GSU GEOL 1122K - Study Guide Chapter 2 (14 pages)

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Essentials of Geology 4th edition by Stephen Marshak 2013 W W Norton Company Chapter 2 The Way the Earth Works Plate Tectonics 1 Chapter 2 The Way The Earth Works Plate Tectonics 2 In this Chapter What were Wegener s observations Paleomagnetism the key proof of continental drift Observations that led Harry Hess to sea floor spreading Three kinds of plate boundaries Plate interactions and rates of plate movement 3 Alfred Wegener German meteorologist and polar explorer Wrote The Origins of the Continents and Oceans in 1915 He hypothesized a former supercontinent Pangaea He suggested that land masses slowly move continental drift These were based on strong evidence Fit of the continents Glacial deposits far from polar regions Paleoclimatic belts Distribution of fossils Matching geologic units 4 Plate Tectonics Wegener s idea was the basis of a scientific revolution Earth continually changes Continents move split apart and recombine Ocean basins open and close His hypothesis was met with strong resistance What force could possibly be great enough to move the immense mass of a continent PowerPoint slides prepared by Rick Oches Professor of Geology Environmental Sciences Bentley University Waltham Massachusetts 5 Plate Tectonics The scientific revolution began in 1960 Harry Hess Princeton proposed sea floor spreading As continents drift apart new ocean floor forms between Continents converge when ocean floor sinks into the 1 Ocean basins open and close His hypothesis was met with strong resistance What force could possibly be great enough to move the immense mass of a continent Essentials of Geology 4th edition by Stephen Marshak 2013 W W Norton Company Chapter 2 The Way the Earth Works Plate Tectonics 5 Plate Tectonics The scientific revolution began in 1960 Harry Hess Princeton proposed sea floor spreading As continents drift apart new ocean floor forms between Continents converge when ocean floor sinks into the interior By 1968 a complete model had been developed Continental drift sea floor spreading and subduction Earth s lithosphere is broken into 20 plates that interact 6 Glacial Evidence Evidence of Late Paleozoic glaciers found on five continents Some of this evidence is now far from the poles These glaciers could not be explained unless the continents had moved 7 Paleoclimatic Evidence Placing Pangaea over the Late Paleozoic South Pole Wegener predicted rocks defining Pangea climate belts Tropical coals Tropical reefs Subtropical deserts Subtropical evaporites Fossil Evidence Identical fossils found on widely separated land Lystrosaurus A nonswimming land dwelling reptile Cynognathus A nonswimming land dwelling mammal like reptile These organisms could not have ocean PowerPoint slides prepared by Rick crossed Oches Professoran of Geology Environmental Sciences Bentley University Waltham Massachusetts Pangaea explains the distribution 8 2 Fossil Evidence Identical fossils found on widely separated land Lystrosaurus A nonswimming land dwelling