Geoscience 10 Final

During the most recent ice age:

Central Pennsylvania was just beyond the edge of the Canadian ice

What is an important idea the 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

Which is accurate about the history of the Grand Canyon:

In the deepest part of the canyon, the river cuts through rocks formed by metamorphism of older sedimentary rocks in the heart of a mountain range

And what above this one (above)? What do the yellow lines mark?

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

One way to treat a dying beach is to dig up sand somewhere and dump it on the beach. What is this likely to accomplish?

It causes the beach to lose the new sand over the new year or years, as the extra sand is washed back to deep water by waves and currents

Evidence that glaciers were much bigger about 20,000 years ago than they are now includes:

20,000-year-old deceased shallow-water corals occur in growth position far below the surface on the sides of oceanic islands

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 in a single step to give a stable offspring, and you start with non of those stable offspring. You wait just long enough for two half lives to pass. You should expect to have how many offspring atoms (on average)(remember that the number of parents and the number of offspring add up to 400, so if you have 10 parents, you have 390 offspring because 10 and 390 add up to 400. and if you have 20 parents you have 380 offspring and so on)

300

The Petrified Forest of Arizona includes a great diversity of fossils. In the picture above, paleontologist Randall Irmis excavates a late 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

Scientific evidence indicates that the Earth is about how old?

4.6 billion years

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

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 gavel, 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

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.

What can you learn about past environments fro 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

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

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

There are many greenhouse gases, including carbon dioxide (CO2), methane (CH4), and vaporized water (H20). These and other greenhouse gases warm the Earth primarily by:

Absorbing some of the infrared radiation emitted from the Earth

How about this one (above)? What is it?

Algal-mat deposits in Precambrian rocks of the Grand Canyon

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

A widely accepted scientific idea usually is based on:

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

When geologists consider sedimentary rocks, those rocks:

Are classified first based on origin (clastic or chemical precipitate)

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

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

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

At regular and repeating times, controlled by redistribution of sunlight on the surface of the Earth in response to features of Earth's orbit, even though total sunshine received by the planet didn't change much

In a glacier, the ice moves fastest:

At the upper surface, where ice meets air

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

The above picture shows ocean int he upper right, a beach, and land (lower left). The red dashes trace the crest o a wave. Waves move perpendicular to their crests. What principle is illustrated by the pictures?

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.

If you were looking for different types of coal, you likely would find:

Bituminous in the sedimentary rocks of western Pennsylvania, and anthracite in the metamorphic rocks of eastern Pennsylvania

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 fast enough rate to matter to our economy, the resource will run out because use is much faster than natural production. What do we know bout 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

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

Cenozoic, Mesozoic, Paleozoic, Precambrian

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

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

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 layered 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

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

C, D, E, F, B

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

CO2 + H20 + energy - CH20 + O2

One way that sediment is changed to sedimentary rock is by:

Cementation, a process that occurs in nature, and that is similar to processes that can occur in plumbing and other things humans make.

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, potentially 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

Among fossil fuels:

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

What cause probably was not important in contributing to extinction of most species on Earth, including the dinosaurs, in a very short interval of time at the end of the Mesozoic Era?

Cold from the change in earth's orbit caused when the meteorite shoved the planet farther from the sun

Considering long-term averages, and assuming that we don't deploy space-based defenses against incoming meteorites, a reasonable estimate of the change 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

Look at the picture, which shows a small section of a "fossil" sand dune (a sand dude in which the grains have been "glued" together by hard-water deposits). When the dune was first deposited, which was done (which letter is closest to the arrow that is pointing in the direction you would have liked to see the ground when the dune was deposited?

D

When considering the land surface:

Deposition of sediments occurs in only a few places, with erosion of non deposition occurring in most places to produce unconformities, and one must piece together geologic history from rocks in many places

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)

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

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

Which is older?

Fault I

If humans could 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

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

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.

Again referring to the picture of the Cape above:

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

Sandy beaches:

Grow if sand supplied from rivers or from coastal erosion exceeds sand lost to deep water, and shrink if the sand supply is smaller than the sand loss

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

H, J, I

Which of the following is part of the evidence that the odd layer marking the extinction of the dinosaurs was caused by a large meteorite impact?

High concentration of iridium found in the layer

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 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 sedimentary 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

Which of the following is not 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

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

Early geologists did not have radiometric dating techniques, or long layer-counted histories. Instead, they followed William Sith in putting things in order, and then used uniformitarian calculations based on modern rates of processes and observed results of processes in the geologic record. These early geologists, using these techniques, found that the Earth:

Is more than about one-hundred million years old

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

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 shows a region a bit under 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 class. 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

You are told that a region has no glaciers. What does the lack of glaciers tell you about the climate of that region?

Melting removes all the snowfall

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 in 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

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

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

How is sediment related to sedimentary rock?

Sediment is gradually hardened to sedimentary rock by various processes, and the point where the name changes from sediment to seminary rock is somewhat arbitrary

And on the lighter side, look at the checkerboard arrangement of the little bushes in the lower part of that picture, on the near side and far side of the road. It is likely that:

Natural joints have formed, providing space for roots and for rainwater that the roots need

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 extinction when many types were killed over very short times

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 purpose. 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 jetty shown above was constructed along the coast of Washington. A likely interpretation of what you see here is:

Sediment transport is typically rom the right, casing deposition to the right of the hetty but erosion to the left

What is accurate about the scientific results learned by counting tree rings and other annual layer?

Records in the tree rings, lakes, and ice all reach beyond 12,000 years, and some of them reach beyond 40,000 years

Sometimes, people with scientific backgrounds say bad things about religion, and sometimes people with religious backgrounds say bad things about science. This is because:

Religion and science do not need to disagree, but sometimes science-background and religious-background people choose to disagree

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

Globally averaged, the level of the ocean is:

Rising, as warming causes the ocean to warm and expand, and as glaciers melt

And here's another (above). What do you suppose this is?

Rocks that were cooked, squeezed, and partially melted in the heart of an old mountain range, now found near the river in the Grand Canyon

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, casing deposition to the right of the jetty but erosion to the left

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

The picture above is of the coast of Acadia National Park. Look 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

What happened in the picture above?

Sediment eroded from the land has been transported along the shore and dammed the stream

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.

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

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

Glaciers form where:

Snowfall exceeds melting for a long enough time

Suppose that CO2 in the atmosphere was held at a constant, natural level for a few thousand year. 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 after the increase in CO2 was a few degrees higher than temperature before the increase

What is accurate about the "Law" of Faunal Succession?

The "Law" was developed from the observation that using geologic reasoning to put rocks in order from oldest to youngest also put the fossils in those rocks in order

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

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

The big W is in ocean water, while the little w is in water in a bay cut off from the ocean by the car 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 the erosion has been occurring as waves hammer this shore, and the bar shows that longshore transport is moving the sediment from the erosion along the shore.

The size of a typical sand 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

If you hike into Bryce Canyon, and ou 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 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) towards 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)

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 gavel. 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

Scientists say that glaciers flow. What does this mean?

The ice is almost warm enough to melt, and so the ice deforms slowly something like the rocks in the mantle or a chocolate bar in your pocket.

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.

The landsat age (above) from NASA shows Cape Cod. This is a pile of sand and gavel out in the north atlantic. The cape has no large rivers, and is not near any large rivers. Looking along the far right-hand side of the Cape, the white is sand of the great outer beach (magenta arrow) and the sand deposits are prominent to the north and south (yellow arrows). What might you infer from the picture?

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

The Landsat above image from NASA shows Cape Cod, Massachusetts. The short yellow arrow indicates sand deposits at Monomoy Island, a great place for bird-watching. The long pink arrows indicates underwater sand deposits. The dotted blue arrow points to the greater Outer Beach of the Cape. Based on material presented in this class, what is going on?

The outer beach (dotted blue) is losing sand to Monomoy (short yellow) which is losing sand to the undersea basis (long pink) which are losing sand to deeper water as the cape slowly shrinks.

During the most recent Ice Age, the great ice sheets produced many geologic features. Which of the following was NOT produced by the great ice sheets during that most recent ice age?

The piles of mud along the river crossing the Mississippi Delta

The picture above shows a very hard piece of rock about six inches across, in the Grand canyon. The surface of the rock looks rather different from the surface of many other rocks. What made this odd-looking surface?

The river, which blasted the rock with sand and silt laden water during floods; this shows that even hard rocks can be eroded by rivers

The picture above shows an outcrop along Interstate 70 in Utah. The green arrow points to a person, for scale. The pink arrows point to the ends of an interesting surface. Some rocks are below this surface, and other rocks above it. What happened to make this outcrop?

The rocks below were deposited hardened turned on end, eroded to make an unconformity with a soil developing on top, and then other rocks were deposited on top of the soil

Places 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.

You are hiking in the mountains and find some snow and ice. You drill a hole in the snow and ice to the bottom but not into the materials beneath. Later, you come back and measure the shape of the hole, and find that there has been no change. Based on the definition of a glacier, you should conclude:

The snow and ice you found are not a glacier, because glaciers must have deformation in the ice

One practical radioactive system used to data lava flows involves:

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

One practical radioactive system used to date lava flows involves:

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

What do you think is shown in the picture above?

The surface of rock scratched and polished by the river, along the Colorado in the Grand Canyon

Which is younger?

The tree

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.

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 last enough in comparison to sand supply that sandy beaches have not formed.

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

The things that glaciers deposit include:

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

Look back up at the jetty picture again - look specifically at the way the waves are behaving. A likely inference is that:

Waves go slower in shallower water

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 but the picture?

Waves go slower in shallower water

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

unconformity