L07_18_Sept_Petrology

Would melt this rock in now paraally melted conanental

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Unformatted text preview: nd it wasn’t unAl several 10’s or 100’s of million years aler the Earth formed that other rocks appeared More ‘evolved’ rocks such as diorite and granite cannot be formed by parAal melAng of mantle rocks. They form by parAal melAng of basalts and other ‘precursor’ rocks, including Si- and Al- rich sediments. In general, we can think of basalt- like rocks and their consAtuent minerals as precursor rocks (minerals) from most other rocks and minerals are derived. So, how do we get from basalt to some evolved rock like granite? MelAng and igneous rock formaAon at subducAon zones melAng is occurs under a complex interplay of increasing temperature (promoAng melAng), increasing pressure (hampering melAng), and presence of water (promoAng melAng). P- T phase diagrams...
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This document was uploaded on 03/26/2014 for the course GEC AS.270.103 at Johns Hopkins.

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