Getting Down to Business: Plate Tectonics
What is a collisional margin? What is a passive margin?
We know from a wide range of different studies that the Earth is not a completely solid sphere, but instead consists of a series of different layers ranging in composition that dictates the way they react when forces are applied to them. The outermost layers are very different with regard to composition and density from the innermost layers of the Earth. A generalized segregation of the Earth recognizes these three primary units: crust, mantle, and core.