Geological mapping 1:50,000 in the Thundergut area (Olympus and Asgard Range, Taylor Glacier), South Victoria Land

1:50,000 geological mapping of the Thundergut area was conducted covering an area from the western tip of the Kukri Hills, as far west as the Solitary Rocks, Friis Hills and Asgard Ranges and as far north as the Wright Valley, with the northern limits determined by the time available. Mapping involved an examination of all rock types encountered in the field. Basement studies will attempt to unravel the structural development and relationship between Koettlitz Group metasediments and associated, interrelated orthogneisses. Mapping of granitoids intruding meta-sediments and orthogneisses concentrated on defining individual intrusive bodies and deciphering an intrusive sequence. Samples retrieved during the fieldwork were analysed and the validity and consistency of these two suites were tested over a larger area as part of ongoing labwork after initial map production. In addition, extensive mapping was completed on the southern wall of the Wright Valley. Three specific problems were targeted during this work. Initial mapping found the presence of two granitoid plutions above the lower dolerite sill but the contact relations at this altitude were obscured by the Heimdall Glacier and moraine deposits. Mapping lower on the southern wall of the Wright Valley aimed at observing the contact of these two plutons and determining their relative ages. The second aim of the mapping was to tie the Bull Pass drillsite core into the intrusive sequence. This would allow samples of this core to be used for geochemical and dating analysis when funding permits. The third aim was to try to tie the U-Pb date from an Olympus Granite Gneiss sample near the Connor Glacier into the intrusive sequences and gain further absolute age control on geologic events in Southern Victoria Land.