History of Earth vocab flashcardz

Front

A record of the geologic events and life forms in Earth’s history.

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Geological Time Scale

Front

The geologic principle that states that in horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the layer below it.

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Law of Superposition

Front

The process of determining the age of an object using the half-life of one or more radioactive isotopes.

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Radioactive Dating

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One of the units of geologic time into which geologists divide eras.

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Period

Front

A gap in the geologic record that shows where rock layers have been lost due to erosion.

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Unconformity

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The time span of a significant event in Earth's history, such as the formation of a mountain range or the extinction of a species.

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Era

Front

The age of an object in years, determined through methods like radioactive dating.

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Absolute Age

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The age of an object in relation to other objects, without specifying an exact age.

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Relative Age

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A major event in Earth's history that results in a significant loss of biodiversity, such as the extinction of dinosaurs.

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Mass Extinction

Front

The division of the geological time scale into smaller units, which are subdivisions of eras.

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Period