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METAMORPHIC-LECTURE 4 - Coggle Diagram
METAMORPHIC-LECTURE 4
Wet melting
H2O dissolves in silicate melt, thus loweing the melting point
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If at high P all H2O is dissolved and melt segregates and leave its source, then there is reduction of flui P in the residue, thus causing fluid absence. If rocks keep heating up then there will be melt at high T through fluid--absent reactions. Result: H2O-undersat melt
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Migmatites
High grade, 2nd sill isograd
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Leucosome: pale lense, qtz+fsd
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Mesosome: schistose darker bands, AFM phases
Malnosomes: boudaries between leucosomes and mesosomes, concentration of AFM minerals. Reflect melting-related processes
Melt evidence: inclusions within grt (leucosomes) of kfs, palg, qtz
Dehydration melting
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No free H2O phase, involves only melt and minerals
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