Relative Dating of Fossils
Explore the principles of relative dating and their application to understanding Earth's history through fossils.
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Relative Dating of Fossils
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Read each question carefully and answer to the best of your ability. For multiple-choice questions, select the best option. For short answer and fill-in-the-blank questions, provide concise and accurate responses.
1. Which principle of relative dating states that in an undisturbed sequence of sedimentary rock layers, the oldest layers are at the bottom and the youngest layers are at the top?
Principle of Cross-Cutting Relationships
Principle of Superposition
Principle of Original Horizontality
Principle of Faunal Succession
2. An index fossil is a fossil that is geographically widespread and existed for a short period of geologic time. What is the primary use of index fossils in relative dating?
To determine the absolute age of a rock layer.
To correlate rock layers across different locations.
To identify the type of rock present in a layer.
To understand the depositional environment of the rock.
3. The Principle of states that geologic features that cut across rock layers, such as faults or igneous intrusions, are younger than the layers they cut through.
4. An unconformity represents a gap in the geologic record, often due to erosion or a period of non-deposition. A is an unconformity where sedimentary rocks lie above and below an erosional surface, but the layers are parallel.
5. Observe the image below depicting several geological layers and a fault. Using the principles of relative dating, describe the sequence of events that led to the formation of this geological cross-section. Clearly identify which layers are older or younger relative to each other and the fault.
6. The Principle of Original Horizontality suggests that sedimentary rocks are originally deposited in horizontal layers.
True
False
7. Radioactive dating is a method of relative dating.
True
False
Match each term on the left with its definition on the right.
8. Disconformity
a. Surface between tilted or folded sedimentary rocks and overlying horizontal sedimentary rocks.
9. Nonconformity
b. Surface between younger sedimentary rocks and older igneous or metamorphic rocks.
10. Angular Unconformity
c. Surface between parallel sedimentary layers that represents a period of erosion or non-deposition.