Geological mapping 1:50,000 was conducted in South Victoria Land to draw together previous mapping works to produce a map of the geology between the Asgaard and Clare Ranges. Previous work includes the western part of the Asgaard and Olympus Ranges (1982/83) and the Beacon Supergroup at Mt Bastion, Skew Peak and Robinson Peak in the north (1984/85) with adjoining published sheets of the Thundergut ... area in the south (1991) and St Johns Range in the east. Six major rock groups were mapped including the Koettlitz Group, Granite harbour Intrusives, Victoria Group, Taylor Group, Ferrar Group and Neogene deposits and surficial features. The oldest is the Koettlitz Group metasediment (Precambrian) which crops out in the eastern part of the map area. In the same area, several granitoid plutons and dike swarms (Granite Harbour Intrusives, early Ordovician) intrude the Koettlitz Group and each other. Beacon Supergroup sediments of the Taylor Group (Devonian) are present in the east and south, whereas the Victoria Group (upper Carboniferous to Triassic) occurs in the west and north of the mapped area. Ferrar Group dolerite sills (Jurassic) intrude all the above rock units and form the bulk of the Clare Range. Some possible extrusive rocks of the same group were seen near Mt Dearborn and Vishniac Peak. The youngest lithologies mapped are glacial and surficial deposits, which occur throughout the area but particularly in the valley floors. Field work was supplemented by geochemical, petrological and paleontological work in New Zealand.