ERS120H5 Lecture Notes - Lecture 14: Isostasy, Continental Crust, Accretionary Wedge
23 Oct 2017
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Document Summary
Basin and range province: small volumes of basaltic magma, not enough to melt the rocks aroud them, form accretionary prism, build up volcanoes, little bits of crust out in the ocean, island get scraped off oceanic plate. Convergent tectonics - terrane accretion: as subduction progresses, the island arc and continental crust resist being sunducted and are pulled together, pinching sediments between them. Thrust faults develop: the oceanic crust subducts and the island arc collides with the continental crust, causing sediments to be metamorphosed and further development of thrust faults. Subduced oceanic curst melts in the mantle and plutons rise along the subduction pathway: the island arc becomes sutured to the continental crust. Rising plutons become emplaced in the lower crust and drive additional metamorphism of sediments. Convergent tectonic continental collision: significant aerial extent, high elevation (3-5000+m, low- relief, thick crust (50-70km) The thickest block floats highest and sinks deepest.
