Intro to American Mountain Geology (orogeny)

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Question 1: Are volcanoes often made where one plate subducts below another plate?

• No

• Yes

Answer explanation

Yes. The top plate develops cracks through which magma flows to make a volcano.

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Are the sides of a volcano made bigger by cooled lava?

• No

• Yes

Answer explanation

Yes. Hot lava cools to become a volcano’s sides.

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NGSS.HS-ESS2-1

Did a "hot spot" (mantle plume) make the Hawaiian Islands?

• No

• Yes

Answer explanation

Yes. As the Pacific plate moves past a hot spot, different parts of the Pacific plate get volcanoes.

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Are the newest Hawaiian Islands located between the oldest Islands?

• No

• Yes

Answer explanation

No. The age drops moving NW to SE, which is consistent with the "hot spot" theory.

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Are the Rocky Mountains more than 100 million years old?

• No

• Yes

Answer explanation

No. They’re young (80 million years old). Old is over 100 million years old.

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Did the Rocky Mountains form when another continent collided with what is now the Western US?

• No

• Yes

Answer explanation

No. It formed when an oceanic crust and its plate subducted (went below) the North American plate.

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Are the Rocky Mountains older than the Appalachian Mountains?

• No

• Yes

Answer explanation

No. The Rocky Mtns are taller because they are 1/4 the age of the Appalachian Mountains.

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NGSS.HS-ESS1-5

Did the Appalachian Mountains form when another continent collided with what is now the Eastern US?

• No

• Yes

Answer explanation

Yes. When continents were merging to form Pangaea, what is now North Africa collided with what is now the Eastern US.

Tags

NGSS.HS-ESS1-5

NGSS.HS-ESS2-1