Chapter 2 Outline

Chapter 2 Outline - 12 plates Theory of Plate Tectonics...

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2 Theory of Plate Tectonics: describes the movement of plates and the forces acting between them; explains the distribution of many large-scale geological features that result form movements at plate boundaries 2 The Discovery of Plate Tectonics Tectonics: Greek for “builder” 1960s basic ideas put together but started much earlier Continental Drift 2 Continental Drift: large-scale movement of continents over the globe 2 Eduard Suess end of 19 th century, put continents together to form Gondwananland e 1915 Alfred Wagner wrote abt break up of continents 2 Laid out remarkable similarity of rocks, geologic structures, and fossils on opposite sides of atlantic 2 Pangea: supercontinent that broke up into the continents as we know them today 2 Not believed by all b/c physicists tried to convice geologists that Earth’s outer layers were too rigid for continental drift Seafloor Spreading 2 Wagner thought continents dragged along by tidal forces of sun and moon 2 Seafloor Spreading: the mechanism by which new seafloor is created along the rift at the crest of a mid-ocean ridge as adjacent plates move apart. The crust separates along the rift and new seafloor forms as hot new crust upwells into these cracks. The new seafloor spreads laterally away from the rift and is replaced by even newer crust in a continuing process of plate creation 2 1928 Arthur Holms, British 2 Evidence mapping of the undersea Mid-Atlantic ridge 2 Most earthquakes generated here meaning still active 2 Early 1962 Harry Hess and Robert Diets proposed that crust separates along ridges in mid-ocean ridges and new seafloor forms by upwelling of new crust into these cracks The Great Synthesis: 1963-1968 2 Ring of Fire geologists recognized seafloor recycling along this Pacific Ocean area 2 1965 Tuzo Wilson characterized three basic types of boundaries 2 The Mosaic of Plates Each plate moves as distinct rigid unit, riding on asthenosphere, which is also in motion 2 Plate boundaries 2 Divergent Boundaries: plates move apart and new lithosphere is created (plate area increases)
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This note was uploaded on 03/31/2008 for the course GLG 111 taught by Professor Kuentz during the Fall '05 term at Miami University.

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Chapter 2 Outline - 12 plates Theory of Plate Tectonics...

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