Monday, November 9, 2009

Pages 194-197, Questions 1-3

1) Water in the subducted rock is released into the athenosphere, the water lowers the melting point, leading to the formation of magma. When the subducting plate melts, the magma gets less dense and rises.
2) At a hot spot, the magma is straight from the core, it pushed upward through the crust. It doesn't matter what kind of plate is at the boundary, because it rises in the middle of the plate. At the subduction boundary, the process of making magma is much different and the volcanoes at the subduction boundary have different magma than at hot spots.
3) At a divergent boundary, the plates split apart and magma is formed by the combination of low pressure and high temperature, then the magma is pushed up through the crust, and new crust is formed by the cooling magma.

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