EVANTH 101D Lecture Notes - Lecture 13: Biostratigraphy, Paleomagnetism, Tropical Vegetation
13 Oct 2016
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10/13/16: geologic time - earth is 4. 5 bya. Supernova began to coalesce: no rocks on earth, but asteroids from space may hit, cenozoic - new life, precambrian = proterozoic + archean + hadean (eons, paleozoic - massive radiation of marine life. Continental drift: continents rest on tectonic plates that float on the molten core and move very slowly, no old rocks because they eventually get subducted and melted and made into new rocks, plate movement causes mountains and earthquakes. Plate tectonics: evidence of connected continents, same rocks on previously connected continents, extinct animals whose fossils have been on different continents, pangea separated at ~150 ma, became supercontinents laurasia (eurasia) and gondwana (africa, Antarctica cooler and icy: miocene begin cooling of earth, cooler temp usually = dryer temp, tropical regions become smaller area near equator, as move away from equator, become temperate regions.
