Which boundary type is associated with volcanoes and trenches?

Which boundary type is associated with volcanoes and trenches?

• A. Divergent Boundaries
• B. Subduction Zones
• C. Convergent Boundaries
• D. Collision Zones

Answer: (B)

Volcanoes and trenches form at subduction zones. In these areas, one tectonic plate sinks beneath another. The deep surface trench marks where the subduction begins as the plate dives down. As the descending plate carries water and other volatiles into the hotter mantle, these fluids lower the melting point of the overlying mantle rocks, causing them to melt and form magma. This magma is buoyant and rises toward the surface, feeding volcanoes on the overriding plate and often creating a volcanic arc. So the combination of a surface trench and nearby volcanic activity is a hallmark of subduction zones. Divergent boundaries produce upwelling magma at mid-ocean ridges without deep trenches, and collision zones can build high mountains with volcanic activity in some settings but do not create the trench-central feature associated with subduction.

Volcanoes and trenches form at subduction zones. In these areas, one tectonic plate sinks beneath another. The deep surface trench marks where the subduction begins as the plate dives down. As the descending plate carries water and other volatiles into the hotter mantle, these fluids lower the melting point of the overlying mantle rocks, causing them to melt and form magma. This magma is buoyant and rises toward the surface, feeding volcanoes on the overriding plate and often creating a volcanic arc. So the combination of a surface trench and nearby volcanic activity is a hallmark of subduction zones. Divergent boundaries produce upwelling magma at mid-ocean ridges without deep trenches, and collision zones can build high mountains with volcanic activity in some settings but do not create the trench-central feature associated with subduction.