Solved Correlating Rock Layers The two cross sections below ... - Free Printable

Problem Analysis

The task involves analyzing two cross-sections of rock layers in Arizona and Utah to determine their relative ages, identify fossil correlations, and reconstruct the geological history of the area. Let's solve each part step by step.

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Part a: Determine the history of each area and fill in the geologic columns

#### Arizona Cross-Section
1. Metamorphic Schist: This is the oldest layer, as it is at the bottom.
2. Sandstone: Deposited on top of the metamorphic schist.
3. Shale: Deposited on top of the sandstone.
4. Limestone: Deposited on top of the shale.
- The presence of fossils (indicated by symbols) suggests specific time periods for deposition.

#### Utah Cross-Section
1. Shale: This is the oldest layer, as it is at the bottom.
2. Limestone: Deposited on top of the shale.
3. Sandstone: Deposited on top of the limestone.
4. Shale: Deposited on top of the sandstone.
- The presence of fossils (indicated by symbols) suggests specific time periods for deposition.

#### Geologic Columns
- Arizona:
- Oldest: Metamorphic Schist
- Next: Sandstone
- Next: Shale
- Youngest: Limestone

- Utah:
- Oldest: Shale
- Next: Limestone
- Next: Sandstone
- Youngest: Shale

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Part b: Identify the units that have the same fossil in Arizona and Utah

From the diagrams:
- In Arizona, the limestone layer contains fossils (triangle symbols).
- In Utah, the limestone layer also contains fossils (triangle symbols).

Thus, the limestone layers in both Arizona and Utah contain the same type of fossil.

#### Answer for Part b:
The units with the same fossil are the limestone layers in both Arizona and Utah.

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Part c: Draw arrows on the diagram between the Arizona and Utah columns indicating which units are the same age based on fossil evidence

Based on the fossil evidence:
- The limestone layers in both Arizona and Utah contain the same type of fossil (triangle symbols), indicating they were deposited at the same time.

#### Answer for Part c:
Draw an arrow connecting the limestone layers in the Arizona and Utah columns.

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Part d: If you went to Utah, what type of rock would you expect to find below the lower shale unit with the + fossil?

In the Utah cross-section:
- The lower shale unit (with the + fossil) is directly above the limestone layer.

Thus, below the lower shale unit with the + fossil, you would expect to find limestone.

#### Answer for Part d:
Below the lower shale unit with the + fossil in Utah, you would expect to find limestone.

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Part e: Determine the history of the entire area by correlating the two cross sections using the fossils present in the units

To correlate the two cross-sections:
1. Limestone (triangle fossils): Present in both Arizona and Utah, indicating they were deposited at the same time.
2. Shale (+ fossils): Present in both Arizona and Utah, but in different positions. The + fossils in Utah are in the lower shale, while in Arizona, the + fossils are in the upper shale.
3. Sandstone: Present in both Arizona and Utah but in different positions.
4. Metamorphic Schist: Only present in Arizona, indicating it is older than any unit in Utah.

#### Combined Geologic Column:
- Oldest: Metamorphic Schist (Arizona only)
- Next: Shale (Utah only)
- Next: Limestone (correlated in both Arizona and Utah)
- Next: Sandstone (correlated in both Arizona and Utah)
- Youngest: Shale (Arizona only)

#### Answer for Part e:
The combined geologic column, from oldest to youngest, is:
1. Metamorphic Schist (Arizona only)
2. Shale (Utah only)
3. Limestone (correlated in both Arizona and Utah)
4. Sandstone (correlated in both Arizona and Utah)
5. Shale (Arizona only)

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Final Answers

1. Part a:
- Arizona: Metamorphic Schist → Sandstone → Shale → Limestone
- Utah: Shale → Limestone → Sandstone → Shale

2. Part b: The units with the same fossil are the limestone layers in both Arizona and Utah.

3. Part c: Draw an arrow connecting the limestone layers in the Arizona and Utah columns.

4. Part d: Below the lower shale unit with the + fossil in Utah, you would expect to find limestone.

5. Part e: The combined geologic column is:
- Metamorphic Schist (Arizona only)
- Shale (Utah only)
- Limestone (correlated in both Arizona and Utah)
- Sandstone (correlated in both Arizona and Utah)
- Shale (Arizona only)

Boxed Final Answer:
\[
\boxed{
\text{Metamorphic Schist (Arizona only), Shale (Utah only), Limestone (correlated), Sandstone (correlated), Shale (Arizona only)}
}
\]