DIORITE AND GABBRO OF THE DROMEDARY MAFIC COMPLEX, SOUTH VICTORIA LAND, ANTARCTICA

The syntectonic Dromedary mafic complex is a well-preserved mafic body which was emplaced into Koettlitz Group metasediments during widespre ad late Proterozoic-Paleozoic granitoid plutonism, metamorphism, and d eformation in South Victoria Land, Antarctica. The 4 x 9 km pluton is reversely zoned. It consists of a core of calc-alkaline cumulate and n oncumulate gabbros-comprising gabbro, olivine gabbro, anorthosite, nor ite, and pyroxenite-surrounded by an outer margin of homogeneous pyrox ene-bearing diorite. All rocks have undergone varying degrees of metam orphic reconstitution. The resulting assemblages are strongly controll ed by original rock composition. Field relationships and geochemical d ata suggest that the diorite and gabbro are coeval and cogenetic. The Dromedary mafic complex has geochemical signatures distinct from most other nearby dioritic bodies. It does, however, plot as an extension o f syntectonic granitoids from the Dry Valley region.