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. Referring to the rocks you see here ...... 1. Which is the oldest sedimentary rock layer: A. F B. B C. C D. D E. E 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. Points Earned: 1/1 Correct Answer: C Your Response: C
2. Which correctly gives the order of the faults, from youngest (first) to oldest (last):
A. H, I, J B. I, H, J
C. I, J, H D. J, H, I E. 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. Points Earned: 0/1 Correct Answer: E Your Response: C
3. Which is older:
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 I is the oldest on this list. Points Earned: 1/1 Correct Answer: C Your Response: C
4. Which is younger:
The tree is growing on intrusion G, which can be shown to be younger than all of the others. Points Earned: 1/1 Correct Answer: C Your Response: C
5. Which is not accurate about the Grand Canyon, in Arizona:
The rock record of the canyon contains many unconformities. There are some folded rocks in the heart-of-a-mountain-range metamorphics at the bottom,
but otherwise, everything is right-side up. All the other possible answers here are correct.

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- Summer '14
- rocks, Correct Answer