Homework # 4 Relative Dating Section:

Name: Date:

1. The cross section below represents a portion ofEarth’s crust. Letters A through D are locationswithin the rock units.

At which location is quartzite most likelyfound?

A. A B. B C. C D. D

2. Base your answer(s) to the following question(s)on the geologic cross section below, whichshows rock units 1 through 7 that have not beenoverturned. Some of the rock units containNew York State index fossils. An unconformityexists between rock units 5 and 6.

Key

Basalt

Volcanic ash

Contact metamorphism

What evidence shown in the cross sectionindicates that the basalt rock unit is theyoungest rock unit?

3. Bedrock from which entire geologic time periodis missing between rock units 5 and 6?

4. Identify one metamorphic rock that could havebeen formed by the contact metamorphismwithin rock unit 1.

5. The sequence of rock types found in the wallsof the Grand Canyon are shown. The namesof rock formations are shown and the upperand lower boundaries of each formation areindicated by dashed lines. The rock layers havenot been overturned.

The sequence of rock layers in the cross sectionprovides evidence that the Muave formation is

A. younger than the Temple Butte, but olderthan the Bright Angel

B. younger than both the Temple Butte andthe Bright Angel

C. older than the Temple Butte, but youngerthan the Bright Angel

D. older than both the Temple Butte and theBright Angel

6. The geologic cross section below shows bedrocklayers A through D. Line XY is a fault.

The fault most likely occurred after

A. all bedrock layers were formed

B. layer C formed, but before layer D formed

C. layer A formed, but before layer B formed

D. layer B formed, but before layer C formed

page 1

7. Base your answer(s) to the following question(s)on the cross section below. Rock units arelabeled 1 through 8. The line between A andA’ indicates an unconformity.

Which event occurred sometime after theformation of the unconformity?

A. formation of rock unit 3

B. tilting of rock unit 5

C. deposition of the sediments that formedrock unit 8

D. intrusion of rock unit 7

8. Which characteristic of the granite intrusionprovides the most evidence that it solidifieddeep underground?

A. very hard B. coarse texture

C. light color D. felsic composition

9. Earth has sedimentary bedrock of marine originthat is four billion years old. Which inferencecan be made from this information?

A. Earth had oceans four billion years ago.

B. Sedimentary rocks formed from magmawhen Earth cooled four billion years ago.

C. Most sedimentary rocks are at least fourbillion years old.

D. Life existed on Earth four billion yearsago.

10. The cross section of the bedrock layers of acanyon is represented below. Letters A and Brepresent rock layers on the sides of the canyon.

Layer A can best be correlated to layer B bycomparing the

A. sediments on each side of the stream

B. sequence of rock layers on each side of thecanyon

C. organisms currently living in rock layers Aand B

D. rate of erosion of rock layers A and B bythe stream

11. Base your answer(s) to the following question(s)on the block diagram below, which showsbedrock units A through F and boundary XX′.

The rock that formed in the contactmetamorphic zone between rock unit E androck unit D is

A. hornfels B. marble

C. schist D. anthracite coal

Section: page 2 Homework # 4 Relative Dating

12. Base your answer(s) to the following question(s)on the geologic cross section of bedrock shownbelow. A through G identify rock layers and Qrepresents a fault. Lines W, X, Y, and Z arelocations of unconformities. The rocks have notbeen overturned.

Which rock or feature is oldest?

A. rock A B. rock G

C. fault Q D. unconformity Z

13. The movement of bedrock along fault Q mostprobably produced

A. gaps in the rock record

B. an earthquake

C. a volcanic lava flow

D. zones of contact metamorphism

14. The unconformities shown in the cross sectionrepresent

A. buried erosional surfaces

B. locations of index fossils

C. volcanic ash deposits

D. boundaries between oceanic and continentalcrust

15. Identify two processes that produced theunconformity.

16. Base your answer(s) to the following question(s)on the geologic cross section below. Location Ais within the metamorphic rock.

Which rock is the youngest?

A. shale B. sandstone

C. igneous rock D. rock at location A

17. Base your answer(s) to the following question(s)on the cross section below and on yourknowledge of Earth science. The cross sectionrepresents rock units that have not beenoverturned. Lines CC′ and GG′ representunconformities. The geologic ages of some ofthe lettered rock units are shown below thecross section.

The diagrams below represent three indexfossils found in one of the rock units.

These fossils are most likely found in

A. rock unit I B. rock unit J

C. rock unit K D. rock unit M

Section: page 3 Homework # 4 Relative Dating

18. Base your answer(s) to the following question(s)on the geologic cross section below in whichoverturning has not occurred. Letters Athrough H represent rock layers.

Which two letters represent bedrock of thesame age?

A. A and E B. B and D

C. F and G D. D and H

19. The diagram below represents three bedrockoutcrops. The layers have not been overturned.Letters A through E identify different rocklayers. Fossils found in the rock layers areshown.

Which fossil could be classified as an indexfossil?

A. B. C. D.

20. Which scientific principle states that youngerrock layers are generally deposited on top ofolder rock layers?

a. superposition b. evolution

c. original horizontality d. includsion

21. The cross section below represents fourdifferent rock units. The symbol for contactmetamorphism has been omitted from the crosssection.

The sequence below represents the relative agesof the rock units from oldest to youngest.

limestone → granite → shale → sandstone

Which cross section below represents where thesymbol for contact metamorphism would belocated, based on the relative age sequence?

A.

B.

C.

D.

Section: page 4 Homework # 4 Relative Dating

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Section: Homework # 4 Relative Dating 09/28/2016

1.Answer: C

2.Answer: Basalt cuts across all other rock units. /

Contact metamorphism is shown betweenthe basalt and all rock layers.

3.Answer: Ordovician Period.

4.Answer: marble or hornfels

5.Answer: C

6.Answer: D

7.Answer: A

8.Answer: B

9.Answer: A

10.Answer: B

11.Answer: A

12.Answer: B

13.Answer: B

14.Answer: A

15.Answer:

16.Answer: A

17.Answer: C

18.Answer: D

19.Answer: C

20.Answer: a.

21.Answer: A