5.1 Geologic Time Practice Flashcard

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What is the Law of Superposition?

Back

The Law of Superposition states that in undisturbed sedimentary rock layers, the oldest layers are at the bottom and the youngest layers are at the top.

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What does the Law of Original Horizontality state?

Back

The Law of Original Horizontality states that layers of sediment are originally deposited horizontally under the action of gravity.

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What is the Law of Cross-Cutting Relationships?

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The Law of Cross-Cutting Relationships states that if a geological feature cuts through another, the feature that has been cut is older.

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What does the Law of Inclusions indicate?

Back

The Law of Inclusions states that any rock fragments that are included in another rock must be older than the rock in which they are included.

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How can the relative age of rock layers be determined?

Back

The relative age of rock layers can be determined using the Law of Superposition, the Law of Original Horizontality, and the Law of Cross-Cutting Relationships.

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What is an intrusion in geology?

Back

An intrusion is a body of igneous rock that forms when magma cools and solidifies beneath the Earth's surface.

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What is the significance of fossils in determining geological time?

Back

Fossils help in determining the relative ages of rock layers and can indicate the environment in which the layers were formed.

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What is the difference between absolute age and relative age?

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Absolute age is the actual age of a rock or fossil in years, while relative age is the age of a rock or fossil in comparison to other rocks or fossils.

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What is a geological event?

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A geological event is a significant occurrence that affects the Earth's structure, such as volcanic eruptions, earthquakes, or the folding of rock layers.

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What is the purpose of a geologic time scale?

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The geologic time scale is used to organize Earth's history into different time intervals based on significant geological and biological events.