Plate Tectonics A Brief Overview The Earths Plates
Plate Tectonics A Brief Overview
The Earth’s Plates http: //www. nature. nps. gov/geology/usgsnps/pltec 2. html
Layers of the Earth • Chemical • Physical http: //www. burkemuseum. org/static/geo_history_wa/The%20 Restless%20 Earth%20 v. 2. 0. htm
Layers of the Earth and Food • Lithosphere – Chocolate: when it’s cold, it’s hard and breaks, but as it warms up it can bend and eventually melt • Asthenosphere – Honey: it’s thick and sticky, but it flows • Mantle – Crumbled cookies: it’s solid but can move and convect • Outer core – Milk: liquid • Inner core – Peach pit: solid
Plate Boundaries Stern, R. J. , Subduction zones, Rev. Geophys. , 40(4), 1012, doi: 10. 1029/2001 RG 000108, 2002
Margins: Divergent • Mid-Ocean Ridges – Mid Atlantic Ridge http: //www. phschool. com/atschool/phsciexp/internet_acti vity/cfd-1014_midocean. html • Continental Rifts – East African Rift Valley http: //www. talk. co. uk/reference/encyclopaedia/hutchi nson/m 0006339. html
Margins: Convergent • Ocean-ocean subduction – Island arc: Marianas http: //www. see. leeds. ac. uk/structure/dynamicearth/subduction/cordillera_islandarc. htm
Margins: Convergent • Ocean-continent subduction – Volcanic arc and mountains: Andes http: //www. see. leeds. ac. uk/structure/dynamicearth/subduction/cordillera_islandarc. htm
Margins: Convergent • Continent-continent collision – Large mountain range: Himalayas and Alps http: //www. unil. ch/igp/page 23575_en. html
Margins: Transform • Marine – Transform faults: • Mid Atlantic Ridge • Terrestrial – Strike-slip faults: • San Andreas Fault http: //geomaps. wr. usgs. gov/archive/socal/geology/inland_empire/socal_faults. html
Evidence for Plate Tectonics • Fit of the continents • Sea floor ages and magnetic anomalies – evidence of ocean spreading • Paleontology – similar species on now widely separated continents • Seismicity and volcanism concentrated at plate boundaries – evidence of oceanic subduction • Hot spot tracks – record movement of plates over “fixed” hot spot • GPS
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