Fossils and Stratigraphy Flashcard

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What is a fossil?

Back

A fossil is the preserved remains or traces of ancient organisms, typically found in sedimentary rock.

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What is stratigraphy?

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Stratigraphy is the branch of geology that studies rock layers (strata) and layering (stratification).

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What does the Law of Superposition state?

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

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What is half-life in the context of radioactive decay?

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Half-life is the time required for half of the atoms in a radioactive sample to decay into another element.

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What is radiometric dating?

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Radiometric dating is a method used to date materials by comparing the abundance of a radioactive isotope to its decay products.

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What are inclusions in geology?

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Inclusions are fragments of one rock type that are contained within another rock type, indicating that the included rock is older.

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What is an unconformity?

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An unconformity is a surface that represents a gap in the geological record, where rock layers have been eroded or not deposited for a period of time.

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How do scientists determine the relative age of rock layers?

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Scientists determine the relative age of rock layers by using principles such as superposition, cross-cutting relationships, and fossil correlation.

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What is the significance of index fossils?

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Index fossils are 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 the difference between relative age and absolute age?

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Relative age is the age of a rock layer compared to other layers, while absolute age is the actual age of a rock layer in years.