Earth Sciences 1023A/B Lecture 11: plate boundaries
3 Mar 2016
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Document Summary
The new global tectonics of the 1970"s earth"s ultimate recycling program. Polar wander magnetic north pole moves, proves magnetic field is dynamic. Harry hess seafloor spreading, convection in the mantle that causes trenchs is what drives continental drift. Morley, vine and matthews magnetic stripes, can tell in the ocean floor the patterns of magnetized rocks in both normal and reversed. Earth"s surface is divided into rigid lithospheric plates. New oceanic lithosphere is created at mid-ocean ridges production. Oceanic lithospheric is destroyed at deep-sea trenches (subduction zone) why the planet isn"t growing, ocean crust is destroyed at subduction zone and created at divergent boundaries. This process largely explains the global distribution of earthquakes and volcanoes there is a lot of force and friction on subduction boundaries. Outer part of the earth approx 100 km thick. Includes the crust and part of the upper mantle. Arbian, indian, scotia, caribbean, nazca, cocos, juan de fuca, philippine sea.
