Unit 7: Geologic Time Flashcard Review

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What is a cast fossil?

Back

A cast fossil is formed when a mold fossil fills up with minerals, creating a replica of the original organism.

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What is a fossil?

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A fossil is the preserved remains or impression of a once-living organism.

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What is a mold fossil?

Back

A mold fossil is a type of fossil that forms when an organism leaves an impression in sediment, which hardens into rock.

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What does the law of superposition state?

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The law of superposition states that in undisturbed layers of rock, the oldest layers are at the bottom and the youngest are at the top.

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What is the law of cross-cutting relationships?

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The law of cross-cutting relationships states that a geological feature (like a fault or intrusion) that cuts through another is younger than the feature it cuts.

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What is permineralization?

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Permineralization is a process where minerals fill the pores of organic material, preserving its structure, often seen in trees and marine animals.

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What is a trace fossil?

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A trace fossil is a type of fossil that provides evidence of the activity of an organism, such as footprints or burrows.

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What is carbonization in fossils?

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Carbonization is a process where organic material is compressed and leaves a thin film of carbon, often seen in leaves and soft-bodied organisms.

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What are original remains?

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Original remains are the actual preserved parts of an organism, such as bones, teeth, or soft tissues, often found in ice or amber.

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What is the significance of fossils in geology?

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Fossils provide important information about the history of life on Earth, past environments, and the age of rock layers.