Fossils and Past Environments

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Geology Noun

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[jee-ol-uh-jee]

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Geology

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The science that studies Earth's physical structure, its history, and the processes that act on it.

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Example: The image shows Earth's layers and sediment deposition, illustrating geology and past environments.

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Sedimentary Rock Noun

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[sed-uh-men-tuh-ree rok]

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Sedimentary Rock

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A type of rock formed from sediment, such as sand and mud, deposited by water or air.

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Example: Sediments like sand and mud settle in layers over time to form sedimentary rock.

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Fossil Noun

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[fos-uhl]

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Fossil

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The preserved remains, or traces of remains, of ancient organisms found in rock.

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Example: A fossil of an ancient organism preserved in rock, showing how remains are embedded over time.

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Superposition Noun

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[soo-per-puh-zish-uhn]

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Superposition

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A principle stating that in undisturbed rock layers, the youngest layer is on top and the oldest is on the bottom.

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Example: The image shows layers of rock with the youngest on top, demonstrating the principle of superposition.

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Relative Age Noun

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[rel-uh-tiv eyj]

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Relative Age

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The age of a rock or fossil compared to other rocks or fossils, without determining a specific age in years.

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Example: Fossils in deeper layers are older than those in upper layers.

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Original Horizontality Noun

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[uh-rij-uh-nl hor-uh-zon-tal-i-tee]

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Original Horizontality

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A principle stating that layers of sediment are originally deposited horizontally under the action of gravity.

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Example: Layers of sediment are shown deposited horizontally under a body of water, illustrating original horizontality.

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Uniformitarianism Noun

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[yoo-nuh-fawr-mi-tair-ee-uh-niz-uhm]

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Uniformitarianism

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The principle that geologic processes that occurred in the past can be explained by current geologic processes.

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Example: Layers of sedimentary rock show how past environments can be understood by studying current geological processes.

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Body Fossil Noun

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[bod-ee fos-uhl]

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Body Fossil

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A fossil that preserves parts of an organism's body, such as bones, teeth, or shells.

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Example: This image shows a body fossil of a dinosaur, preserving its bones and structure.

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Trace Fossil Noun

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[treys fos-uhl]

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Trace Fossil

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A fossil that preserves evidence of an organism's activities, such as footprints, burrows, or droppings.

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Example: A dinosaur footprint in rock shows evidence of past movement, illustrating a trace fossil.

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Paleontology Noun

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[pey-lee-uhn-tol-uh-jee]

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Paleontology

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The branch of science concerned with the study of fossils of animals and plants.

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Example: The image shows how animal remains are buried and fossilized over time, explaining paleontology.