Petrology of an epizonal gabbroic suite: the Batow pluton, Yamizo Mountains, Central Japan

摘要: The Batow pluton, an epizonal gabbroic body, Central Japan, was studied to delineate its geologic, petrographic and geochemical characteristics. Though the pluton is small, it exhibits a wide compositional range from melagabbro granodiorite varies 42.8 62.7 wt.% SiO2. rocks have similar features calc-alkaline, magnetite-series I-type plutonic are characterized by high abundances of lithophile elements, comparable those in shoshonite rock association. Crystallization path calculations observations suggest that variation brought mainly amphibole- plagioclase-dominated fractionation magma with minor clinopyroxene, biotite potash feldspar. This occurred at comparatively shallow crustal level, deeper than 2kb, before upward migration. granitic abundance amphibole (up 39%) scarcity (less 4%) were formed higher P H2O lower temperature early-crystallized gabbros. close association clinopyroxene- biotite-rich gabbro, whose clinopyroxene plagioclase often show reverse zoning Mg/(Mg+Fe*) ratio An content, amphibole-rich gabbro suggests had increased rapidly during crystallization melt. intrusion H2O-saturated granodioritic melt may caused rapid increase H2O.