Geologic Time

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What is Geologic Time?

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Geologic Time refers to the vast time scale used by geologists and other Earth scientists to describe the timing and relationships of events in Earth's history.

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What is the Law of Superposition?

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The Law of Superposition states that in any undisturbed sequence of rocks, the oldest layers are at the bottom and the youngest layers are at the top.

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What are fossils?

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Fossils are the preserved remains or traces of ancient organisms, often found in sedimentary rock.

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What is an intrusive rock?

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Intrusive rocks are formed from magma that cools and solidifies beneath the Earth's surface.

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What is a half-life?

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

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What is the difference between intrusive and extrusive rocks?

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Intrusive rocks form from magma that cools slowly underground, while extrusive rocks form from lava that cools quickly on the surface.

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What is a sedimentary rock?

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Sedimentary rocks are formed from the accumulation and compaction of mineral and organic particles.

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What is the significance of trilobites in geology?

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Trilobites are important index fossils used to date and correlate the age of rock layers.

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What does the term 'era' refer to in geologic time?

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An era is a major division of geologic time, typically lasting tens of millions of years.

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What is the difference between relative dating and absolute dating?

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Relative dating determines the sequence of events, while absolute dating provides a specific age or date for an event.