What happens at a Subduction Zone?

What happens at a Subduction Zone?

• A. Two plates slide past each other
• B. One plate is forced beneath the other into the mantle
• C. The mantle melts completely
• D. The crust thickens and forms mountains

Answer: (B)

At a subduction zone, one tectonic plate is forced beneath another into the mantle. This happens because the sinking plate (usually oceanic crust) is denser than its neighbor. As it descends, water released from the slab lowers the melting point of the surrounding mantle, causing partial melting and magma that can rise to form volcanoes on the overlying plate. The movement also produces strong earthquakes where the plates interact. So the defining feature is the sinking of one plate into the mantle. It’s not about plates simply sliding past each other, nor about the mantle melting completely, and while it can be linked to mountain-building in some contexts, the essential idea is the subducting plate descending into the mantle.

At a subduction zone, one tectonic plate is forced beneath another into the mantle. This happens because the sinking plate (usually oceanic crust) is denser than its neighbor. As it descends, water released from the slab lowers the melting point of the surrounding mantle, causing partial melting and magma that can rise to form volcanoes on the overlying plate. The movement also produces strong earthquakes where the plates interact. So the defining feature is the sinking of one plate into the mantle. It’s not about plates simply sliding past each other, nor about the mantle melting completely, and while it can be linked to mountain-building in some contexts, the essential idea is the subducting plate descending into the mantle.