Geological Position and Isotopic Age of Intrusive Charnockitic Rocks in the Jennings Promontory (Eastern Wall of the Amery Glacier, East Antarctica)

摘要

Intrusive hypersthene granitoids (charnockitic rocks) are widespread in the mountainous system bordering the Lambert Glacier with the world's largest outlet and Amery Ice Shelf continuing in East Antarctica. In the eastern margin of the Amery Ice Shelf, they constitute large bedrock outcrops in the Jennings Promontory (approximately 6 km~2) and Branstetter Rocks (approximately 0.7 km~2) and several outcrops approximately 9.5 km~2 in total in Gillock Island (Fig. 1). These outcrops of charnockitic rocks most likely characterize a relatively large massif, which extends in the northeasterly direction and occupies an area of at least 140 km~2 in size. This massif intrudes metamorphic granulitic rocks represented by the Reinbolt orthog-neiss and Larsemann paragneiss groups (Fig. 1).