Geological_Sciences_1100[3]

Geological_Sciences_1100[3] - Earths structure 28/10/2010...

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Unformatted text preview: Earths structure 28/10/2010 14:36:00 Plate Tectonics Discrete parts of the Earths shell that are distinguishable from each other Where plates meet, they either push against each other or move away This is where geologic action happens!!! Theory of Plate Tectonics Roots of theory lie in Continental Drift Formulated by Alfred Wegener PANGEA! o Supercontinent o Formed 300 million years ago o Broke up 200 million years ago The fossil evidence o Mesosaurusextinct reptile, like alligator, find fossils in South America and South Africa o Glossopterisplant o Lots of other examples Evidence from rock type and structural similaritiesAppalachians and Caleodonides o How could they form in two separate locations? Gondwanalandsouthern land masses (India, South America, Africa, Antarctica, Australia) o Iron rich sedimentary rocks on top of coal rocks on top of marine rocks, then basalt Abundant glacial rocks Plate Tectonics continued 28/10/2010 14:36:00 Problems with Continental Drift No plausible explanation of why continents moved Continents plowed through oceanic crust 28/10/2010 14:36:00 Rodinaanother super continent before Pangea Decompression meltingpressure goes down and rock starts to melt hydrothermal activity at the midocean ridges, sea water soaks up into the rock, gets heated and buoyant wants to rise again and is discharged form the sea floor Plate Tectonics 28/10/2010 14:36:00 stable sheets are lithospheric plates\\ the occurance of earth quakes under the surface follows the path of the colliding sheets/plates, it doesnt continue below this because the heat does not allow fricition between the sheets Plates move along Plate Boundaries Divergent Convergent Transform fault Divergent Boundaries Seafloor spreading New crust cools over time and sinksgets harder and more dense Paleomagnetism Lines are parallel Subsidence of the seafloor or rising sea level Fringing reefvolcano sticking out above water surface, forms reef around it Barrier reefcrust sinks lower and lower, looks like sea level gets higher Atoll: reef rings with lagoons in the center The sea floor actually sinks Convergent Boundaries Question 8.24 Subduction of one plate beneath another Oceanic crust is most dense than continental crust so it goes beneath Wadati-Benioff Zone Subduction happens with sheets Tranform Fualt Boundaries Crust just moves past each other San Andreas Fault Evaluating Plate Tectonics Hot spotcenters of volcanic activity that stay in the same spot for millions of...
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This note was uploaded on 09/14/2011 for the course GEO 1010 taught by Professor Rogers during the Spring '11 term at Missouri (Mizzou).

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Geological_Sciences_1100[3] - Earths structure 28/10/2010...

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