Radiometric Ages of Pre-Mesozoic Rocks from Northern Victoria Land, Antarctica
- Garry D. Mckenzie
Published Online: 21 MAR 2013
Copyright 1987 by the American Geophysical Union.
Gondwana Six: Structure, Tectonics, and Geophysics
How to Cite
Kreuzer, H., HöHndorf, A., Lenz, H., MüLler, P. and Vetter, U. (1987) Radiometric Ages of Pre-Mesozoic Rocks from Northern Victoria Land, Antarctica, in Gondwana Six: Structure, Tectonics, and Geophysics (ed G. D. Mckenzie), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM040p0031
- Published Online: 21 MAR 2013
- Published Print: 1 JAN 1987
Print ISBN: 9780875900643
Online ISBN: 9781118664483
Northern Victoria Land forms the Pacific end of the Transantarctic Mountains. Three major thrust-bounded terranes are distinguished. The Wilson Terrane (WT), with low- to high-grade partly polyphase metamorphics, is in the west; the Robertson Bay Terrane (RBT), with low-grade metaturbidites, is in the east; and squeezed between these two, with indications of a suture zone at the margin of the western terrane, is a third, the narrow Bowers Terrane (BT), with a low-grade metamorphic regressive Cambrian sequence of volcanics and marine to fluviatile sediments. All three terranes were affected by early Ordovician events. Models for the relationships of the three terranes have to consider the following observations. Rb-Sr whole-rock isochron ages of about 600 and 530 Ma are suggested for the WT as well as for the northern margin of the RBT. The Ordovician Granite Harbour Intrusives are restricted to the WT, but similar Ordovician ages of 500 to 460 Ma are determined for all three terranes on micas or schists and slates. Hence, a common history is possible for all three terranes since the Ordovician. The atectonic Devonian to Carboniferous Admiralty Intrusives (370–350 Ma) intrude mainly the eastern terrane but probably cut the bounding thrust zones of the terranes. They show a southwestward decreasing crustal contamination and have characteristics of postcollision I-type granitoids, allowing the speculation of a juxtaposition of the three terranes in the Devonian. Permian Beacon sediments and Jurassic Ferrar Dolerites in the western, the Bowers, and the Wilson terranes indicate that the three terranes were thrust together at least in the late Paleozoic.