Lecture10 platetectonics

Plate Tectonics Tectonic Plates of the Earth

How can we explain the rock cycle? ,[object Object],[object Object],[object Object],[object Object]

Earth as a jigsaw puzzle ,[object Object],[object Object]

Wegener’s contribution ,[object Object],[object Object]

Theory of fixed continents ,[object Object],[object Object],[object Object],[object Object],[object Object]

Evidence against fixed continents Matching edges Matching geology

Bathymetry of the ocean floor continental shelf abyssal plain trench mid ocean ridge

Thickness of the Sediment x 550 m x 102 m x 18 m x 112 m x 430 m 35 m x

Radiometric dating Red = younger, green = older

Plate tectonics ,[object Object],[object Object],[object Object],[object Object],[object Object]

Making crust ,[object Object],[object Object],[object Object],Magma Ridge New crust Sea-floor spreading Asthenosphere Lithosphere Sea-floor spreading

[object Object],[object Object],[object Object],Destroying crust Asthenosphere Subducting plate Trench

Making crust + destroying crust = conveyor belt system = rock cycle (sort of) Convection or Buoyancy Ridge push Slab pull Convection cell in mantle

Where are ridges & trenches? ridges trenches

Geologic Excitement at Tectonic Plate Boundaries

3 Major plate boundaries ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

1. Spreading boundaries ,[object Object],[object Object],[object Object]

2. Converging ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Convergent boundaries Oceanic -Continental Oceanic-Oceanic Continental-Continental

3. Transform boundaries ,[object Object],[object Object]

Continental Drift Animation based on paleomaps from University of Texas Arlington http://www.ucmp.berkeley.edu/geology/anim1.html

Plate tectonics: predicting the future

Plate tectonics in the future: 50 my ,[object Object],[object Object],[object Object],[object Object],[object Object]

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