answersLogoWhite

0

If this is a test question, beware! The most common answer served up by public education would be 'igneous rock'. However, the bulk of crustal rock is metamorophic. The reason for this is fairly simple: rock metamorphoses at higher temperature and pressure, both of which increase significantly with depth from the surface. Since oceanic crustal rock is on average 5 miles in depth, and continental crust is on average 30 miles in depth, the bulk of the crustal rock is exposed to great pressures and temperatures. When it is written that oceanic crust is mainly basalt, an igneous rock, and continental crust is mainly granite, also an igneous rock, it is mainly in reference to their chemical composition, not their classification by type. Warning: be prepared to back up your 'metamorphic' answer.

User Avatar

Wiki User

11y ago

What else can I help you with?