rockon 10

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

C,D,E,F,B

Which is older:

Unconformity L

Which is younger:

the tree

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

150

You start with 800 parent atoms of a particular radioactive type, which decays to give stable offspring. You wait just long enough for two half lives to pass. You should expect to have how many parent atoms remaining (on average):

200

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 none of those stable offspring. You wait just long enough for two half lives to pass. You should expect to have how many offspring atoms (on average)(remember that the number of parents and the number of offspring add up to 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

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

Which is accurate about the Grand Canyon, in Arizona:

A great thickness of sedimentary rocks exists in Death-Valley-type faulted basins, which can be seen deep in the canyon in many places.

Two yellow lines have been drawn on the picture by the instructional team. These lines follow an interesting surface, which separate flat-lying sedimentary rocks, on top, from slanting sedimentary rocks beneath. This surface is:

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

What is indicated by the yellow lines in the image above, which separate flat-lying sedimentary rocks, on top, from slanting sedimentary rocks beneath?

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

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

A little over 1 yard

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.

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

B F E D C

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

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 is the youngest fault:

H

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

I,J,H

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.

Early geologists did not have radiometric dating techniques, or long layer-counted histories. Instead, they followed William Smith 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.

Using only uniformitarian calculations from the thickness of known sedimentary rocks, likely rates at which those rocks accumulated, and features in and under those sedimentary rocks, geologists working two to three hundred years ago estimated that the Earth:

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

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

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

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 far on the football field would represent the time between the first appearance of abundant shelly creatures and today?

Just over 10 yards.

What is accurate about the scientific results learned by counting annual layers in ice cores?

Many tests show that some ice cores have reliably preserved annual layers, and the longest record extends back more than 100,000 years.

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.

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.

The above photograph was taken in the Grand Canyon, and shows a cliff that is approximately 30 feet high. What are the rocks in the cliff?

Precambrian metamorphic rocks with some igneous rocks intruded; the folding was caused by mountain-building processes when the rocks were very hot deep in a mountain range.

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.

The two pictures above, I and II, show fossils inrocks from the Grand Canyon. Each is "typical"; the rocks near sample Icontain fossils similar to those shown in sample I, and the rocks nearsample II contain fossils similar to those shown in sample II. It is likely that:

Sample I is from high in the cliffs of the Grand Canyon, and sample II is from much lower, near the river.

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.

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.

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

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

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

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.

One practical radioactive system used to date lava flows involves:

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

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 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)?

Uniformitarian calculations show that the Earth is more than about 100 million years old, and radiometric techniques tell us how much older.

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.

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

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