GEO 101 Lecture 21: Review of section
8 Mar 2017
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Document Summary
Normal: comes out of the south pole and wraps around the earth. Reverse: flip earth"s magnetic field; north pole and wraps around to the south: how to use a magnetic record to identify mid-ocean ridges. Mid-ocean ridges/spreading centers: where there is/where you can draw a point/line of symmetry. The key is the identification of symmetry: oldest oceanic crust versus oldest continental crust, oldest oceanic crust: about 200 million years, oldest continental crust: about 4 billion years. Emily-paige montgomery epmontgomery@crimson. ua. edu: earth"s compositional layers versus rheological layers, compositional layers. Where two plates are moving away from one another (spreading center) Between ocean plates: mid-ocean ridge (seafloor spreading) Constructive: making new plate material: convergent (destructive) Where two plates are running into one another. Destructive: destroying plate material: transform (conservative) Where two plates are moving past one another, side by side. Plate material is neither created or destroyed.
