Lec23-Apr14

Lec23-Apr14 - 4/14/10 Geological processes Astro 109...

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Unformatted text preview: 4/14/10 Geological processes Astro 109 Lecture 23: Geology on Earth Volcanism April 14 Cratering Erosion Tectonics Apr. 14 Discussion QuesJon What is the main energy source for mountain building on Earth? A.  B.  C.  D.  E.  The Sun Earth’s internal heat Tidal interacJons with the Moon The solar wind None of the above Apr. 14 Apr. 14 Discussion QuesJon Earthquakes How do we study the internal structure of the Earth? A.  By drilling deep holes into the mantle and core. B.  By making theoreJcal calculaJons of the properJes of gases and liquids. C.  By analyzing how seismic waves from earthquakes propagate through the Earth. D.  By comparing Earth to other planets in the solar system. E.  By analyzes the gases and lava emiUed by volcanoes. Apr. 14 Apr. 14 Wikipedia 1 4/14/10 Seismic waves P waves S waves Apr. 14 Apr. 14 Discussion QuesJon The cores of terrestrial planets contain mostly metals because A.  the planets are made almost enJrely of metals. B.  in the protoplanetary disk, metal cores formed first and then accreted rocky crusts. C.  metals sank to the center when the planets were molten. D.  metals were created by radioacJve decay. E.  metals were carried to the center by convecJon. Apr. 14 Apr. 14 Apr. 14 Wikipedia Apr. 14 2 4/14/10 Apr. 14 Apr. 14 http://www.mapsharing.org/MS-maps/map-pages-worldmap/1-continental-map-pangea-drift.html" ConvecJon •  convecJon in the mantle is what causes the plates to move Apr. 14 Discussion QuesJon What is the source of energy that drives convecJon in Earth’s mantle? A.  B.  C.  D.  E.  Apr. 14 Plate Tectonics Apr. 14 residual heat from planetesimal collisions radioacJve decay Jdal forces from the Moon both A and B all three A, B, and C Mid ­AtlanJc Ridge Apr. 14 3 4/14/10 Mid ­AtlanJc Ridge in Iceland Discussion QuesJon Which of the following is not a correct statement of ideas from the theory of plate tectonics? A.  B.  C.  D.  E.  Apr. 14 Plates are destroyed at subducJon zones. All volcanic acJvity occurs at subducJon zones. Plates are created at mid ­ocean ridges. Earth’s crust is broken into plates. Most earthquakes occur at plate boundaries. Apr. 14 Himalayas Apr. 14 Apr. 14 FormaJon of the Himalayas Erosion wind ice http://www.cnr.vt.edu/boyer/geog1014/TOPICS/103Topo/landforms.html" Apr. 14 http://www.geology.um.maine.edu/geodynamics/AnalogWebsite/UndergradProjects2006/Chase/files/typecase.html" Apr. 14 water 4 4/14/10 Discussion QuesJon Recap The geological process of erosion is A.  B.  C.  D.  E.  much more important on the Moon than on Earth much less important on the Moon than on Earth about as important on the Moon as on Earth responsible for the lunar maria being flat responsible for a serious loss of lunar topsoil Volcanism Cratering Erosion Tectonics Apr. 14 Apr. 14 HW quesJons 2.  Describe the various ways in which the Earth’s surface is reshaped over Jme. 15. Describe the process of plate tectonics. Give specific examples of geographic features created by plate tectonics. HW QuesJon 35. Measurements of the sea floor show that the Eurasian and North American plates have moved 60 km apart in the past 3.3 million years. How far apart (in millimeters) do they move in one year? d = 60 km × 17. Why do you suppose that acJve volcanoes, such as Mount St. Helens in Washington State, are usually located in mountain ranges that border on subducJon zones? 103 m 1 km = 6 × 107 mm ￿ × ￿ 103 mm 1m ￿ t = 3.3 × 106 yr 34. IdenJcal fossils of the repJle Mesosaurus, which lived 300 millions years ago, are found in eastern South America and western Africa and nowhere else in the world. Explain how these fossils provide evidence for the theory of plate tectonics. v 35. Measurements of the sea floor show that the Eurasian and North American plates have moved 60 km apart in the past 3.3 million years. How far apart (in millimeters) do they move in one year? Apr. 14 ￿ Apr. 14 d t 6 × 107 mm = 3.3 × 106 yr = 3 mm/yr = 5 ...
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This note was uploaded on 09/15/2011 for the course PHYS 109 taught by Professor Pryor during the Spring '09 term at Rutgers.

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