Plate Tectonics - Lesson 4 - Part 2 of 8

Planet of Man Series -- Jigsaw Fit (30minutes) Host; Tuzo Wilson Plate Tectonics - Lesson 4 - Part 2 of 8 •Early 70's plate tectonics -- enigma of mountains discovered with the theory of plate tectonics •Animation illustrating the slabs of individual plates from around the world. •Crust 60 miles thick •Isostatic rebound from the last ice age. • Hudson Bay is distingusished from this process by a indisntct shoreline and raised beach's •Plate name -- Euarasian Indo-Australian, African, American , Antarctic, Nazca, Pacific Plates. • Rock Types - Basalt at the tops of the spreading boundaries, upper layer of the plate, Perioditite (magnesium rich) lower layer of the plate. •Underwater eruption -- lava come into contact with the cold water forms pillow like shapes "Pillow lava" •Footage showing underwater eruptions. •Iceland -- entirely created from the spreading ridge of an active zone. •Iceland Geothermal uses • Mid-Atlantic oceanic ridge follows the shorelines of both Africa and South America. 200 million years to open to its current width. •Red Sea clearly shows also how Africa and Arabia fitted together/. •East Africa -- Great Rift Valley, early separation of this process like the Red Sea separation. The entire Rift Valley has volcanism. •Transform fault -- no mountains and no volcanoes but earthquakes are produced. It's the result of plates sliding past one another. These intense earthquakes occur mostly in the deep ocean basins. But sometimes they come on the continent -- San Andres Fault one example 700 miles long. •Animation showing the transform fault movement. •San Francisco earthquake lies along the San Andreas fault. •Footage of the 1906 earthquake •Entire city was destroyed