GEOSC 10 PSU

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.

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:

Buettneria is related to, but recognizably different from, species still alive today.

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

If the body of an adult living thing is changed by its environment, those changes usually are passed on biologically to children.

You hear an astronomer on the evening news, pointing out a coming alignment of planets and predicting that the extra gravitational attraction is sure to trigger a huge earthquake in California during the few hours of alignment. Based on what has been covered in this class, a reasonable approach is to:

Ignore it; although gravitational forces such as tides and planetary pulls might possibly exert a very small effect on earthquakes, no one has successfully predicted the where-and-when of earthquakes.

The gas from the Marcellus shale:

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.

What is accurate about the scientific theory of evolution today?

It is being applied successfully in the real world in many ways, including helping fight new disease organisms, and even guiding the thinking of computer scientists.

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

"Impact winter" caused when tiny pieces of dust or other materials, which were put in the air by the impact, blocked incoming sunshine for months or years, after larger pieces had fallen back to Earth.

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):

"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."

Pictures 1 and 2 show two very different looking rivers. What can you say about them?

1 is a meandering stream with clay-rich banks, and 2 is a braided stream with sandy or gravelly banks.

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.

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):

50

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

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 (pointing up arrow)

You put some atoms together, and they share or trade some electrons. What just happened was:

A chemical reaction.

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.

Acadia National Park has a long, rich and varied geologic history. The large island marked "I" in the middle of the above picture is composed of resistant granite from the long-ago closure of the proto-Atlantic. However, the shape of the island was formed by much more geologically recent processes (within the last 100,000 years or so). What is primarily responsible for the beautiful shape of the island?

A glacier flowed over the island, moving from left to right, smoothing the rocks encountered first and plucking rocks free from the other side.

The above picture shows:

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.

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.

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.

The picture above shows:

A right-side-up dinosaur track.

You see a hot-spot volcano on the surface of the Earth. What is under this volcano?

A rising tower of hot rock from deeper in the mantle, and perhaps all the way from the bottom of the mantle.

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.

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 river-built deposit that is several miles thick at its thickest point, and extends from near St. Louis, Missouri to the Gulf of Mexico.

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.

There are many greenhouse gases, including carbon dioxide (CO2), methane (CH4). and vaporized water (H2O). These and other greenhouse gases warm the Earth primarily by:

Absorbing some of the infrared radiation emitted from the Earth.

Humans (and our crops and pets and farm animals) now use:

Almost half of the things the planet makes available and that we like to use.

What is accurate about the planet's climate system?

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.

If North America and Asia continue drifting towards each other across the Pacific at their modern rates, they must someday develop what?

An Appalachian-type or push-together obduction boundary.

Chemists recognize many different elements, such as gold, or oxygen, or carbon, or iron. Suppose you got some iron, and started splitting it into smaller pieces. The smallest piece that would still be called "iron" would be:

An atom

The picture above shows Telescope Peak, towering above Death Valley.The straight edge of the alluvial fan in the foreground is:

An earthquake fault, where the valley has dropped relative to the mountains.

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?

An ice block from the glacier was buried in sand and gravel, then melted to make a lake that filled with organic material.

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 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)?

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.

Heating of some materials produces 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.

Tsunamis:

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

Most earthquakes:

Are caused when rocks on opposite sides of a break, or fault, in the Earth's crust move in different directions, and the fault is poorly lubricated, so the rocks along the fault get stuck for a while and bend their neighbors before breaking free and moving.

Transitional forms between distinct types (species) of different ages in the fossil record:

Are common for commonly fossilized types, but rare for rarely fossilized types.

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

Are loosened from the rock but don't change much, staying in the soil as quartz sand.

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.

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.

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 is up, B is right, C is down, D is left]

B

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.

Convection occurs:

Because hotter things are less dense and tend to rise.

The above picture shows ocean in the upper right, a beach, andland (lower left). The red dashes trace the crest of a wave. Wavesmove perpendicular to their crests. What principle is illustrated by the picture?

Because waves go slower in shallower water, waves turn and move almost directly towards the beach, but the little bit of along-beach motion remaining drives longshore 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.

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?

C

The great disaster at Lake Nyos in Cameroon, Africa, in which hundreds of people died, occurred when this material was released from the volcano:

Carbon dioxide (CO2) that suffocated the people.

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

CO2 + H2O + energy → CH2O + O2

Tsunamis:

Can be predicted with some accuracy seconds to hours before the waves strike in most cases, allowing quick warnings to save many lives.

Sediment is changed to sedimentary rock by:

Cementation by hard-water deposits, intergrowth of new minerals, and squeezing under the weight of additional sediment.

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.

Many of the headstones in graveyards are made of granite. What are these granite headstones turning into?

Clays, rust, and sand that go into making soil beneath them, and ions that wash away.

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:

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.

Which of the following is NOT a job that geology graduates commonly get hired for:

Cloning new biological organisms for use in international terrorism.

Among fossil fuels:

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

A glacier flowing down the side of a mountain has come into balance with the climate. Then, a climate change occurs, so that melting exceeds snowfall on the glacier. The glacier will:

Continue flowing down the mountain, but shrink until a new balance is reached or until the ice disappears (of course, it must quit flowing as it disappears!).

Which is the second-oldest sedimentary rock layer?

D 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, and D is second-oldest.

Heat transfer by radiation is:

Efficient through space but inefficient through rocks.

Glaciers move by:

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

Two neutral atoms have the same number of protons in the nucleus, but different numbers of neutrons. These are:

Different isotopes of the same element.

In the picture above, the ice that modified the rock moved:

From left to right, striating the surfaces the ice reached first and plucking blocks loose from the far sides of bumps.

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.

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.

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 the scraped-off material is added to their edges at subduction zones.

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).

What is accurate about the history of extinction of species:

Extinction happens at a slow, "background" rate, punctuated by rare "mass extinctions" during which many types are eliminated rapidly.

Religion and science always disagree.

False

Which is younger:

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.

If humans change the composition of the atmosphere in a way that would warm the world by one degree if everything else in the Earth system remained unchanged, most studies indicate that over the next years to decades:

Feedback processes will enhance this warming a little, causing the total warming to be a few degrees.

A glacier almost always flows:

From where the glacier's upper surface is high to where the glacier's upper surface is low.

As rain falls through air, the water typically:

Gains carbon dioxide (CO2) from the air, becoming a weak acid

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.

The above image is a satellite picture of Cape Cod. What is most accurate about the past and future of the Cape?

Glaciers built a pile of sand and gravel where rivers cannot sustain it, and the Cape eventually will disappear beneath the waves.

In affecting the landscape:

Glaciers that are frozen to their beds don't do much, but glaciers that are thawed at their beds and have a lot of meltwater change things rapidly.

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.

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 silica found in the layer.

The interactions at the edges of plates are very important. Which is NOT an interaction that is commonly observed all along the length of one of the edges where two plates meet?

Hot spot.

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.

Examine the two pictures above, labeled I and II. They are from the same sediment core collected in sea-floor muds from beneath the Atlantic Ocean off the coast of South Carolina. (The pictures are scanning electron micrographs by Brian Huber of the Smithsonian Institution, and the scale is the same on both, as shown at the bottom of each.) One picture shows a sample from just below the unique layer marking the extinction that killed the dinosaurs, and the other picture shows a sample from just above that unique layer. Which is which?

I is from below the unique layer, and II is from above the unique 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?

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

During the most recent ice age:

Ice from Canada advanced across the Great Lakes and into the northern states of the US, but not farther.

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

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

What is an important idea that geologists use to put sedimentary rocks in order from older to younger?

In a normal pile of sedimentary layers, the layer on the bottom is the oldest, and the layer on the top is the youngest.

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

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

The Cenozoic:

Is "new life", the age of mammals.

The Paleozoic:

Is "old life", the age of shellfish.

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.

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.

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:

Land is sinking in some places as it recovers from being bulged up beyond the edge of the ice-age ice sheets.

A grand piano in a house in one of the lowest-elevation regions of New Orleans protected by the human-made levees is:

Lower in elevation than a kayaker on the river when the river is carrying its average water flow.

Silica tends to polymerize in lavas and make them thick and lumpy. Ways to reduce polymerization of silica in lava include:

Making the lava very rich in water and carbon dioxide.

What sort of rock is pictured above? (black and white stripes with swirly in the middle)

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 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:

More species in the larger park, because it can hold more individuals thus reducing the risk of extinction.

During chemical weathering, sodium is released as dissolved ions and transported to the ocean, where:

Most of it stays in the water for a while, making the water salty.

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.

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.

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, explosively erupting stratovolcano, and Hawaii has low-silica, quietly erupting shield volcanoes.

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?

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.

Soil is produced by weathering of rocks, and moved to streams by mass-movement. Our understanding of nature and humans shows:

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.

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.

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.

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.

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

Peat, lignite, bituminous, anthracite.

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.

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.

The geologic time scale is, starting with the oldest and ending with the youngest:

Precambrian, Paleozoic, Mesozoic, Cenozoic.

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.

In age dating, geologists use:

Radiometric techniques and layer-counting for absolute dating of events that happened in the last 100,000 years, and other radiometric techniques for absolute dating of much older events.

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.

Geologically speaking, the water table:

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

What happened in the picture above?

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.

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

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.

You drill through the muds at the bottom of the sea floor and sample the rocks beneath, and you then determine the ages of those rocks, using standard scientific techniques. As described in the course materials, you will find that:

Rocks farthest from spreading ridges are oldest, with ages decreasing as you move toward a ridge.

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.

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.

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?

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.

What is accurate about the land surface today, that you can observe in places such as Pennsylvania?

Sediment is being deposited in a few places, but most places are eroding.

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:

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

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.

Sandy beaches:

Shrink if the sand supply from rivers or coastal erosion is smaller than the sand loss to deep water, and grow if sand supply exceeds the sand loss, remaining in balance if sand supply equals sand loss.

What tectonic setting is primarily responsible for producing the great San Francisco earthquake and the San Andreas Fault?

Slide Past

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)?

Slide-past (or transform, with horizontal but no vertical movement) earthquakes and faults such as the San Andreas.

There are many large mammals on Earth today. This is because:

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.

The cartoon above illustrates a specific geologic process. Which of the additional geologic images DOES NOT feature this same process at work? (Dr Seuss cartoon)

Snowy Mountain Range 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. Death Valley records different processes.

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:

Soil creep, slow motion of pieces from freeze-thaw action, throw by falling roots, downhill motion of rocks during digging of gopher holes, etc.

In the Great Smokies:

Some older rocks were shoved on top of younger ones by push-together thrust faulting.

Before they can be published, scientific papers must be peer-reviewed. This means that:

Some other scientific experts read the papers and provide quality control by eliminating many mistakes.

The stiff basaltic rocks of the sea floor are bent as they enter subduction zones. This means that:

Subduction zones produce sea-floor trenches, which may be filled with water or with sediment washed from nearby land.

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.

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.

What is more accurate about the Earth?

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 top picture from the coast of Greenland, and the bottom picture from Bear Meadows Natural Area in central Pennsylvania, are geologically related. How?

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.

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?

The action of mass wasting, as soil and rock collapses off of newly steep canyon walls initially carved out by water.

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:

The article in the Journal of the American Medical Society, a peer-reviewed scientific journal, reporting on the discovery and testing of the drug.

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

The canyon is wider at the top and narrower at the bottom because the river was wider when the region was wetter, and has narrowed as deserts spread recently.

We now know a lot about the big processes that shape the Earth's geology. Which of the following is NOT correct about that knowledge?

The deeper layer, the lithosphere, floats beneath the upper, denser asthenosphere, with convection in the upper layer.

Melting happens in association with a subduction zone. What is going on to cause this?

The downgoing slab takes along water, and that water lowers the temperature at which rock melts to allow melting in and near the slab.

The picture above illustrates what scientific principle? (Dr Alley with North Pole on his head, the Equator on his cheek, and his computer screen lit up)

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 illustrates what scientific principle? (Dr. Alley north pole, equator, and sun)

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

Large rivers have many interesting features, including:

The flood plain, the nearly flat region farther from the river than the natural levees and composed of mud deposited by the river's floods.

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 less by a magnitude-4 quake than by a magnitude-5 quake.

Air that passes over the Sierra Nevada from the Redwoods to Death Valley is warmed by roughly 30oF, even if the air goes over at night. Where does the energy come from?

The heat that had been stored during evaporation from the ocean and was released when clouds formed on the west side of the Sierra

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.

Often, landowners along eroding beaches will build groins, which are walls or dams sticking out into the ocean or lake from the beach. Why are these built, and what happens?

The landowners are trying to catch sediment from the longshore drift to add to the beach; this can work, but often erosion on the "downstream" side of the groin makes the neighbors mad.

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.

Which is accurate about the Earth?

The lithosphere usually breaks rather than flows, and the asthenosphere usually flows rather than breaks.

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.

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.

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?

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.

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.

Stephanie and Topher are standing next to the Colorado River in the Grand Canyon. What can be said of the water here?

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.

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?

The rock was carried here by glacier ice and left when the ice melted.

For this question, ignore sand and gravel moved by rivers and wind and such surface processes, and think about the big motions that have affected Death Valley. What are they?

The rocks under the valley floor have been moving down relative to similar rocks in nearby mountains, and at the same time the mountains east and west of the valley have been moving apart, away from the center of the valley.

Pieces of bedrock from Canada are spread across large areas of northwestern Pennsylvania, even though the Great Lakes are between Pennsylvania and Canada. How do geologists explain this?

The rocks were carried into Pennsylvania by a glacier flowing from Canada; the base of the ice was able to flow uphill from Lake Ontario into Pennsylvania because the top of the ice sloped down toward Pennsylvania.

Suppose you wrote a big check to someone to go out into deep water and haul sand up to replenish your private beach along the Atlantic coast. What is this most likely to cause?

The sand will be moved back into deeper water by waves and currents over the next year or years.

You use highly accurate techniques to learn the time when lots and lots of different volcanic rocks solidified from melted rock. You do this for many different rocks across the continents, and many different rocks across the sea floor. You will find that (note that "older" rocks are those that solidified more years ago, and "younger" rocks are those that solidified fewer years ago.):

The sea-floor rocks are typically younger than the continental rocks, because sea-floor rocks are taken back into the mantle at subduction zones about as rapidly as new sea-floor rocks are produced, while continental rocks are not taken back into the mantle at subduction zones.

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.

Geologists got their shorts tied in knots because they (the geologists, not the shorts or the knots) were so excited when they discovered what about the pattern of sediment thickness across undersea spreading ridges:

The sediment is thin near the ridges, and thickens as you go away from the ridges, because the rocks near the ridges are young and have had little time to accumulate sediment, whereas rocks farther away are older and have had longer to accumulate sediment.

One practical radioactive system used to date lava flows involves:

The solid potassium-40, which decays to the gas argon-40.

The concentration of CO2 in the atmosphere rose as the last ice age ended, and then stabilized for thousands of years, until humans became serious about changing the atmosphere with the start of the industrial revolution. Suppose that we succeed in raising the CO2 concentration in the atmosphere to a level twice as high as occurred for the thousands of years after the ice age and before the industrial revolution, and then we hold the concentration constant at that new, higher level for the next thousand years. What would happen to the average temperature of the planet?

The temperature would increase to a few degrees above the pre-industrial-revolution level, and then stabilize at that new, warmer level.

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.

The cartoon above illustrates a specific geologic process. Which of the additional geologic images DOES NOT feature this same process at work?

first picture (mountain island)

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:

The various diseases that come from smoking, overeating and under-exercising for a long time.

People visit Death Valley for all sorts of reasons. Some people even go there to study volcanoes. What is accurate about those Death Valley volcanoes?

The volcanoes near the edges of Death Valley produce rocks that are similar in composition to the rocks made by volcanoes at undersea spreading ridges, because Death Valley is in many ways geologically linked to undersea spreading ridges.

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.

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?

They occur at subduction zones, where the rising pressure on rock as it is taken deeper seems to cause "implosion" of minerals as they rearrange to take up less space.

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 is known scientifically about transitional forms in the fossil record?

They are found frequently for those general types of living things (such as shelly shallow-marine creatures) that commonly produce fossils, but are not found as frequently for other general types.

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.

The ptarmigan and the marmot have something in common, other than being cute. What is it?

They both are standing on glacially eroded surfaces.

Look at the picture above of a small dam across a stream bed (between the pink arrows) just above one of the trails into Bryce Canyon. When floods happen in the stream bed:

They flow toward the camera; floodwaters have filled the space upstream of the dam and debris has started to cascade over the dam, so the dam is not serving to trap sediment any more.

One of the big problems faced by National Parks is that:

They must allow people to enjoy things today, and preserve those things for the future, but achieving both of these is not easy.

The things that glaciers deposit include:

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

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.

John Wesley Powell, who led the first boat trip through the Grand Canyon, called the feature marked by the yellow lines "The Great _________". What did he put in the blank?

Unconformity.

The picture above shows a muddy sandstone that was deposited on a flood plain. Dr. Alley's index finger in the lower left points along a ridge on the surface of the rock (shadows are to the lower right of Dr. Alley's finger and to the lower right of the feature he is pointing along; his finger is above the rock, so the feature must be a ridge and not a trough). The rock is:

Upside-down; you are looking at the side that was facing down toward the center of the Earth when the rock was deposited.

The "Law" of Faunal Succession:

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

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.

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.

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.

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)?

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 dam is built on a river that has a river bed that is primarily sand. You have a house just downstream of the dam, and you like to go trout fishing in the river in front of your house. A few years after the dam is built, it is likely that:

You will have built a ladder or steep path to get down to the river, because the clean water released by the dam will have washed a lot of the sand away and lowered the elevation of the river in front of your house.

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 your head on that surface (assuming you are a typical-sized human being), what would be true? (In an average year, Pennsylvania gets about the same amount of precipitation as the average for the world.)

You would be breathing by SCUBA or snorkel, because the water would be up between your belly button and your knees somewhere.

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:

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.

Which is younger:

the tree

The pink arrows point to a barrier beach, formed when waves fromthe ocean (on the left) washed away mud and piled up sand, after themud and sand were delivered by the stream flowing in from the upperright. The yellow arrows point to interesting features. How did they form?

A storm broke through the barrier beach and pushed sand farther inland.

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.

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.

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.

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:

Buy the corridor connecting the two parks; this keeps one big "island" rather than two smaller ones, and so keeps more species.

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:

Global sea level is rising, covering more land.

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 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.

What is accurate about sediments and sedimentary rocks and metamorphic rocks?

Squeezing and heating can turn loose sediment into sedimentary rock, and sedimentary rock into metamorphic rock, with all the intermediate steps observed in nature.

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.

In the photo above, Dave Janesko is explaining the great Sevier Fault to Dr. Alley and the CAUSE class. On the left, red rocks deposited in a lake extend off to Bryce National Park. On the right, black lava flows, now cooled and hardened, are visible. The rocks meet at the Sevier Fault. What happened here?

The fault formed during Death-Valley-type spreading in the west, with the younger, black lava flows dropping along the fault to lie next to the older, red 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.

Dave Janesko is explaining the great Sevier Fault to Dr. Alley and the CAUSE class. 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.

20-mule teams hauled borax salts out of Death Valley, and the valley still has lots of salt, sand, and river gravel in the bottom. The most likely explanation is:

The valley was dropped relative to the mountains by faulting, and rivers have been (and still are) carrying gravel, sand and salts down from the mountains into the valley; then the water evaporates and leaves the gravel, sand and salts behind.

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.