Petrological evolution of basement granitoids Southern Victoria Land, Antarctica

Several workers have studied the basement and other granitoids in the Dry Valleys, without a detailed petrographical and chemical study of these rocks. This study was aimed at elucidating the evolution of basement granitoids observed in the Taylor Valley and Ferrar Glacier region with fieldwork involving a systematic covering of ground within walking distance of each camp. At each new outcrop visited, field sketches and photographs were taken, particularly of new intrusions and contact relationships. At the Taylor Valley, three major granitoids were mapped and the sharp intrusive contacts between tonalite and megocrystic granite were observed. At the Ferrar Glacier, two major granitoid lithologies were mapped across the other side of the Ferrar glacier at Cathedral Rocks. From both sites, similar granitoids were correlated with one another clarifying the intrusive sequence and providing petrogenic hypothesis for the origin of these granitoids with thin section and chemical analysis, whole rock analysis, petrographic work, electron microprobe analysis of minerals and all samples undergoing chemical, modal and microstructural examination. Microgranitoid encloves were examined in detail for differences in conditions of formation from host granitoids.