Abstract

Adjacent to magnetite concentrations, recrystallization of amphibolites to hornblende skarns involved enrichment of ferromagnesian silicates in Mg, release of Fe to form magnetite, and conversion of calcic plagioclase to sodic. Recrystallization controlled by pressure gradients toward shear zones is believed to have caused release of fluids that transported Ca, Al, Fe, Mn, Ti, Ba, Sr, V, Cr, and Zn out of the system. The same elements were probably removed from granitic gneisses, forming alaskites. Hornblende granite formed where these fluids were added.

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