ENVIR ST 106 Study Guide - Gabbro, Seafloor Spreading, San Andreas Fault
30 Oct 2014
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Document Summary
As plates collide and separate they impact the rocks. The same type of rocks are on the borders of different continents. Lithosphere and asthenosphere: the outer solid layer is the lithosphere varies in thickness thicker on average under continents. The layer below the lithosphere is the asthenosphere high temperatures and moderate confining pressures that allow the rock to flow plastically under stress. Hot spots: use mantle hot spots to monitor rates and directions of plate movement. Polar wander paths:magnetized rocks of diff ages on a single continent may point to very diff apparent magnetic pole positions. Polar-wander curve: the reulting curve, showing the apparent movement of the magnetic pole relative to the continent as a function of time. The poles have stayed the same, but the continents moved, so the rocks give a good idea of the paths of the continents. Continents move with oceanic crust, not through it. Pull of sinking lithospheric plate (slab) at subduction.
