BM Review 3: Geology

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What is a basalt intrusion?

Back

A basalt intrusion is a geological formation where molten basalt rock has pushed into existing rock layers and solidified, typically occurring relatively recently in geological time.

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What is a trace fossil?

Back

A trace fossil is an imprint or evidence of the activity of a living organism, such as footprints, burrows, or nests, rather than the organism itself.

Front

What can scientists infer from finding a fish fossil in the desert?

Back

Scientists can infer that the area was once covered by water, indicating a different environmental condition in the past.

Front

How do you order rock layers from youngest to oldest?

Back

The order of rock layers from youngest to oldest is determined by the principle of superposition, where the oldest layers are at the bottom and the youngest are at the top.

Front

What are the two main traits of the best index fossils?

Back

The best index fossils are widespread (abundant) geographically and have a short lifespan, making them useful for dating rock layers.

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What is the principle of superposition in geology?

Back

The principle of superposition states that in an undeformed sequence of sedimentary rocks, the oldest layers are at the bottom and the youngest layers are at the top.

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What is a mold fossil?

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A mold fossil is a type of fossil that forms when an organism leaves an impression in sediment, which later hardens, creating a negative imprint of the organism.

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What is a cast fossil?

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A cast fossil is formed when a mold fossil is filled with minerals or sediment, creating a three-dimensional replica of the original organism.

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What is the significance of index fossils in geology?

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Index fossils are used to identify and date the relative age of rock layers, as they indicate specific time periods in Earth's history.

Front

What is the difference between a true form fossil and a trace fossil?

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A true form fossil is the actual remains of an organism, such as bones or shells, while a trace fossil records the activity or behavior of an organism.