The continental crust is the layer of igneous, sedimentary, and metamorphic rocks which forms the continents and the areas of shallow seabed close to their shores, known as continental shelves.
Oceanic crust is the part of Earth's lithosphere that surfaces in the ocean basins. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium.
a convergent boundary is also known as a destructive plate boundary.is an actively deforming region where two (or more) tectonic plates or fragments of lithosphere move toward one another and collide.