Petrology and geochemistry of a megacrystic quartz monzonite, the Bodocó pluton, northeastern Brazil

Abstract

The coarse-grained Bodoco pluton is characterized by tabular megacrysts of K-feldspar in a matrix of plagioclase, hornblende, biotite, titanite, and quartz. The pluton is reversely zoned from a partly granitic and granodioritic margin to a voluminous quartz monzonitic (QMZ) core. Within the pluton, elongated km-wide zones of deformed, foliated megacrystic QMZ are associated with synplutonic dikes of dark gray monzonite and monzodiorite. Limited exposures of a topographically high region of the pluton have a hybridized texture in which felsic and mafic compositions are complexly intermingled.