Cox, S.C.; Turnbull, I.M.; Isaac, M.J.; Townsend, D.B.; Smith Lyttle, B. (comps) 2012 Geology of southern Victoria Land Antarctica. Lower Hutt: GNS Science. Institute of Geological & Nuclear Sciences 1:250,000 geological map 22 135 p. + 1 folded map
Abstract: The “Geology of southern Victoria Land” is a 1:250 000 map and monograph describing the geology of the largest ice-free area in Antarctica. Covering the region between the Fry Glacier in the north and the Skelton Glacier in the south (~76°30’S–78°45’S), and from the Polar Plateau to Ross Island (158°E–170°E), the map replaces a 1:250 000 map published in 1962. Geological information has been obtained from published and unpublished mapping by researchers from GNS Science, New Zealand universities and the United States Antarctic Program. The accompanying illustrated text summarises the geology and landforms of the area, as well as previous geological exploration. An appendix includes a lexicon of adopted stratigraphic names, unit codes and descriptions. All geological data are held in a Geographic Information System, and are available in digital format. The region is crossed by a major rift basin, its uplifted shoulder forming the Transantarctic Mountains escarpment. Associated with this rift are large stratovolcanoes on Ross Island and on the mainland nearby. In the Transantarctic Mountains, Neoproterozoic and Paleozoic granitoids and their host rocks are overlain by a thick sequence of Devonian-Triassic sedimentary rocks, and intruded by Jurassic dolerite sills. Eocene to Holocene deposits in the Dry Valleys and beneath the Ross Sea, including the products of Miocene and later volcanism, preserve a record of ice sheet and glacier fluctuations. The map differentiates Neoproterozoic Skelton Group, comprising metasedimentary rocks of greenschist to amphibolite facies, from late Proterozoic to early Paleozoic granitic plutons of the Granite Harbour Intrusive Complex, which are classified into four petrogenetic suites. These basement rocks, truncated by the Kukri Erosion Surface, have been overlain by sedimentary rocks of the Beacon Supergroup which includes the Devonian Taylor Group and the Permian to Triassic Victoria Group, together differentiated into 12 constituent formations. Jurassic Ferrar Group dolerite sills and dikes intrude both basement and Beacon Supergroup rocks. The extrusive Mawson Formation and Kirkpatrick Basalt of the Ferrar Group are exposed locally. The map shows Cenozoic volcanic rocks (McMurdo Volcanic Group) of Mt Erebus/Ross Island and the southern Ross Sea region in the context of the Transantarctic Mountains and Dry Valleys. Structural features of the intervening offshore Victoria Land Basin are depicted on the cross-section. Miocene-Holocene glacial deposits (tills and drift), lacustrine, coastal, and slope deposits have been differentiated based on lithology content, weathering, geomorphological criteria and the limited dating available. (auth)
