Earth Science: Geology, the Environment, and the Universe

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Fossils can help to match rocks of the same age, even when you find those rocks a long way apart. We will visit it again but only virtually! Correlation can involve matching an undated rock with a dated one at another location.

If the block has units with letters on them, put the letters in order from oldest to youngest, like we did with the two examples above. There can be lots of complexities,such as folding events, faulting, erosion events, intrusion by magma, etc. South Half -- North Half -- Question 5: On the South Half, approximately how high is Hopi Point on the Coconino Plateau?

Relative Dating Exercises - The previous layers are eroded off at the top too. Between which two rock formations use the letter labels did this tilting occur?

Examine the geologic cross sections which follow, and determine the relative ages of the rock bodies, lettered features such as faults or surfaces of erosion, and other events such as tilting, folding, or erosion events. Always start with the oldest rock and work toward the present. List the letters in order, with the oldest at the bottom. For each of the relative dating diagrams, you are to think about them like the side view of a layer cake. In general, the oldest units are on the bottom and the youngest units are on the top. There can be lots of complexities,such as folding events, faulting, erosion events, intrusion by magma, etc. You have to put these events into the order in which they occurred, starting with the oldest, and working toward the youngest. If a fault cuts a bed, then the bed is older than the fault. For Block A above, the sedimentary units are in sequence, P, K, M, and S. So it comes next in the sequence. The intrusion is eroded off at the top. The previous layers are eroded off at the top too. So the event The diagrams below are similar to the examples above. If the block has units with letters on them, put the letters in order from oldest to youngest, like we did with the two examples above. Add words for erosion events, folding events, intrusions, faults, tilting, etc. X's, V's, o's, dashes, black unit, white unit, bricks, dots, etc. You can also look at the lithologic unit symbols on the blocks and use the words for the rock type in place of the description of the symbol. V's are volcanic rock, X's are plutonic rocks, etc. Just put your words in order from oldest to youngest, like you did with the other diagrams.

Relative Dating Re teach
We could draw such a profile across several miles of landscape so we would see a side-view of the land's surface over which we might be hiking. For example, a xenolith in an igneous rock or a clast in sedimentary rock must be older than the rock that includes it Figure 8. The pieces of shale were eroded as the sandstone was deposited, so the shale is older than the sandstone. Different species of ammonites lived at different times within the Mesozoic, so identifying a fossil species can help narrow down when a rock was formed. Add words for erosion events, folding events, intrusions, faults, tilting, etc. Each rock layer was deposited at a different geologic time. What principle s of relative dating did you use in order to arrive at your interpretation of the relative timing of each event?