What happens at an oceanic-continental convergent boundary?

What happens at an oceanic-continental convergent boundary?

• A. The oceanic plate subducts beneath the continental plate
• B. The continental plate subducts beneath the oceanic plate
• C. Two continental plates slide past each other
• D. New ocean floor is created

Answer: (A)

At an oceanic-continental convergent boundary, the oceanic plate subducts beneath the continental plate because oceanic lithosphere is denser. As the oceanic slab sinks, it creates a deep offshore trench and carries water into the mantle, which lowers the melting point and generates magma that rises to form a continental volcanic arc. This setting also produces powerful earthquakes and deformational features as the plates interact and grind together. The other scenarios don’t fit this boundary type: continental plate subducting beneath oceanic plate would require the lighter continent to dive, which doesn’t happen; two continental plates sliding past each other describes a transform boundary with horizontal motion and no subduction; and creation of new ocean floor occurs at divergent boundaries like mid-ocean ridges.

At an oceanic-continental convergent boundary, the oceanic plate subducts beneath the continental plate because oceanic lithosphere is denser. As the oceanic slab sinks, it creates a deep offshore trench and carries water into the mantle, which lowers the melting point and generates magma that rises to form a continental volcanic arc. This setting also produces powerful earthquakes and deformational features as the plates interact and grind together.

The other scenarios don’t fit this boundary type: continental plate subducting beneath oceanic plate would require the lighter continent to dive, which doesn’t happen; two continental plates sliding past each other describes a transform boundary with horizontal motion and no subduction; and creation of new ocean floor occurs at divergent boundaries like mid-ocean ridges.