Popular in Evolution of the Earth
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This 3 page Class Notes was uploaded by Ryan Neubauer on Friday October 23, 2015. The Class Notes belongs to Geography 202 at Illinois State University taught by James Day in Fall 2015. Since its upload, it has received 16 views. For similar materials see Evolution of the Earth in Geography at Illinois State University.
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Date Created: 10/23/15
Week 101 Plate Tectonics A Sea Floor 1 By the 1960 s the major features of the sea oor had become fairly well known B Continents 1 Matching Continental Coastlines 2 Continental margins 3 Geological Fit of The Southern continents C Collision Zone 1 Formed when Gondwana collided with Laurussia to form Pangea D Gondwana Sequences 1 Rock successions on different continents with closely similar fossil rock types and geological histories 2 Glossopteris Flora a Tree like that contributed to the making of coal 3 Mesosaurus a Early Permian freshwater aquatic reptile know from South Africa and South America 4 Lystrosaurus a A Permian and early Triassic mammal like reptile known from Antarctica Africa and southeast Asia 5 Glacial Deposits a Tillites i Glacier deposits ii Striations 1 Ice ow E Harry Hess and Sea Floor Spreading 1 Proposed that new sea oor lithosphere was constantly forming in and around rift valleys of mid ocean ridges and moving away in opposite directions 2 Proposed that plate motion was driven by two opposing thermal convection cells in the mantle rising beneath midocean ridges a Abnormal heat ow b Produce tensional stresses creating rift valleys at tops of ridges c Rifting generated shallow earthquakes beneath ndges d Eruption of hot water and new crustal material at ridge axes e Slow convective ow of crust laterally away from ridge causing spreading of sea oors through time F Mantle Convection 1 Upper Mantle convection as a possible Mechanism for Plate tectonics G Rift Valleys 1 Rift valleys of MidOcean ridges are sites of sea oor spreading evidenced by volcanic activity shallow earthquakes high heat ow ll Week 102 A Tuzo Wilson 1 He provide evidence that the sea oor and its features were not the same age relatively young and showed distinct age relationships with respect to positions of midocean ridges 2 Thickness and maximum age of sea oor sediments cover 3 Age relationships and features of seamounts guyots and oceanic island and seamounts chains 4 Relict Magnitization patterns of sea oor igneous rocks and marine sediments 5 He mostly documented seamounts and guyots with his team 6 No spreading a Sea oor is all the same age maximum age of sediments the same across basin versus actual pattern where the thickness and maximum age increased in age away from ridges 7 Proposed that the Hawaiian islands formed successively over a common source of magma called a hot spot a The island of Hawaii is currently located over a hotspot b Hot spots are located over mantle plumes that originate in the lower mantle and result in melting in the upper mantle and produce enormous volumes of basaltic magmaslavas i Mantle plumes and hotspots are NOT associated with spreading centers 1 lntraplate igneous centers lll Week 103 A Subduction Zpone 1 Location where olderdenser ma c sea oor lithosphere descends in the mantle beneath the edge of another converging plate 2 Its location is de ne by progressively deeper zone of earthquake foci called a Benioff Zone B Lithospheric Plate boundaries and Interactions 1 Convergent a Subduction zone marked at surface by location of oceanic trench with adjacent andesitic volcanic arcsMagmatic Arc b Collision Boundary where collision between plates of continental crust collision Orgen 2 Divergent a Positions coincide to locations of Continental rift valley or Rift valley at top of MidOcean Ridge b Processes going on crustal divergence Sea Floor Spreading formation of new oceanic crust and movement away from spreading center 3 Transform a Plates slide past oneanother across transform faults C Divergent Boundaries 1 Divergent boundaries can be midocean ridges or continental rift valleys a At these boundaries two neighboring plates MOVE AWAY from each other b Continental rift valleys are characterized by normal faulting and basaltrich volcanoes 2 New crust forms in these locationsconstructional boundades 3 Continental Rift Valleys a Aulocogen Basin i Failed rift arm 4 Triplejunctions a When three plate boundaries come together b Initially form during rifting and are the point where the boundaries between three tectonic plates and three plate margins meet 5 Red Sea Basin a Rift valley that has widened and subsided below sealeaveonsetofsea D Transform Plate Boundaries 1 San Andreas Fault