Question

1. in the pacific ocean, there is a plate boundary between two tectonic plates, the pacific plate, which contains some of the oldest oceanic crust on earth, and the mariana plate. the mariana trench, the deepest oceanic trench on earth, is located at this boundary. nearby, there is an arc of volcanic islands called the mariana islands. based on this information, what type of plate boundary is this? how do you know?

Explanation:

This is a convergent (oceanic-oceanic subduction) plate boundary. Key evidence includes:

1. The presence of the Mariana Trench, a deep oceanic trench formed when denser, older oceanic crust (Mariana Plate) subducts beneath the younger Pacific Plate.
2. The arc of volcanic Mariana Islands, which form as the subducted crust melts, and magma rises to the surface to create volcanic islands.

Answer:

This is an oceanic-oceanic convergent (subduction) plate boundary. We know this because:

• The Mariana Trench (a deep oceanic trench) forms where the older, denser Mariana Plate subducts under the Pacific Plate.
• The volcanic Mariana Islands arc forms from magma generated by the melting of the subducted crust.