Geologic Time

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What is Geologic Time?

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Geologic Time is the timeline of Earth's history, divided into eons, eras, periods, epochs, and ages, used to describe the timing and relationships of events in Earth's history.

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What are Intrusive Rocks?

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

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What evidence do fossils provide about Earth's evolution?

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Fossils provide evidence of how life has changed over time and can show how different organisms are related, as well as how environments have changed.

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What is the significance of finding limestone at the top of the Himalayas?

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It indicates that the area was once covered by shallow, warm waters, showing that Earth's surface has changed significantly over time.

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What does a timeline of the Sahara Desert suggest about Earth's changes?

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It suggests that Earth's environment has changed over time, as human fossils indicate that the area was once suitable for human life.

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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 Sedimentary Rocks?

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Sedimentary rocks are formed from the accumulation and compaction of mineral and organic particles, often found in layers.

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What is the difference between Intrusive and Extrusive Rocks?

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Intrusive rocks form from magma cooling below the surface, while extrusive rocks form from lava cooling on the surface.

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What are Fossils?

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Fossils are the preserved remains or traces of ancient organisms, providing insight into past life and environments.

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What is Plate Tectonics?

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Plate tectonics is the theory that explains the movement of Earth's lithospheric plates, leading to geological activity such as earthquakes and volcanic eruptions.