New field and petrographic data about igneous rocks from Barnard Point, Livingston Island, Antarctica

Abstract

The Southeastern area of Livingston Island is built up by igneous rocks of the Eocene Barnard Point Pluton and related or younger dykes. Our new field and petrographic studies in the area show that the pluton consists of several main rock varieties namely gabbro, gabbrodiorite, granodiorite and granites, whose relationships evidences magma mixing processes. The internal parts of the former chamber contain levels enriched in mafic microgranular enclaves forming pronounced magmatic foliation, which towards western contact of the pluton transits to a subvertical N-S trending solid-state foliation and both parallelize the main foliation of the metamorphic host rocks. The latter evidences for a room creation and magma emplacement in tectonically active setting.