1. Describe what happens to Plate A as it collides with Plate B?
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Plate A, which is denser (usually oceanic crust), is forced beneath Plate B (usually continental crust).
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This process is called subduction.
2. What do you think may happen to the leading edge of Plate A as it continues to move downward? Why?
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As Plate A sinks deeper into the mantle, the leading edge melts due to high temperature and pressure, as well as water released from minerals.
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This melting occurs in the subduction zone.
3. What do you call this molten material?
4. What is formed on top of Plate B?
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The magma rises through cracks in Plate B, leading to the formation of a volcanic arc (if on land) or island arc (if in the ocean).
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In addition, mountain ranges and volcanoes are formed.
Summary:
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Plate A is subducted under Plate B.
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The leading edge melts as it moves downward due to heat and pressure.
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The molten material is called magma.
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On Plate B, volcanoes and mountain ranges form.