EESC1180 Lecture Notes - Lecture 3: Outer Core, Asthenosphere, Forearc
19 Sep 2017
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Document Summary
When dense basalt hits continental material since it"s denser it gets pushed down. Subduction: the process of material being pushed down. Subduction zone: area where material gets pushed down. Deep sea trenches: old pacific oceanic crust is getting subducted and destroyed. Published origins of continents and oceans with theory of continental drift. Can"t glaciate over the ocean because there"s nowhere for ice to build. Found the coal swamps, desert sands, salt deposits, and reef fossils in rocks from the time and saw that they matched up with the countries that used to be together. Glossopteris: lived across all continents (couldn"t swim so it makes sense that they were all together) Cynognathus, lystrosaurus, and mesosaurus lived across continents as well. Archean crust, proterozoic mountain belts both line up. Shows angle of magnetic field lines coming into the earth. Paleomagnetic declination is really different than today"s. Curie point: when temp of lava gets below the point where minerals start to crystalize.
