EAS 1540 Lecture Notes - Lecture 5: Divergent Boundary, Plate Tectonics, Continental Crust
15 Dec 2016
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Document Summary
Lec 5 - wed 9/7 - marine geology part ii. Atlantic ocean, pacific ocean - mature divergent boundary (mid ocean-ridges) East africa rift zone - new divergent plate boundary. Ocean crust is more dense so it gets pushed down into the mantle. Plate that gets subducted (pushed down) is the one that is furthest from its respective spreading center, and is older/cooler/more dense. Builds mountains because no boundary want to give up. Hawaiian islands - big island is still being built (magma coming to the surface to expand island) Mantle plume is fixed, pacific plates moves, new islands gets formed, plate moves, island gets formed. Qualitative look at marine sediments a. b. c. Paleo-temperatures and biological productivity from analysis of sediments. Example of applying sediment core analysis to reconstructing results from a meteor impact. Records a lot of past earth changing events. Thickest around continents - due to erosion from mountains.
