Lesson 28: Chapter 28 Geologic Time

Which of the following best describes the relative age of Rocks A and C compared to Rock B (oldest to youngest)? A. A and C, B B. B, A and C

A and C, B

Which of the following best describes the relative age of A and C (oldest to youngest) A. A is oldest B. C is oldest

A is oldest

Which principle of relative dating was used to provide the correct relative dates of these rocks? A. Original horizontality B. Superposition C. Cross-cutting D. Inclusions E. Faunal succession

Cross-cutting

A layer of rock contains the two fossils shown below: What interval(s) of time, as indicated by the numbers 1-8 at the right of the diagram, is represented by the simultaneous existence of these two animals?

I HONESTLY HAVE NO IDEA

Which principle of relative dating was used to provide the correct relative dates of these sedimentary layers? A. Original horizontality B. Superposition C. Cross-cutting D. Inclusions E. Faunal succession

Superposition

The picture above shows three different types of rocks, A, B, and C. Which principle of relative dating can be used to provide the relative dates of rocks A and C? A. Original horizontality B. Superposition C. Cross-cutting D. Inclusions E. Faunal succession

inclusions

Could the sedimentary rock be successfully dated by radiometric means?

no

Of the two craters marked in the orange square in the lower right corner, which is the youngest? A. the upper left crater B. the lower right crater

the lower right crater

What are the relative dating principles?

- original horizontality - superposition - cross cutting - inclusions - faunal succession

Inclusions

- rock that is included (surrounded by) other rock must be older than the surrounding rock - solid materials enclosed within another solid are older than the rock that encloses it

Cross-Cutting

- rocks are older than the features or rocks that cross cut them - rock that is cut is older than the other rock, fault, crack, that did the cutting

Original Horizontality

- sedimentary rocks are deposited in horizontal layers - any tilting, folding, or deformations occurred after initial deposition

Superposition

- the oldest layer will be on top of the bottom and the youngest on top - the rocks on bottom are older than the rocks on top

Faunal Succession

- within stacks of sedimentary rocks, there is a pattern of change in the types of fossils the layers contain - the fossils can therefore help us determine the relative age of different layers - fossil assemblages (groups) found in sedimentary rocks are diagnostic of rock age - extinct assemblages never appear in younger rocks

Which of the following best describes the relative ages of the rocks (oldest to youngest)? A. A, B, C B. B, C, A C. C, A, B D. A, C, B E. B, A, C F. C, B, A

A, C, B

Now compare the craters marked A with the crater whose wall is marked by B. Which is older, A or B? A. A B. B

B

alt="Picture shows rock layer A being cut through by rock B."/> The picture above shows two different rock types, A and B. From the choices below, select the sequence from youngest to oldest. A. A, B B. B, A

B, A

Refer to the figure above. Which of the following lists has the rocks ordered from oldest to youngest? (E is a fault, not a rock) A. A, B, C, D B. B, A, C, D C. B, A, D, C D. A and B (you can't tell which), then C and D (you can't tell which)

B, A, D, C

In the picture for the question above, what is the correct order of layers from oldest to youngest? A. A, B, C, D, E B. B, A, C, D, E C. B, C, A, D, E D. B, C, D, A, E E. B, C, D, but then you can't tell whether A or E is older

B, C, D, but then you can't tell whether A or E is older

Compare the rays of ejected material marked D (from a crater just off of the bottom of the picture) with the lava plain marked C. Which is older, C or D? A. C B. D

C

The following picture shows features on our moon. Compare the craters marked A with the lava plain marked C. Which is older, A or C? A. A B. C

C

Which of the following is the oldest feature marked in the photograph?

C

The picture above shows some layered sedimentary rocks. Which of the following best describes the age of the rock layers (oldest to youngest)? A. A, B, C B. B, C, A C. C, A, B D. A, C, B E. B, A, C F. C, B, A

C, B, A

Where are the youngest visible beds of sandstone located in this photograph? A. at the top B. at the bottom

at the top

Which principle of relative dating can be used to provide the relative dates of Rocks A and C versus Rock B? A. Original horizontality B. Superposition C. Cross-cutting D. Inclusions E. Faunal succession

cross-cutting

Which principle of relative dating did you use to obtain your answer? A. Original horizontality B. Superposition C. Cross-cutting D. Inclusions E. Faunal succession

cross-cutting

Which principle of relative dating did you use? A. Original horizontality B. Superposition C. Cross-cutting D. Inclusions E. Faunal succession

cross-cutting

Could either the sandstone or the igneous rock be candidates for the oldest rock on the earth? A. Yes, the sandstone could because it is older than the igneous rock. B. Yes, the igneous rock could because it is older than the sandstone. C. No, the sandstone consists of fragments eroded from rocks that are older than it is, and the igneous rock is younger than the sandstone. D. No, the first rocks would have to have been metamorphic rocks.

no, the sandstone consists of fragments eroded from rocks that are older than it is, and the igneous rock is younger than the sandstone

If the igneous rock is dated to be 34 million years old, what principle of relative dating was used to get this result? A. None, that's an absolute date. B. Original horizontality C. Superposition D. Cross-cutting E. Inclusions F. Faunal succession

none, that's an absolute date

In this picture, A and C are igneous and are 33 and 21 million years respectively. B is sedimentary rock. What is the age of this sedimentary layer? A. Younger than 21 million years B. Between 21 and 33 million years C. Older than 33 million years

older than 33 million years

Which principle of relative dating did you use to obtain your answer? A. Original horizontality B. Superposition C. Cross-cutting D. Inclusions E. Faunal succession

superposition

Which principle of relative dating did you use? A. Original horizontality B. Superposition C. Cross-cutting D. Inclusions E. Faunal succession

superposition

When you date a rock using radiometric dating, what does the number actually mean? A. The age of the radioactive atoms used in the dating process. B. The age of the daughter molecules produced by radioactive decay. C. The age of the elements that make up the molecules from which the rock is composed. D. The date when the volcano that produced the rock erupted. E. The date when the minerals within the rock cooled and solidified.

the date when the minerals within the rock cooled and solidified

If the igneous rock is dated to be 34 million years old, what happened 34 million years ago? A. The volcano that produced the intrusion erupted. B. The fault that the lava traveled through formed. C. The minerals that make up the igneous rock formed. D. The lava solidified. E. The sandstone started to form around the lava.

the lava solidified

Suppose you have a rock sample containing uranium, some of which is 235U, which decays to 207Pb with a half life of 713 million years. You find that only 25% of the original 235U is still present, the rest having decayed to 207Pb. What can you determine about the age of the rock? A. The rock is less than 713 million years old. B. The rock is 713 million years old. C. The rock is 1.4 billion years old. D. The rock is 2.1 billion years old. E. The age of the rock cannot be determined.

the rock is 1.4 billion years old

In the picture above, A is a rock radiometrically dated at 37 million years. What can you conclude? A. Using cross-cutting relationships, we know that B is older than 37 million years. B. Using superposition, we know that B is older than 37 million years. C. Using superposition, we know that B is 37 million years old. D. Using inclusions, we know that B is younger than 37 million years. E. Using faunal succession, we know that B is older than 37 million years.

using cross-cutting relationships, we know that B is older than 37 million years

Referring to the photograph by question 1 above, Rocks A and B represent rocks of any kind. Which of the following statements is true? A. We know Rock A is older by superposition. B. We know Rock B is older by superposition. C. We know Rock B is younger by cross cutting. D. We know that Rock A is older because it is an inclusion. E. We know that Rock B is older by inclusions. F. Not enough of Rock A and B are shown to determine the age.

we know rock B is younger by cross cutting

Referring to the photograph above, Rocks A and C represent rocks of any kind. Which of the following statements is true? A. We know Rock A is older by superposition. B. We know Rock C is older by superposition.term-6 C. We know Rock C is older by cross cutting. D. We know that Rock A is older because it is an inclusion. E. We know that Rock C is older by inclusions. F. Not enough of Rock A and C are shown to determine the age.

we know that rock A is older because it is an inclusion

Could the igneous rock be successfully dated by radiometric means?

yes

Consider the features shown in the photograph above.The gray igneous rock is (younger, older) than the red sandstone.

younger