Geology Of Southern Victoria Land Antarctica

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 that describes the geology of the largest ice-free area in Antarctica. It covers 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). This map replaces a 1:250 000 map published in 1962.

Key features include:

• Geological information obtained from published and unpublished mapping by researchers from GNS Science, New Zealand universities, and the United States Antarctic Program.
• An illustrated text summarising the geology and landforms of the area, as well as previous geological exploration.
• An appendix with a lexicon of adopted stratigraphic names, unit codes, and descriptions.
• All geological data stored in a Geographic Information System, available in digital format.

Geological Highlights

The region is crossed by a major rift basin, with its uplifted shoulder forming the Transantarctic Mountains escarpment. Key geological features include:

• Large stratovolcanoes on Ross Island and the nearby mainland.
• Neoproterozoic and Paleozoic granitoids, and their host rocks, overlain by a thick sequence of Devonian-Triassic sedimentary rocks.
• Jurassic dolerite sills, Eocene to Holocene deposits in the Dry Valleys, and beneath the Ross Sea.
• A record of ice sheet and glacier fluctuations preserved in Miocene and later volcanic products.

Detailed Mapping

The map differentiates:

• Neoproterozoic Skelton Group: Metasedimentary rocks of greenschist to amphibolite facies.
• Granite Harbour Intrusive Complex: Late Proterozoic to early Paleozoic granitic plutons classified into four petrogenetic suites.
• Beacon Supergroup: Sedimentary rocks including the Devonian Taylor Group and the Permian to Triassic Victoria Group, further divided into 12 formations.
• Jurassic Ferrar Group: Dolerite sills and dikes intruding both basement and Beacon Supergroup rocks, along with the extrusive Mawson Formation and Kirkpatrick Basalt.
• Cenozoic volcanic rocks: McMurdo Volcanic Group of Mt Erebus/Ross Island and the southern Ross Sea region.

Additional Features

• Structural features of the Victoria Land Basin depicted on the cross-section.
• Miocene-Holocene glacial deposits (tills and drift), lacustrine, coastal, and slope deposits differentiated based on lithology, weathering, geomorphology, and limited dating.

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