WRS Earths History Vocabulary

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What are Molds and Casts?

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Molds and Casts are fossil types formed when an organism dies, is buried, and dissolves, leaving a cavity (mold) that can be filled with minerals to create a replica (cast) of the organism.

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What are Fossils?

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Fossils are the preserved remains or evidence of living things from the past, including bones, shells, and imprints.

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What is Catastrophism?

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Catastrophism is the idea that life on Earth changes violently and suddenly due to catastrophic events, such as natural disasters.

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What are Petrified Fossils?

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Petrified Fossils occur when organic matter is completely replaced by minerals, turning the fossil into stone.

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What are Index Fossils?

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Index Fossils are the remains of plants and animals that lived for a limited period and are used to identify and date the layers of rock in which they are found.

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What is the Law of Superposition?

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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 are Trace Fossils?

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Trace Fossils are geological records of biological activity, such as footprints, burrows, or feces, rather than the remains of the organism itself.

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What is Uniformitarianism?

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Uniformitarianism is the principle that the processes that shaped the Earth in the past are the same as those we observe today.

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What is an Unconformity?

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An Unconformity is a gap in the geological record that represents a period of time where no sediment was deposited or where erosion occurred.

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What is Carbon Film?

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Carbon Film is a type of fossilization where a thin layer of carbon remains after an organism decays, leaving a detailed impression of its structure.