GEOSC 100

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Volcanoes of many different types can be observed at the surface of the Earth. Suppose you are looking at a hot-spot volcano. If you could see deep beneath that volcano, what would you find?

A rising tower of hot rock, coming up from below and perhaps from waaaaay below, down at the bottom of the mantle.

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?

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 water from rain soaks through the soil, the water typically:

Gains carbon dioxide (CO2) from the air and then gains more carbon dioxide in the soil, becoming more acidic.

The law that established the National Parks gave them a hard job, because it required that they:

Help people enjoy the parks today, but also save the parks for the future

Heating of some materials produces coal. With increasing temperature and time, one observes:

Peat, lignite, bituminous, anthracite.

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:

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.

In chemistry, the type of an atom (what element it is) is determined by:

The number of protons it contains in its nucleus.

The above Landsat image from NASA shows Cape Cod, Massachusetts. The short yellow arrow indicates new sand deposits, which have formed over the last decades. The long pink arrow indicates underwater sand deposits. The dotted blue arrow points to the great Outer Beach of the Cape. Based on material presented in this class, what is going on?

The ocean is eroding the blue-arrowed outer beach, and the yellow-arrowed end is growing more slowly, with some sand falling off to the pink-arrowed deposits and then off into deeper water, so the Cape as a whole is shrinking.

The above Landsat image from NASA shows Cape Cod, Massachusetts. This is a pile of sand and gravel out in the north Atlantic. The Cape has no large rivers, and is not especially close to any large rivers (the Connecticut and the Hudson are far out of the picture to the left). Looking along the far right-hand side of the Cape, the long white line is sand of the great outer beach (pink arrow), and sand deposits are prominent to the north and south (yellow arrows). What is going on?

The ocean is eroding the outer beach, and the yellow-arrow ends are growing more slowly, so the Cape as a whole is shrinking.

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:

The older layer was thrust over the younger layer by the forces of obduction.

Which is not accurate about the Grand Canyon, in Arizona:

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.

What is indicated by the arrows?

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.

Earthquakes can be caused in many different ways. The best interpretation of the planet's earthquakes is that:

The rare, deepest ones are caused by "implosion" as minerals in downgoing slabs of subduction zones suddenly switch to a denser arrangement, whereas common shallower ones are caused by elastic rebound of bent rocks when a fault breaks.

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?

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.

Dave has just informed everyone that the black rocks, which formed by cooling of a very hot lava flow, are much younger than the red rocks, which formed from sediments deposited in a lake. He has examined the red rocks and found that they have not been "cooked" by heat from the black rocks, so the red and black rocks must have been placed together after the black rocks cooled. And, he has examined the contact between red and black rocks and found that it is a fault that has been scratched by the motion of the rocks along the fault. It is likely that:

The scratches are nearly vertical, because the black rocks were dropped down along a pull-apart fault to lie next to the red rock.

Sea level can change locally for many reasons, but averaged over all of the oceans of the world:

The seas are rising, because warming is causing the ocean water to expand and mountain glaciers to melt.

In the image above, a stream from the land on the right enters the ocean on the left in the lower part of the picture, and another does the same near the top of the picture. What happened where the streams met the ocean?

The sediment carried by the streams settled out in the slower-moving ocean water, forming deltas that built up as they built out so that they still slope slightly downhill toward the sea.

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:

The sediment is thin near spreading ridges, and thicker away from the ridges.

Soil is produced by weathering of rocks. In the natural state of affairs, on a hillside covered by soil:

The soil thickness tends to a nonchanging value as production is balanced by removal, but you may have to watch for a while, as sometimes production may go faster and sometimes removal may go faster.

What probably happened in the above picture?

The tree started with its roots underground, but erosion washed the dirt away from them, so now they stick out.

Most landslides happen when:

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.

You build and maintain two biologically diverse terrariums that are identical in every way at the beginning, except that one is divided in half by an unbreachable glass wall. After some time (long enough for many generations to pass, but not long enough for much evolution to occur), it is most likely that:

The undivided terrarium will have more species than the divided one.

Above is a "beach" at Acadia National Park. The pieces are granite.

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.

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:

These rocks were buried deeply and squeezed in a continent-continent collision, and then brought to the surface as overlying rocks were eroded.

What do the ptarmigan and the marmot below have in common?

They are both standing on glacially eroded surfaces.

What happens to most living things, after they die?

They are recycled, usually by being "burned" with oxygen to provide energy for other living things, or to provide energy to fires.

Hot spots are important geological features. What is accurate about hot spots?

They are rising towers of hot rock, perhaps from as far down as the core-mantle boundary, bringing heat up to feed volcanoes.

The things that glaciers deposit include:

Till (which is unsorted) and outwash (which is sorted).

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:

Time=Depth of valley divided by Rate of valley lowering

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?

To the sedimentary rocks of western Pennsylvania to see bituminous, and to the metamorphic rocks of eastern Pennsylvania to see anthracite.

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:

Was scratched and polished by silt-laden river water, during carving of the Canyon by the Colorado River.

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:

Was scratched and polished by silt-laden river water, during carving of the Canyon by the Colorado River.

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?

Waves go slower in shallower water.

The great scientist Alfred Wegener proposed that continents have moved, while other scientists such as T.C. Chamberlin argued against Wegener. Wegener's ideas eventually won, and are now widely accepted, because:

Wegener's ideas did a better job of predicting the results of new observations and experiments.

Can a good geologist ever find a material that is somewhere between sedimentary rock and sediment, loose stuff somewhat stuck together but not really hard?

Yes, because sediment is changed to sedimentary rock by heat, pressure, and hard-water deposits, and intermediates exist.

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 down (which letter is closest to the arrow that is pointing in the direction you would have looked to see the ground when the dune was deposited)?

The best description of a scientist's job is that she or he:

invents new ideas, and shows that some ideas are false.

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 0.3 kilograms (0.3 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 0.3 kg/m3. If Spring Creek collects a layer of water 0.33 m thick from all of Happy Valley each year (0.33 m3 from each square meter or m2), and each cubic meter of Spring Creek water contains 0.3 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.) 0.33 m3/m2/yr x 0.3 kg/m3 = __________ kg/m2/yr.

.099

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 2600 kilograms per cubic meter (2600 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 2600 kg/m3 =_____________m/yr (note: your calculator probably shows a whole bunch of digits; just choose the answer below that is closest).

0.000038 (your calculator might also show this as 3.8x10-5 or something similar)

Total Pounds (or Tons) of CO2 Produced by U.S. Drivers per Year Calculation: Imagine for a moment that the CO2 behaved like horse ploppies, making a pile in the road, rather than wafting away in the atmosphere. How much would we have? Here are your necessary facts: There are roughly 140,000,000 cars in the country Each car averages 12,000 miles per year Each car is producing @ 1 pound of CO2 per car per mile How many pounds of CO2 are produced each year by U.S. drivers? To get this number, simply multiply the 3 variables above for this answer. This is a big number - one that cheaper calculators won't be able to handle. In this case, you'll want to come up with the number of tons instead of the number of pounds of CO2 . (2000 lbs = 1 ton). The formulas will look like this; Total Pounds of CO2 produced in a year by U.S. drivers: # of cars X # of miles per car X pounds of CO2 per mile Total Tons of CO2 produced in a year by U.S. drivers:(# of cars / 2000) X # of miles per car X pounds of CO2 per mile -- or -- Total Tons of CO2 produced in a year by U.S. drivers: # of cars X (# of miles per car / 2000) X pounds of CO2 per mile So, what do YOU come up with for this answer?

1,680,000,000,000 pounds / year (or 840,000,000 tons )

Gasoline is a remarkably interesting soup of hydrocarbons of various sorts, with bits of this and that added, but the average chemistry is not too far from being carbon and hydrogen, with two hydrogen atoms for each carbon. Burning involves combining gasoline with oxygen to make water and carbon dioxide. (Other things that are made in small quantities, such as carbon monoxide, are not as nice.) The chemical formula for burning gasoline can then be written something like: CH2+1.5 O2 --> CO2+H2O (If you don't like having one-and-a-half oxygen molecules, you can think of two hydrocarbons plus three oxygens making two carbon dioxides and two waters; it is the same thing, really.) In burning, each carbon atom, C, in gasoline eliminates two hydrogens and replaces them with two oxygens each carbon atom weighs 12 atomic mass units each hydrogen weighs 1 each oxygen weighs 16; So, CH2 starts out weighing 14 (12 from carbon and 2 from hydrogen), and CO2 ends up weighing 44 (12 from carbon and 32 from oxygen)—the weight has more than tripled. Rounding that off a little, the total weight of CO2 put out by a typical U.S. driver is three times larger than the weight of gasoline burned. To get the number of pounds of CO2 per year from a typical car, then, multiply your answer from the previous question by 3.

10,800 pounds / year

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.

11,000,000

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?

2 is upstream of the Glen Canyon Dam, and 1 is downstream of the dam.

The great extinction at the end of the Paleozoic Era that changed the living types on Earth and made way for the origin of dinosaurs during the Mesozoic Era occurred about:

225,000,000 years ago.

And how much does that gas weigh? Hint: Your previous answer for number of gallons per year, multiplied by the weight of gas as given previously, gives you the weight of gasoline burned per year in a typical car:)

3,600 pounds / year

Pounds of CO2 per Square Foot of Road per Year Calculation: There are about 15,000 square miles of paved roads in the U.S. (the roads are long and skinny, but if you took roads and made them into a giant tennis court, you'd have about 15,000 square miles), or about 15,000 x 5280 x 5280 = 420,000,000,000 square feet (rounding off just a bit). For this answer, then, simply divide the answer from the previous question (number of pounds of CO2 per year produced by U.S. cars) by the total highway square footage number above. Cheap calculators? You likely won't be able to type in the number of square feet; in that case, if you calculated a number of tons (T) in the previous question, you should do T x 2000 / 15,000 / 5280 / 5280, giving an answer very near to:

4 pounds per square foot / year

You start with 400 parent atoms of a particular radioactive type, which decays to give stable offspring. You wait just long enough for three half lives to pass. You should expect to have how many parent atoms remaining (on average):

Rising air expands and cools; sinking air is compressed and warms. Typically, the size of the temperature change is:

5oF/1000 ft change in elevation if condensation or evaporation are not occurring; 3oF/1000 ft change in elevation if condensation or evaporation are occurring

Rising air expands and cools; sinking air is compressed and warms. Typically, the size of the temperature change is:

5oF/1000 ft change in elevation if condensation or evaporation are not occurring; 3oF/1000 ft change in elevation if condensation or evaporation are occurring.

A gallon of milk weighs eight pounds, so you wouldn't try to carry three or four gallons home on your bicycle. Gasoline is a bit less dense than milk—oil floats on water—and 6 pounds per gallon of gasoline is about right. A typical U.S. "car" (whatever it is we drive—averaging somewhere between a Prius and a Hummer, and including a lot of pickup trucks and minivans) gets about 20 miles per gallon, and drives about 12,000 miles. So, how many gallons of gas per year?

600 gallons / year

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?)

833,333

In the first picture, 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 block of ice from the glacier fell into an outwash plain deposited by the glacier's meltwater streams, and the ice later melted to leave a lake, the lake filled with peat and other organic materials, and was later buried by sand dunes, with erosion of coastal bluffs now exposing the deposit.

The bowl-shaped feature in the foreground of the above photo is:

A cirque, a bowl gnawed into a mountain at the head of a glacier.

Near Aaronsburg, PA, a company wanted to start a limestone quarry, and planned to pump lots of water out of the ground to make things fairly dry near the quarry so it wouldn't fill with water. Concern was raised—would this affect the nearby trout streams? So, a little harmless dye was placed in a sinkhole next to the proposed quarry, and a fire-engine pumper added a lot of water to the sinkhole. How long did it take, or will take, for the dye to reach the trout stream?

A few hours to days.

This rock in the picture above was modified by:

A glacier, which scratched and polished the rock at A and plucked blocks loose at B, as the ice moved from A to B.

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 great unconformity, with sedimentary rocks above resting on older sedimentary rocks below.

What is indicated by the yellow lines in the image above?

A great unconformity, with sedimentary rocks above resting on older sedimentary rocks below.

Look at the picture above. What happened here?

A great volcanic explosion occurred, spreading material across the landscape and leaving a hole.

What can you learn about past environments from sediments and sedimentary rocks?

A huge amount, including whether the environment was land or water, whether it was warm enough for crocodiles or cold enough for ice, and much more.

Which of these materials is "hottest" in the sense that it is most likely to flow rather than to break (note that K stands for Kelvin, an absolute temperature scale in which zero is absolute zero and higher numbers mean warmer temperatures)

A material at 250oK that melts at 300oK.

Scientists often speak of consensus—the scientific community agrees that a particular theory is better than the competitors. What is such scientific consensus based on?

A number of different experiments by different people that all had outcomes that were predicted accurately by the favored theory and not by the competitors.

Which is more likely to contain reliable information?

A refereed article in a learned journal.

An unconformity is:

A time gap in a sequence of sedimentary rocks caused by a period of erosion or nondeposition.

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 was formed first, then B was glued together by hard-water deposits, then C was glued together by hard-water deposits.

Carbon dioxide, CO2, is an important greenhouse gas. Greenhouse gases warm the Earth primarily by:

Absorbing some of the infrared radiation emitted from the Earth.

Which of the following was probably important in contributing to extinction of most species at the same time the dinosaurs became extinct?

Acid rain, from sulfuric acid from the meteorite hitting sulfur-bearing rocks, and from nitric acid from the heat of the meteorite burning the air.

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:

An atom

A widely accepted scientific idea usually is based on:

An interlocking web of important experimental results or observations that support the correctness of the idea.

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?

An unconformity, where erosion occurred before the rocks above were deposited.

The picture above shows:

An upside-down dinosaur track.

Which of the following is commonly expected 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)?

Andesitic stratovolcanoes fed by melt from the slab being subducted.

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.

The picture above shows a beautiful specimen of Araucarioxylon arizonicum, a fossil tree from the Mesozoic rocks of Petrified Forest National Park. Based on the discussions of evolution in the class materials, it is likely that:

Araucarioxylon arizonicum is related to, but recognizably different from, trees still alive today.

Tsunamis

Are caused by earthquakes, undersea volcanic eruptions, or anything else that displaces a lot of water in a hurry.

Tsunamis:

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.

The volcanoes on the island of Hawaii (and the Loihi seamount, a submerged volcano to the southwest of Hawaii):

Are not located at a subduction zone or other plate boundary, but instead poke through a plate drifting over the Hawaiian hotspot.

Continents:

Are the "unsinkable" part of the solid Earth; although a little of a continent might go down, most continental material stays near the surface.

What geological processes have caused the Grand Canyon to be wider at the top than at the bottom?

As the river cuts down, the steep walls of the canyon experience mass movement (rocks fall, slump, creep or otherwise move off the walls and down to the river), so the top of the canyon is widening as the river deepens the bottom.

Regions with mountain glaciers that experience much surface melting in the summer typically are eroded:

At a faster rate than regions with streams but no glaciers.

In a glacier, the ice moves fastest:

At the upper surface, where ice meets air.

Using ordinary means (fire, sunlight, our digestive systems) we can take matter apart into smaller and smaller pieces, and the smallest pieces we typically produce are:

Atoms.

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?

B is pull-apart, C is slide-past, and A is push-together.

The recent changes in the amount of ice on Earth over time occurred:

Because changes in the Earth's orbit have caused changes in the amount of sunshine received during certain seasons at different places on Earth.

You are flying along the coast, and you observe a sort of dam or wall, called a groin, sticking out from the coast. Sediment has piled up on one side of the groin, with erosion on the other side. You can reasonably infer that:

Before the groin was built, sediment transport in the longshore drift was dominantly from the side with the sediment deposit to the side with the erosion, and the groin has interrupted some of this transport.

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?

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.

What do we know about the effects of humans on extinction of plant and animal species on Earth?

Both prehistoric and modern humans have been responsible for extinctions.

Hawaiian volcanoes, where they emerge above sea level, are:

Broad, gentle shield volcanoes, much flatter than stratovolcanoes such as Mt. St. Helens.

You are a geologist. While walking in the fog one day, you bang into a cliff. After rubbing your sore nose, you inspect the cliff, and see what is shown in the picture, in a one-foot-square area. You recognize that this cliff is made of "fossil sand dunes", with wind-blown sand that was later glued together by hard-water deposits. You are accompanied by a student, who is carrying your tea and crumpets for you. You sketch four arrows on the cliff, label them as shown, and ask the student which of the arrows was pointing up when the loose sand was deposited. Your student is brilliant, and correctly tells you the answer. The arrow that was pointing up when the loose sand was deposited is the arrow that is closest to:

You are still a geologist, still wandering around in a fog with a tea-and-crumpets-toting student, and you walk into another cliff. This one turns out to be a hardened lava flow. Again, you look at a one-foot-square region, sketch pink arrows with A, B, C, and D on that region, and ask the student which of the pink arrows was pointing up just after the lava flow hardened. To help the student, you draw four additional arrows on the cliff; these are light blue (turquoise) arrows, pointing at bubbles. (If you are not able to distinguish pink from light blue, the four pink arrows are very close to the four letters A, B, C, and D, and the four light-blue arrows are not close to the letters.) You suggest that the student consider the behavior of bubbles in a liquid. These bubbles are within the lava flow, and not in the crust on top of the flow that was chilled very rapidly by the air. Your student is brilliant, and correctly tells you the answer. The pink arrow (close to a letter) that was pointing up when the lava flowed in and slowly cooled is the arrow that is closest to:

Which is the correct age progression, from older (first) to younger (last)?

C, D, E, F, B

. Clicking on the blue number after "Times Cited" will tell you all of the papers who have cited Leo Peter's paper, and thus are relying on it. Click on the "Times Cited" number. Fellow graduate student A.P. Rathbun cited the Leo Peter's paper in 2008. Who was the second author on Andy Rathbun's paper?

C. Marone

Which formula most closely describes the process by which plants make more of themselves:

CO2 + H2O + energy → CH2O + O2

The idea that human activities will cause global warming is well over a century old now. The United Nations has been sponsoring studies of this idea for almost two decades. The assembled scientists have concluded, with high confidence, that:

CO2 levels in the atmosphere have been rising, warming the planet a degree or so, and burning all the remaining fossil fuels likely will raise the Earth's temperature many degrees or more.

You watched online as Dr. Alley carved a sand canyon with his finger. Based on what you saw, and on what you know about slopes, stability, mass movement, etc., if a landslide happened someplace last week, you would tell the neighbors:

Care is required; landslides are removing instabilities and moving things towards stability, but a second landslide, or a flood, or other problems are real possibilities.

During the most recent ice age:

Central Pennsylvania was just beyond the edge of the Canadian ice.

Clay consists of new minerals commonly formed by:

Chemical weathering of feldspar (feldspar contains silica, aluminum, potassium and other things)

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?

Clay, that sticks together and can hold up steep slopes.

Chemical weathering of a continental rock such as granite in a climate such as that of Pennsylvania or other places where a good bit of rain falls, produces:

Clays and rust, that do not wash away easily, and soluble ions, that do wash away easily

Regarding global warming, most scientists (including those who have advised the United Nations through the Intergovernmental Panel on Climate Change) agree that if we continue to burn fossil fuels at an accelerating rate:

Climate changes will primarily hurt poor people in warm places, but the climate changes are primarily being caused by wealthier people in colder places.

Among fossil fuels:

Coal is made by heating of woody plant material, and oil is made by heating of algae.

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?

Condensation of water vapor to form clouds and rain releases heat that was stored when the water evaporated.

Which is not part of our modern view of geology?

Convection in the Earth primarily occurs in the lithosphere, and not in the deeper rocks.

Heat is moved around by convection, conduction and radiation (and by lemmings carrying space heaters, if lemmings ever carry space heaters). Which statement is more nearly correct?

Convection moves heat efficiently through the soft, hot rocks of the Earth's mantle, but is not efficient at moving heat through the space between the Sun and the Earth.

Considering long-term averages, and assuming that we don't deploy space-based defenses against incoming meteorites, a reasonable estimate of the chance of an average U.S. citizen being killed by the effects of a meteorite or comet impact is that this risk is about the same as the chance of being killed by:

Crash of a commercial airplane.

The processes that made Death Valley 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. Choose the best answer: what are they doing to the valley?

Death Valley is getting wider and deeper.

Glaciers move by

Deformation within the ice, and sometimes sliding over materials beneath or deformation within materials beneath.

Type "Alley RB" into the author space on the Web of Science. You will find lots of pages of refereed scientific literature that Dr. Alley has worked on. What was he publishing on in 1991? (Hint: the older ones are near the back, so use the "page" box near the top in the center to go there.)

Deforming-bed origin of southern Laurentide till sheets, and changes in the West Antarctic ice sheet.

When considering the land surface:

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.

The volcanoes of the island of Hawaii eventually will:

Drift off the hot spot and cease to erupt, while a new volcano grows to their southeast.

To get gas from the Marcellus shale, drillers:

Drill into and then along the shale, and then pump in high-pressure fluids to fracture the rock and release the gas.

Some eruptions come out of volcanoes really rapidly and shoot really high because:

Dropping pressure as the melt rises allows volatiles including water vapor and carbon dioxide to make bubbles that lower the density and make the melt rise even faster.

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?

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 material is added to their edges at subduction zones.

Look at the picture above, from the coast of Olympic National Park. What happened here?

Earthquakes knocked loose undersea muds that raced down the slopes of the west coast into the subduction zone, making rocks that were then scraped off the downgoing slab to make part of Olympic National Park.

Heat transfer by conduction is:

Efficient over short distances but inefficient over long distances.

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:

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).

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:

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).

Which of the following is not a part of the modern theory of evolution?

Evolution proceeds in the direction desired by members of a generation.

Which of the following is not a scientifically accepted statement about the occurrence of transitional forms in the fossil record?

Evolutionary theory shows that many lineages should have developed by "Ford Mustang" evolution without transitions.

If you are drilling a well to reach water, you usually will have to drill:

Farther into the ground to make a deeper well on a ridge than in a valley.

Which is older:

Fault I.

When humans build or raise levees along big rivers such as the lower part of the Mississippi, we are likely to cause:

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.

Your job depends on you finding the best available information on a particular technical topic. Where should you concentrate your search if you want to do it right and keep your job?

Find and study refereed scientific articles in learned journals.

The jobs of geologists include:

Finding valuable things in the Earth, warning about hazards, learning how the Earth works, and educating and entertaining people.

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:

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.

Sedimentary rocks composed of clasts or chunks are usually subclassified by geologists based on:

Grain size—rocks made of big pieces are given different names than are rocks made of little pieces.

Which correctly gives the order of the faults, from youngest (first) to oldest (last):

H, J, I

The Mississippi River:

Has built a delta, which is several miles thick at its thickest point, from near St. Louis, MO to the Gulf of Mexico over millions of years.

The glacier shown above:

Has retreated, because a decrease in snowfall to the accumulation zone (A) or an increase in melting of the ablation zone (B) occurred.

Volcanoes in Death Valley:

Have erupted recently (within the last centuries or millennia), showing that hot rock occurs at shallow depth beneath the valley.

Which of the following is not part of the evidence that the odd layer marking the extinction of the dinosaurs was caused by a large meteorite impact?

High concentrations of iron found in the layer.

High temperature and pressure tend to favor flow rather than breakage, so it is surprising that large, very deep earthquakes are sometimes observed, occurring in warm places where the pressure is high. What is accurate about these rare, deep earthquakes?

Yellowstone is in some ways similar to Hawaii. This is because both are:

Hot spot volcanic regions

The consensus of the world's climate scientists, as generated by the UN-sponsored Intergovernmental Panel on Climate Change (IPCC), is that:

Human activities have raised CO2 levels in the atmosphere, warming the planet, and the changes so far have been small compared to the changes that are likely over the next centuries unless we humans alter our behavior.

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?

I is older than the unique layer, and thus sat below the unique layer in the sediment on the sea floor.

Icebergs float in water and continents float above the mantle because:

Icebergs/continents are less-dense than the stuff they float in.

What is one of the main, common-sense ideas that geologists use to learn what happened first and what happened later in geologic history?

If you see a push-together fault cutting a clastic sedimentary rock, you know that the sediment was deposited, and then broken by squeezing, because something must exist before you can break it.

Given the materials presented in this class about the formation of caves, it is likely that most large caves are formed:

In limestone in moist climates.

The Paleozoic:

Is "old life", the age of shellfish.

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:

Is alternately toward and away from the shore, causing little net change.

You get in your Magic School Bus, drive down the throat of a volcano, and find that you are driving through melted rock that does not make lumps but flows more easily than does most melted rock. It is likely that the melted rock you are driving through:

Is especially rich in water and carbon dioxide compared to most melted rocks.

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:

Is more than about one-hundred-million years old.

What is accurate about peer review of scientific papers?

It provides quality control by eliminating many mistakes.

The above picture is from the Escalante-Grand Staircase National Monument. The pink arrows point along some interesting features. What are they?

Joints, formed when the sedimentary rocks were broken by physical-weathering or other processes.

The above picture is from the Escalante-Grand Staircase National Monument. The pink arrows point along some interesting features. What are they?

Joints, formed when the sedimentary rocks were broken by physical-weathering or other processes.

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 is written history?

Just over the thickness of a sheet of paper.

The above picture shows a region a bit under a foot across, in a cliff in Red Canyon, just west of Bryce Canyon National Park. The rocks in the picture are the same as the rocks at the bottom of the beautiful Bryce Formation, the pastel rocks in Bryce Canyon. The red arrows surround a very interesting, reddish clast. What is the geological interpretation of this picture?

Many older rocks, some with interesting histories, were rounded in a river, then mixed with sand and glued together by hard-water deposits; the resulting rock layer was broken into pieces, which were rounded in a stream, mixed with other rocks and sand and glued together by hard-water deposits, and the resulting rock layer was raised out of the river, and eroded to yield the modern outcrop.

In the picture above, the dark stripes on the surface of the glacier are:

Medial moraines, rocks picked up from points where tributary glaciers flow together.

What sort of rock is pictured above?

Metamorphic; The rock separated into layers as it was cooked and squeezed deep in a mountain range.

What sort of rock is the dark material very close to the pink granitethat Dr. Alley is pointing to in the picture above?

Metamorphic; The rock separated into layers as it was cooked and squeezed deep in a mountain range.

A place such as central Pennsylvania, home of Penn State's University Park campus, is fairly typical of the world in terms of rainfall. What happens to the rain that falls on central Pennsylvania each year?

Most of it is evaporated.

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?

Most of the damage is done by the few, big earthquakes.

Weathering attacks a granite in Pennsylvania or Washington, DC, or a similarly rainy place. The feldspar grains in the granite primarily:

Mostly make clay that stays in the soil for a while, although some chemicals also dissolve and wash away to the ocean.

Major differences between Mt. St. Helens and Hawaiian volcanoes include:

Mt. St. Helens is a medium-to-high-silica stratovolcano, and Hawaii has low-silica shield volcanoes.

Much less than the thickness of a sheet of paper.

Dr. Alley has helped drill many holes in ice sheets. Special tools can be lowered down the holes on cables, and tracked to learn the shapes of the holes. Initially, the holes are straight up and down. Years later, the holes are bent, because the ice in the ice sheet is flowing. What does it mean to say that the ice is flowing?

Much like rocks in the mantle or iron heated by a blacksmith, the ice is almost hot enough to melt, and deforms as gravity pulls on it, without breaking into loose chunks.

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?

Near the bottom, where the river has cut through rocks that were cooked, squeezed, and partially melted deep in an old mountain range.

There may be more than one S. Anandakrishnan, or R.B. Alley, in the world. One way to tell them apart is to check the address, which is also listed in the Web of Science. The Web of Science actually tries to help you. If you make sure to click the tab near the upper left that says "Web of Science" rather than "All Databases" before you do the search, it provides a "View Distinct Author Sets" option. In this case, don't mess with that. In the Web of Science, just search on Anandakrishnan S, and find the paper by Balasubramanian and others from 2004. Is this the same S. Anandakrishnan from Penn State's Geosc10 that you know as Dr. A? (If you find a Penn State address in the list below, you may assume that it is the same Dr. A you know, and if you don't find a Penn State address, you may assume that the author is a different S. Anandakrishnan; we won't make you click through other Dr. A references to make sure)

Extinction of existing species:

Occurred at a low level throughout geologic history, punctuated by mass extinctions when many types were killed over very short times.

At current rates of use, and at prices not greatly higher than those of today:

Oil will run out in a century or so, and coal will run out in a few centuries.

Rocks in continents are on average much older than sea-floor rocks. The likely explanation is:

Old sea floor is recycled back into the deep mantle at subduction zones at the same rate that new sea floor is produced, but continents are not taken into the mantle and so remain on the surface for a long time.

Limestone, the type of rock most likely to contain caves, is made up of:

Old shells, or pieces of old shells, pressed together.

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:

Orange and red indicate loss of wetlands over time, whereas yellow and green indicate gain of wetlands over time.

What is accurate about seismic waves moving through the Earth?

P-waves (also called push-waves or sound waves) move through both solids and liquids.

Some scientific journals are now on the Web, so some Web sites (a VERY small percentage of the total) are now refereed and part of the scientific literature, but almost all Web sites are not. Wikipedia may be a nice shortcut to learn a lot of things, but it is NOT refereed in the ordinary sense; it (like this textbook) is no better than a secondary source. As a general observation, much of what is published in books is fiction, including much of what is published in supposedly non-fiction books. Books are typically not reviewed and so are not as reliable as the scientific literature. Because publication of a book is expensive, some quality control is used by publishers, although typically not enough. Because Web sites are so incredibly cheap, they experience much less quality control and all should be suspected of propagating nonsense. The Web is a great way to transmit words, pictures, and numbers, but much or even most of the transmitted material is misleading or wrong. Be wary of all Web sites! Make them prove reliability to you before you believe them. Click on the link to download the two articles. Which one is refereed?

Paper #1, "Pacific Ocean and Cenozoic Evolution of Climate"

The pictures show famous volcanoes, that are discussed in the class materials. Which statement is most accurate about these?

Picture II shows a hot-spot-type shield volcano, and picture I shows a subduction-zone-type stratovolcano.

Many plants are hard to get along with. Imagine crashing pell-mell through a thicket of devil's club (pictured above), in coastal Alaska, to get away from a charging brown bear. The native people use devil's club for medicinal purposes. We now know that:

Plant protection by thorns is supplemented by 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 geologic time scale is, starting with the oldest and ending with the youngest:

Precambrian, Paleozoic, Mesozoic, Cenozoic.

Ignoring good manners, you start rooting around in the nucleus of a poor, unsuspecting atom, to see what is in there. What are you most likely to find?

Protons, usually with some neutrons hanging around among the protons.

The picture above shows a view in the Earthquake Lake region just northwest of Yellowstone. The ramp or slope (often called a scarp) formed in an earthquake.What likely happened?

Pull-apart forces pulled the rocks apart, making the break, and allowing one side to drop relative to the other.

What tectonic setting is primarily responsible for producing Mt. St Helens?

Push-together Subduction

This is a photo of a road cut through a mountain called Sideling Hill, in Western Maryland. What happened here?

Push-together forces when Africa and Europe ran into the Americas bent the rocks, which later were exposed at the surface by erosion.

What tectonic setting is primarily responsible for producing Crater Lake?

Push-together subduction.

What tectonic setting is primarily responsible for producing Olympic National Park as well as the hills on which San Francisco is built?

Push-together subduction.

The main types of boundaries between different lithospheric plates are:

Push-together, pull-apart and slide-past.

National Parks are:

Regions containing key biological, geological or cultural resources that have been set aside for the enjoyment of the present generation and future generations.

Dr. Alley took this picture in central Utah. The rock shown started out as soft sediment deposited in Lake Flagstaff, at about the same time and just a little north of the lake in which the limestones of Bryce were deposited. These lakes grew and shrank with changing climate, often forming muddy flats that dried and cracked to make mud cracks, which then were filled and covered by more sediment as the lake grew again. The pocket knife shows you that this sample is a foot or two in length. The sun was high and hot when the picture was taken, but slanting in from the left as shown, and we have provided arrows to direct your eye to a couple of shadows. Dr. Alley placed this sample so it could be photographed easily. Did he place it upside-down (you are looking at the side that was down when the sediment was soft) or right-side up (you are looking at the side that was up when the sediment was soft)?

Right-Side up

The picture above shows a muddy limestone that was deposited in shallow water of a lake. The pocket knife is sitting on a high region of the rock. The pink arrow points along a low trough or groove in the rock, and several other such grooves are evident. The rock is:

Right-side-up; you are looking at the side that was facing up toward the sky when the rock was deposited.

Geologically speaking, the water table:

Rises during or soon after rainstorms as spaces fill up, and sinks during droughts as water drains away.

You decide to get "back to nature", so you dig a well in your back yard in the limestone rocks there, install a hand pump, and pump the water from your well into a basin to which you add a little soap when you want to wash dishes. After a while, you notice white scum on your glasses, which gets worse and worse with time. This probably is:

Rock that had been dissolved in the water, and that probably is building up inside your pump and elsewhere as well.

Geophysical evidence indicates that convection is occurring in the Earth's mantle. What is the most likely physical explanation for why convection can occur in the mantle?

Rocks deep in the Earth expand and so become lower in density and tend to rise as they are heated, and the deep rocks are warm enough to flow slowly even though they are mostly solid.

When discussing earthquakes that happen in the upper part of the Earth's crust, geologists believe that most are caused by elastic rebound. This means:

Rocks on opposite sides of a break, or fault, move in opposite directions, get stuck against each other for a while, bend, then "snap back" when something breaks or gives along the fault.

During weathering, iron in minerals typically:

Rusts, becoming part of the soil, later to be transported as solid particles to contribute to sediment in the ocean.

What is accurate about seismic waves moving through the Earth?

S-waves (also called shear-waves) move through solids but not liquids.

In the two pictures above, I and II, show traces of former life in rocks from the Grand Canyon. Each is "typical";the rocks near sample I contain fossils similar to those shown in sample I, and the rocks near sample II contain fossils similar to those shown in sample II. It is likely that:

Sample I is from higher in the cliffs of the Grand Canyon, and sample II is from much lower, nearer to the river

If you went swimming in one of the channels of the river pictured above, and grabbed a sample of the river bank, what would you likely come up with?

Sand or gravel, that collapses to plug channels.

Sometimes, science and religion come into conflict. This is because:

Science and religion can coexist just fine with a little effort, but sometimes choose not to do so.

Opinion polls show most residents of the US do not believe they understand science very well, but they do favor more government support of science. Why do most US residents favor government support of science?

Science has helped make our lives healthier, wealthier, easier, safer, etc., and people hope that more funding of more science will provide even more health, wealth, ease, safety, etc.

Years may pass with no major damage to the US mainland from hurricanes, but other years bring huge damages. A terrible event happened in 2005, when levees around New Orleans failed in the rising waters of Hurricane Katrina. More than 1400 people died, and the damages were in the neighborhood of $300 for each person in the US, or about $100 billion. As discussed in the text, history shows that:

Scientists and serious planners had warned about such an event for decades, based on the known size of hurricanes and the sinking of the Mississippi Delta and much of New Orleans.

The US government, and most other governments of the world provide support for scientists but not for astrologers, palm readers, or telephone "psychics". Why do governments support scientists?

Scientists help humans do useful things, which makes the humans healthier, wealthier, etc., and governments often like to support health and wealth.

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:

Sculpting of the rocks by a glacier, which flowed from the left to the right.

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:

Sea-level rise as the last ice age ended flooded river valleys to form bays, and sediment now is deposited in these bays rather than being delivered to beaches.

Think about Pennsylvania, or other places in the eastern US. What is accurate:

Sediment is accumulating in a few places, with erosion in most places, and this has been the pattern for a long time, so the geologic record in any township or similar-sized area is notably incomplete, and you need to combine observations from many places to get a reasonably complete geologic record.

In the picture above, the yellow arrow points at a jetty, a sort of sea wall or groin or dam, that was constructed along the coast of Washington. A likely interpretation of what you see here is

Sediment transport is typically from the right, causing deposition to the right of the jetty but erosion to the left

In the picture above, the yellow arrow points at a jetty, a sort of sea wall or groin or dam, that was constructed along the coast of Washington. A likely interpretation of what you see here is:

Sediment transport is typically from the right, causing deposition to the right of the jetty but erosion to the left

Evidence that there was much more land ice about 20,000 years ago than there is now includes:

Shells of creatures that lived in the ocean about 20,000 years ago indicate that the ocean water was especially isotopically heavy then

Dinosaurs once stomped across the Yukon, leaving tracks in mud that were buried in more mud and hardened to stone. Some may have been turned on end or turned over by mountain building; others were split apart and turned over by humans looking for dinosaur tracks and putting them in museums. The light was shining in from the upper right, as indicated, making lighter-looking and darker-looking places depending on whether they were facing the light or in shadow; we have indicated a shadow of the human glove and of the dinosaur track to help guide your eye. Are you looking at the side that was down when the sediment was soft, or the side that was up?

Side that was down

The picture shows hard stone that was once soft sediment, from the Tonto National Monument, Arizona. Examination of the sample tells a geologist that mud cracking was occurring where the sample formed. When the picture of this sample was taken, the light was shining along the arrow, as shown, making shadows, some of which are indicated by the arrows. Are you looking at the side that was down when the sediment was soft, or the side that was up

Side that was down

The dominant large animals on Earth today are mammals. Before the giant meteorite impact 65 million years ago:

Small mammals coexisting with the dinosaurs 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.

A glacier that had not changed its size or shape for a long time is now getting shorter. What does this tell you?

Snowfall has decreased, or melting has increased, or both.

What causes the great majority of earthquakes?

Stick-slip behavior across faults

What is accurate about the scientific results learned by counting tree rings?

Study of tree rings and associated geology shows that the Earth is more than 12,429 years old.

Beaches change as seasons progress. 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):

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.

Suppose that CO2 in the atmosphere was held at a constant, natural level for a few thousand years. Then, CO2 was added to double the atmospheric level rapidly, and this new, doubled level was maintained for a few thousand years. What was the most likely change in the typical average temperature of the planet?

Temperature before the increase in CO2 was a few degrees lower than temperature after the increase.

The Earth has a fascinating history, which this class has just begun to explore. Which is more nearly correct, according to the scientific interpretation presented in the text?

The Earth formed about 4.6 billion years ago, well after the Big Bang, as materials made in stars fell together to form the planet.

The scientific study of the origin of the planet has taken a lot of effort, and still generates much discord outside the scientific community although almost no discord within the scientific community. The scientifically accepted history is:

The Earth formed from older materials that fell together under gravity about 4.6 billion years ago.

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?

The Earth would end up a few degrees warmer than before the human influence, because positive feedbacks would amplify the original change.

If we could artificially double the CO2 content of the atmosphere and then hold the CO2 content at that level for a thousand years, the most likely effect would be:

The Earth would warm a few degrees, and then the temperature would stabilize at that new, warmer level.

There is a deep trench in the sea floor off the Marianas volcanic arc of explosive, andesitic, Ring of Fire volcanoes in the South Pacific, but the water is not deep off the coast of Oregon and Washington near Mt. St. Helens and the Olympic, because:

The Marianas, Oregon and Washington have had the sea floor bent downward by subduction to make trenches, the trench off Oregon and Washington is filled by sediment eroded from the nearby continent, but the Marianas don't have a nearby continent and so the trench there is not filled with sediment.

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:

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

The size of a typical sandy beach, averaged over a few decades, is usually controlled by:

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

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:

The beach to lose the new sand over the next year or years, as waves and currents move the sand back to deeper water.

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?

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.

The picture above illustrates what scientific principle?

The equator is hotter than the pole because the sun hits the equator directly but the sun hits the pole a glancing blow

The picture above shows a glacier in eastern Greenland, in the world's largest national park, flowing from mountains at the top of Jameson Land (at the top of the picture) toward the lowlands of Kong Oskar Fjord (just out of the picture at the bottom). Based on what the picture shows, what has happened over the last century or so?

The glacier has become shorter, because of a decrease in snowfall to the accumulation zone (A) or an increase in melting of the ablation zone (B).

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:

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.

On the Richter scale of earthquake intensity:

The ground is shaken 10 times more by a magnitude-8 quake than by a magnitude-7 quake.

Great Rock really is a great rock on Cape Cod, as shown by Dr. Alley's relatives for scale. The picture doesn't even show all of the rock above ground, and there is as much rock below ground as above. Great Rock sits well north along the Cape, just inland of Coast Guard Beach. Most of the Cape there is sand and gravel. So why is the rock there?

The ice carried the rock here—glaciers carry big as well as little rocks, and can leave big ones even if most of the material carried by the glacier is then sorted in outwash.

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. This actually is related to Death Valley, although these rocks are a good bit east of Death Valley. As described by Dave Janesko in the online video, what happened here?

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.

Look at the picture above. Here is new land forming in Hawaii, where lava enters the sea. What is happening here?

The lava flow has cooled on the sides and is draining out the middle. Eventually, if more lava is not supplied at the other end of the tubes to replace the lava that is draining out, the lava tubes may empty and leave caves.

What is accurate about a typical volcano formed by eruptions from a hot spot?

The lava of the volcano is mostly basaltic in composition, with gradual sides where the volcano projects above sea level, but steeper sides on undersea portions.

Which is accurate about the Earth?

The lithosphere normally breaks, and the asthenosphere normally flows.

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?

The low bluffs show that erosion has been occurring as waves hammer the shore, and the bar shows that longshore transport is moving the sediment from that erosion along the shore.

What type of mass movement moves the most material, averaged over the Earth's land and over long times?

The many, small events move the most material.

The picture above shows a hillslope in Greenland that is about ½ mile across. The hill slope towards you, so the lowest part of the hill is at the bottom of the picture, and the highest part is at the top of the picture. What is likely to be true?

The materials on the hillside are moving toward you at an inch or so per year.

Large rivers have many interesting features, including:

The natural levees, formed when flood waters leaving the channel slow down and drop much of their load near the channel; beyond the natural levees is the flood plain, where much of the rest of the mud in a flood is deposited in a thin layer.

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 statement below describes something indicating that the region is much older than calculated so far in this exercise? Two of the five answers are correct; pick one of the correct ones for full credit.

The rocks needed to be deposited, hardened, and bent before being eroded, and all of that took time.

In the bottom of Death Valley, you will find layers of gravel deposited by rivers. Based on materials presented in class, what is a likely explanation for this occurrence of river gravels in the valley bottom?

The valley was dropped relative to the mountains by faulting, and rivers now are carrying gravels down from the mountains into the valley and depositing the gravels at the valley bottom.

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.)

The water would be up around your waist or chest, but you'd still be able to breathe.

What is accurate about the planet's climate system?

The wind blows because heating near the equator drives convection cells in the atmosphere, and the winds appears to curve to the left or right over the surface of the planet because of friction produced by the spherical planet's rotation beneath the atmosphere.

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:

To be buried by sediment.

In the image above, (source: http://museum.gov.ns.ca/fossils/gallery/specimen) there is a chunk of limestone containing shell fossils, now displayed in a museum. The living clams died, the individual valves came apart so you have single shells like ( and not double shells like (). Waves deposited the shells on a beach, they were then glued together with other things to make the rock, and the rock was collected and brought to the museum. A bright, concentrated light was brought in to illuminate the chunk of limestone for the picture, and the light is shining along the arrow, from the upper right. Are the shells the way they were deposited, or, after the shells were glued together to form the rock, has the rock been turned over?

Turned over.

A nighttime picture of Earth shows human-controlled lights spread across most of the land surface, and a few out in the ocean on ships. In round numbers, humans (and the things we grow, or the pets we live with):

Use almost 50% of everything the world makes available and that we find useful.

Scientists collaborate a lot. The Web of Science tells you who all the coauthors are. Search on Dr. A (Type "Anandakrishnan S" into the author box of the search page). Notice that many of the entries list a few authors followed by "et al." (which stands for "et alia" and means "and others" in Latin). If you click on the blue title, you'll see a list of all of the authors. So, who was Dr. A co-authoring with in 1995?

W.R. Kapsner, C.A. Shuman and C.R. Stearns, among others.

The "Law" of Faunal Succession:

Was developed by an engineering geologist to aid in construction projects.

In the picture above, Dr. Alley is on the South Rim of the Grand Canyon. What problem with the Canyon is he discussing?

Water is being pumped out of the ground on the plateau south of the Canyon, and used by humans and evaporated or dumped in streams, so the water does not flow to the springs in the Canyon.

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?

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.

Old, cold ocean floor sinks at subduction zones. Why does this cause melting to feed volcanoes?

Water taken down subduction zones lowers the melting temperature in and near the slabs.

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:

When the proto-Atlantic ocean closed, at a push-together boundary.

At the beach, you can build really good sand castles:

When the sand is damp, because water is attracted to sand grains and to other water; thus, pulling sand grains apart when damp requires "breaking" the water, which is not easy.

You are dating a lava flow by the potassium-argon system. However, the offspring in this system are leaking out of the minerals. Which is accurate?

You will think that the lava flow is younger than it really is, but you will be able to detect the error by comparing concentrations of offspring from the edges and centers of grains.

If you could drill a hole straight to the center of the Earth, and keep track of what the hole is going through, you would find:

You would go through one sort of material, and then a different, denser material, and then a still-different, still-denser material, because the planet is made of concentric layers, sort of like an onion.

The diagram above 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. Referring to the rocks you see here ......Which is the oldest sedimentary rock layer?

Among features A, D, E, and O, which is the oldest?

feature E

Among features G, H, I, and J, which is the oldest?

feature I

Among features J, K, L, and P, which is the oldest?

feature K

Among features E, F, J, M, which is the youngest?

feature M

Among features C, D, M, O, which is the youngest?

feature O

Now, imagine that instead of CO2, our cars putout horse ploppies that fell on the road. U.S. cars would be delivering the number of pounds of horse ploppies you just calculated, each year, to each square foot of paved road in the country. The CO2 from our cars, if turned to horse ploppies, would make a one-inch-thick layer spread across all the paved roads in the entire country each year. Just take a moment and think of this—what would happen if you stomped on the accelerator in an inch of recycled hay? How about braking? After a few decades, would all the roads look like pickup-truck commercials, with giant sprays of something like mud coming off the tires? Would you enjoy being a pedestrian? Would joggers switch to cross-country skiing? To get total U.S. CO2 production, you need to multiply again by about 3—we heat and air condition our homes, etc., as well as driving our cars, and most of the heating and cooling comes from fossil fuels, too. So, spread that inch of horse ploppies across your living-room carpet, and across every other living space in the nation. Put differently, the average American generates 22 tons of CO2 per year. (Compare this to a bit over half a ton per person per year of solid waste put out in garbage cans to go to landfills.) With about 5% of the world's population, we are generating about25% of the world's CO2. If you had an inch-thick layer of horse ploppies each year on every square inch of paved road in America, you very clearly would smell it everywhere—the volatile organic molecules wafting off the mess would quickly be blown around the country and the world. We don't smell the CO2, but it is everywhere, building up steadily in the atmosphere, changing the climate... and we humans clearly are influential enough to do this. So, for you alert readers playing along at home, how thick would the layer be if all the CO2 released by U.S. cars were converted to an equivalent weight of horse ploppies and spread uniformly across all the paved roads in the U.S.?(you've already seen this answer several times, actually, so for those paying attention, consider this your reward)

i nch

Which is younger:

tree

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