EPS 20 Lecture Notes - Lecture 9: Japan Trench, Himalayas, San Andreas Fault
26 Apr 2016
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1912- alfred wegener saw continents t, mountain belts t, and fossils t: named his theory continental drift, did not have a physical model/mechanism to prove his theory. Began in wwii due to submarine technology. Periodic reversals of the earth"s magnetic eld are recorded as stripes. Earth"s magnetic switches back and forth over time (every hundreds of thousands or millions of years) Creating new oceanic plates and the contents were moving away from each other. Found that earthquakes occurred along these ridges and along the edges of continents (continental shelves) Larger plates are: north american, eurasian, paci c, !1: the plates are rigid and all the deformation occurs at the edges of the plates (mainland china is an exception) Using oceanic record we can wind back the plates to see how the plates have been moving. Pangea supercontinent existed during the early jurassic and then the continents drifted apart. Divergent: established mid-ocean ridge, new rift zone, new ocean, normal faults.
