GEOL 101 Lecture Notes - Lecture 3: East African Rift, Continental Crust, Oceanic Crust
18 Oct 2016
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Earth"s major plates: seven major lithospheric plates (what are they?) Plate tectonics: most plates contain both land and ocean crust, plates are constantly moving, and in turn changing size/shape, plates move at a slow, continuous rate. About 5cm (2 inches) per year: the ocean crust is cooled mantle rock is more dense and sinks back into the interior this is what causes the movement of the plates across the surface of the earth. Constantly moving in a convection system that causes plate movement. Hard to determine the exact flow/movement/system because there is little data at such a great depth. Ocean crust is formed by cooled magma (basalt) (igneous) As the hotter rock rises in certain areas, islands/volcanoes are formed: the mantle. Plate tectonics: a constant cycle of movement of the plates, deals with the outer portion of the earth (upper mantle and crust, continental drift. Hypothesis first proposed by aflred wegener in 1915.
