Geologic Time Scale

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What is the Geologic Time Scale?

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A system of chronological dating that relates geological strata to time, used to describe the timing and relationships of events in Earth's history.

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NGSS.MS-ESS1-4

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What is an unconformity in geology?

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A surface of contact between two groups of unconformable strata, indicating a gap in the geological record.

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NGSS.MS-ESS1-4

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What is a Non-conformity?

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A type of unconformity where sedimentary rocks are deposited on top of eroded igneous or metamorphic rocks.

Tags

NGSS.MS-ESS1-4

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What is a Disconformity?

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A type of unconformity where layers of sedimentary rock are parallel but there is a gap in the geological record.

Tags

NGSS.MS-ESS1-4

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What is an Angular unconformity?

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A type of unconformity where tilted or folded sedimentary rocks are overlain by younger, more flat-lying strata.

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NGSS.HS-ESS2-1

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What does 'absolute age' mean in geology?

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The exact age of a rock or fossil, determined through methods like radiometric dating.

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What is 'relative age' in geology?

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The age of a rock or fossil in comparison to other rocks or fossils, determined by their position in the geological record.

Tags

NGSS.MS-ESS1-4

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What are index fossils?

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Fossils of organisms that were widespread but only existed for a short period, used to date and correlate the age of rock layers.

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What is Uniformitarianism?

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The principle that the same geological processes that operate today also operated in the past, helping to explain Earth's history.

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NGSS.MS-ESS3-1

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What is Catastrophism?

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The theory that Earth's features are the result of sudden, short-lived, and violent events, such as natural disasters.

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NGSS.MS-ESS3-2