Petrogenesis and Geochronology of the adakitic granites from Cape Hinode, East Antarctica

Abstract

The Cape Hinode in East Antarctica is mainly consists of tonalite, which is adakitic rocks. Granites are small amount of this area, and also similar to high SiO₂ adakite. The zircon U-Pb ages of granites are 1081±25 Ma~1026±23 Ma. Granites has low MgO, Cr and Ni contents, it seems that there are no reaction with the mantle. In addition, granites coincide with the composition range of TTG (>3.5 Ga). These evidence suggests that melting of young and hot slab in shallow subduction zone. It becomes a key to elucidate the tectonics about 1000 Ma.