ERTH 2403 Lecture 4: Lecture 4
2 Sep 2016
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Lecture 4 earth structure and plate tectonics: convergent plate boundaries. Continental to continental crust collision = mountain building: ocean to ocean, denser crust subducts, trenches, volcanism, deep ,intermediate &shallow earthquakes. Ocean to ocean convergence: volcanic island arcs basaltic. Ocean to continental convergence: volcanic arc on continent andesitic. Continental to continental: major collision of continents, crustal thickening, mountain building, earthquakes, transform fault plate boundaries. Intraplate: under oceanic crust hawaii, under continental crust yellowstone national park. Mantle plumes: column of superheated mantle generated at the core-mantle boundary. Hot spots are surface expression of magma rising from the mantle plumes from a stationary point or source. Bathymetry: the study of ocean floor contours; bathy = deep; meter = measure. Earliest bathymetry in the mediterranean by the greek posidonius (85 bc) Un 1818 sir james clark ross: sounding of 4893 meters in the south atlantic. In 1870, hms challenger: 492 bottom sounding (confirmed the discovery of the mid-atlantic.
