GEOS 1004 Lecture Notes - Lecture 6: Basalt, Divergent Boundary, Mafic
Document Summary
Magma generation is fundamentally a product of earth"s internal heat a. b. Heat from deep in earth"s interior moved outward towards the surface, providing a driver for melting and magma generation. Granite magma body which cooled deep in the earth; now exposed by miles of erosion. Wet melting of upper mantle above subducting slab. Melting occurs when temperature is high enough to cause vibration that breaks bonds between ions. Melt- is a disordered version of parent material i. Lowered temperature (cooling) allows ordered bonds to form to produce minerals. At depths well below the earth"s surface - intrusive or plutonic rocks. Or: at earth"s surface after eruption - extrusive or volcanic rocks. It makes large crystals surrounded by a fine-grained matrix iii. Fast cooling produces a very fine grained texture, with few visible mineral grains. No time provided for ions to organize into crystal structures. Wet melting- introduction of water at subduction zones i.
