Canyon. The picture was taken and then turned on its side. Originally, the muds of side D were deposited on a floodplain, a mud crack formed and sand fell into it (the red arrows) as the sand-dune rocks of side B were deposited on top.

Which of the following was probably important in contributing to extinction of most species at the same time the dinosaurs became extinct? A) Changed weather patterns because the meteorite caused large true polar wander (the north pole shifted rapidly in comparison to the continents because the meteorite rolled the planet on its side). B) Cold from the change in Earth's orbit caused when the meteorite shoved the planet farther from the sun. C) Intense rays emitted from radioactive materials in the meteorite. D) Heat from the change in Earth's orbit caused when the meteorite shoved the planet closer to the sun. E) Wildfires caused by great heat from rocks warmed by atmospheric friction while falling back to Earth after being blasted high in the atmosphere by the impact.

Answer: Wildfires caused by great heat from rocks warmed by atmospheric friction while falling back to Earth after being blasted high in the atmosphere by the impact. The meteorite impact was not nearly large enough to move the planet notably or to roll the planet over. There is a bit of extra radioactivity in meteorites (caused by cosmic rays, which reach a meteorite more easily than they reach the Earth because the Earth is shielded by its atmosphere), but only in comic books is there enough radiation from the extra radioactivity to really make a difference. The wildfire hypothesis is credible, and the large load of soot in the odd layer marking the extinction of the dinosaurs argues in favor of the wildfires having occurred.

Can a good geologist ever find a material that is somewhere between sedimentary rock and metamorphic rock? A) No, because nature lacks intermediates between the things we have named. B) Yes, because sedimentary rock is changed to metamorphic rock by people with Diet Pepsi bottles, and intermediates exist. C) No, because sedimentary rock and metamorphic rock were formed when the Earth formed, and intermediates cannot be formed. D) Yes, because sedimentary rock is changed to metamorphic rock by people with heat guns, and intermediates exist. E) Yes, because squeezing and heating sedimentary rock makes metamorphic rock, and intermediates exist.

Answer: Yes, because squeezing and heating sedimentary rock makes metamorphic rock, and intermediates exist. More heat and squeezing turn sedimentary rock to metamorphic rock. Where we change the name says a lot about us, and less about nature.

You develop a new idea, which is in conflict with a widely accepted scientific idea. For your new idea to gain widespread acceptance, you probably will need to show that: A) Your new idea is informed by Diet Pepsi ads. B) The development of the old idea was influenced by the socially conditioned ideas of the scientists involved. C) Your new idea does a better job than the previously accepted idea in predicting the outcome of one experiment that you conducted. D) Your new idea does a better job than the previously accepted idea in predicting the outcomes of an interlocking web of important experiments or observations. E) Your new idea is consistent with your interpretation of received wisdom from sacred books.

Answer: Your new idea does a better job than the previously accepted idea in predicting the outcomes of an interlocking web of important experiments or observations. At last observation, Pepsi commercials were not highly scientific, even if science is involved in figuring out what sells. It is a romantic notion that you could overturn great knowledge with a single observation; however, observing nature is not easy, and nature occasionally fools us (you can, rarely, flip an honest coin twenty times and get twenty heads), so if a single observation disagrees with a lot of other information, that single observation will be checked in various ways to see if the new result "stands up" before the older body of knowledge is discarded. Before an idea gains wide currency, that idea is tried in various ways, in many labs, in many places in nature, while models are run and theory is developed. The interlocking of all of these provides the confidence that scientists can use in doing things successfully. Although received wisdom from sacred books can be used for inspiration, scientific ideas must be tested against nature. Social scientists have quite rightly learned that scientists are affected by their prejudices, their funding sources, their mating habits, and other things, and that the path of science is not nearly the straight-ahead road to understanding presented in some textbooks. Unfortunately, some of those social scientists have then gone off the deep end and claimed that science is no more useful than any other human story—claiming that astrology and astronomy are equally valid, for example, or palm-reading and modern medicine. These same social scientists seem to know where to find a real doctor when they get in trouble, however. Science is appealed to nature, and builds on the learning of people from around the world. Airplanes that fly, computers that calculate, small devices that make big explosions, etc. are not socially conditioned ideas but instead are demonstrations of the success of science coupled to engineering.

The cartoon above illustrates a specific geologic process. Which of the additional geologic images DOES NOT feature this same process at work? (push together (dogs in cars crashing together))

Answer: pic of mountain surrounded by lake (crater lake or death valley is another possible answer) The folded Appalachians, including the region of central Pennsylvania around Penn State's University Park campus, shown in the satellite image here, as well as the Great Smokies and the Blue Ridge, formed when Africa and Europe collided with the Americas, much as the two cars in the picture collided. Crater Lake records different processes.

The next four (4) questions refer to the diagram above. This diagram shows a geologic cross-section of some rocks, such as you might see in a cliff. The tree is growing on top of the modern surface. Rock layers A, B, C, D, E, and F are sedimentary; E contains mud cracks and fossil footprints as shown. G is igneous rock that hardened from hot, melted rock. H, I and J are faults, and K and L are unconformities. Sedimentary rocks are right-side-up unless there is some indication given to show something else. Remember that footprints and mudcracks tell you whether rocks are right-side up or upside-down, so look for those. Also, if a layer is upside-down, so are the layers that are in the same sedimentary pile, until you hit an unconformity. So, if you have layers Q, R, S and T in one sedimentary pile beneath an unconformity, and then layer U above the unconformity, and you learn that Q is upside-down, so are R, S, and T, but you must look for more information to tell which way is up for U. Referring to the rocks you see here ......

Look at the 4 questions below

Answer:

The picture above shows: A) A right-side-up dinosaur track. B) Mud cracks. C) A sideways dinosaur track; the picture should be rotated ninety degrees clockwise to be right-side-up. D) An upside-down dinosaur track. E) A sideways dinosaur track; the picture should be rotated ninety degrees counterclockwise to be right-side-up.

Answer: An upside-down dinosaur track. This is a dinosaur track, from Dinosaur Ridge, and the dinosaur stomped down into the mud, so the track is upside-down; the instructional team used the power of modern computers to invert the picture.

Tsunamis: A) Are most commonly caused by whale flatulence. B) Are caused by changes in the rate of Earth's rotation. C) Are caused by earthquakes only. D) Are caused by earthquakes, undersea volcanic eruptions, or anything else that displaces a lot of water in a hurry. E) Are caused by especially large tides, earning them the nickname "tidal wave".

Answer: Are caused by earthquakes, undersea volcanic eruptions, or anything else that displaces a lot of water in a hurry. Throw a rock in the water, kick your foot in the water, swim in the pool, or even emit flatulence in the water, and you'll see one thing all have in common: they make waves. Earthquakes, volcanic eruptions, landslides, or meteorite impacts in the ocean can make waves big enough that we call them "tsunamis".

Regions with mountain glaciers that experience much surface melting in the summer typically are eroded: A) At a faster rate than regions with streams but no glaciers. B) At the same rate that natural rainfall dissolves granite. C) At the same rate as regions with streams but no glaciers. D) Not at all; no erosion occurs in typical regions with melting glaciers. E) At a slower rate than regions with streams but no glaciers.

Answer: At a faster rate than regions with streams but no glaciers. Yosemite Valley, Glacier National Park and other glaciated regions still bear the unmistakable marks of glaciers despite more than 10,000 years of modification by streams. Glaciers experiencing melting change the landscape faster than streams do.

Regions with mountain glaciers that experience much surface melting in the summer typically are eroded: A) At a slower rate than regions with streams but no glaciers. B) At the same rate as regions with streams but no glaciers. C) At the same rate that natural rainfall dissolves granite. D) At a faster rate than regions with streams but no glaciers. E) Not at all; no erosion occurs in typical regions with melting glaciers.

Which is the oldest sedimentary rock layer: F B C E D

Answer: C The package of sediments C, D, E, and F is upside-down, as shown by the footprints and mud cracks, so C is the oldest one.

Sediment is changed to sedimentary rock by: A) Cementation by hard-water deposits, intergrowth of new minerals, and squeezing under the weight of additional sediment. B) Chemical weathering of mineral surfaces. C) Cementation by oil. D) Compaction under the weight of additional sediments only. E) Cementation by hard-water deposits only.

Answer: Cementation by hard-water deposits, intergrowth of new minerals, and squeezing under the weight of additional sediment. Hard-water deposits are especially important in hardening coarse clastic deposits, especially sandstone and coarser. The finer-grained deposits are more controlled by compaction under additional weight, and intergrowth of new minerals. But all of these processes can contribute.

If you went swimming in the single channel of this river, and grabbed a sample of the river bank, what would you likely come up with? A) A mixture of clay, sand and boulders, called till. B) Sand, that can make really steep slopes such as are seen in sand castles. C) Boulders, that pile together to hold up river banks. D) Sand, that collapses to plug channels . E) Clay, that sticks together and can hold up steep slopes.

Answer: Clay, that sticks together and can hold up steep slopes. This is a meandering channel, and these normally are fairly deep and narrow, so the materials of the banks should be able to stick together and support a steep slope. Sand can be steep when damp, but slumps to nearly flat when wet, and boulders or too much sand plug streams and make a braided pattern, whereas clay can make very steep slopes.

If you went swimming in the single channel of this river, and grabbed a sample of the river bank, what would you likely come up with? A) Sand, that can make really steep slopes such as are seen in sand castles. B) Boulders, that pile together to hold up river banks. C) Sand, that collapses to plug channels . D) A mixture of clay, sand and boulders, called till. E) Clay, that sticks together and can hold up steep slopes.

Which of the following is NOT a job that geology graduates commonly get hired for: A) Cloning new biological organisms for use in international terrorism. B) Finding valuable things in the Earth. C) Helping understand the Earth system. D) Warning people about landslides, earthquakes, and other hazards. E) Teaching.

Answer: Cloning new biological organisms for use in international terrorism. Most jobs in geology involve finding valuable things: oil, clean water, ores, and more. But, geologists also teach and communicate in other interesting and entertaining ways, warn about hazards, and help understand the Earth system.

Which is younger: Fault J. Fault H. Unconformity K. Unconformity L. Fault I.

Answer: Fault H Unconformity L is cut by fault I, so is older than I. Fault I is cut by fault J, so is older than J. Fault J is cut by unconformity K so is older than K. Unconformity K is cut by intrusion G so is older than G, and intrusion G is cut by fault H so is older than H. Hence, fault H is the youngest.

Which is the oldest fault: I H J

Answer: I I is cut by J, so I is older than J. And with reference to K, both I and J can be shown to be older than H.

Sometimes, science and religion come into conflict. This is because: A) Science and religion can coexist just fine with a little effort, but sometimes choose not to do so. B) Science and religion must disagree.

Answer: Science and religion can coexist just fine with a little effort, but sometimes choose not to do so. Pope John Paul II said that the Catholic Church has no problem with evolution, and Baptist Jimmy Carter also supported evolution, so it is clear that religion and science can agree.

Geologic history involves learning the order of events in the past (which came first?), and, what happened. Part of "what happened" is reconstructing what the environment was like in the past. What is accurate about the human effort to learn about past environments? A) Sediments and sedimentary rocks tell us a little bit about whether the past environment was a lake or desert, but not much else. B) Sediments and sedimentary rocks reveal that our primitive ancestors of previous millennia survived on pizza and Pepsi. C) Sediments and sedimentary rocks provide no information whatsoever about the past. D) Sediments and sedimentary rocks provide much information about whether they were deposited in the ocean or on land, whether the climate was hot or cold and wet or dry, and more. E) Sediments and sedimentary rocks include almost no clues about past environments.

Answer: Sediments and sedimentary rocks provide much information about whether they were deposited in the ocean or on land, whether the climate was hot or cold and wet or dry, and more. Lake or ocean or sand dune or glacier, warm enough for crocodiles, wet enough for trees, and so much more—sediments and sedimentary rocks are books in which the details of the past are written.

Glaciers form where: A) Rocks are being raised by tectonic motions. B) Snowfall exceeds melting for a long enough time. C) The average temperature is well below freezing for a long enough time. D) Winters are really snowy for a long enough time. E) Melting exceeds snowfall for a long enough time.

Answer: Snowfall exceeds melting for a long enough time. Anyone from Erie can tell you that a snowy winter does not guarantee a glacier, and anyone from the permafrost of Siberia could add that cold does not guarantee a glacier. Many high mountains are free of ice, and some warm places are being raised tectonically. The way to make a glacier is to pile up more snow than melts.

Which is younger: Fault I. Unconformity L. The tree. Rock layer C. Rock layer D.

Answer: The tree The tree is growing on intrusion G, which can be shown to be younger than all of the others.

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