Bell-ringers for SC.7.E.6.3

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What is the principle of superposition in geology?

Back

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

Front

What are fossils and how do they help in dating rocks?

Back

Fossils are the preserved remains or traces of ancient organisms. They help in dating rocks by providing relative ages; certain fossils are known to appear in specific geological time periods.

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What is radiometric dating?

Back

Radiometric dating is a method used to date rocks and minerals using the decay rates of radioactive isotopes.

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What does the term 'igneous rock' refer to?

Back

Igneous rock is formed from the cooling and solidification of molten rock (magma or lava).

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What is sedimentary rock?

Back

Sedimentary rock is formed from the accumulation and compaction of mineral and organic particles, often in layers.

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What is metamorphic rock?

Back

Metamorphic rock is formed from existing rock types that have been changed by heat, pressure, or chemically active fluids.

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How do scientists determine the relative age of rock layers?

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Scientists determine the relative age of rock layers by examining their position, the types of fossils they contain, and the geological features present.

Front

What is the significance of crystal size in rocks?

Back

Crystal size can indicate the cooling rate of the magma; larger crystals typically form from slower cooling.

Front

What is the geological time scale?

Back

The geological time scale is a system of chronological dating that relates geological strata to time, dividing Earth's history into eons, eras, periods, and epochs.

Front

What is an unconformity in geology?

Back

An unconformity is a surface that represents a gap in the geological record, where rock layers have been eroded or not deposited for a period of time.