The Center Pond pluton: The restite of the story (phase separation and melt evolution in granitoid genesis)

The Center Pond pluton is a calc-alkaline post-tectonic Acadian body intruding chlorite grade Silurian metasediments of E-central Maine. Mapping and petrographic work reveal that the pluton contains 5 igneous rock types; quartz diorite, hornblende-biotite granodiorite, biotite granite, porphyritic granite, and aplitic granite. The linearity of major and trace element trends and Rb-Sr isotope systematics indicate that partial melting and unmixing of a single mafic or intermediate metaigneous rock to restite (residual phases in equilibrium with the melting event at depth) and near-eutectic minimum melt may account for much of the observed geochemical variation within the Center Pond pluton. Major and trace element trends rule out fractional crystallization as a model for Center Pond. -from Authors