Petrology and Tectonic Evolution of the Bowers Supergroup Northern Victoria Land, Antarctica
The Bowers Supergroup of northern Victoria Land, Antarctica is at least 6.5 km thick and consists of Solidarity, Molar, and Glasgow Formations of the Middle Cambrian Sledgers Group; Middle to late Cambrian Mariner Group; and Middle Ordovician Leap Year Group. The Solidarity Formation is at least 0.4...
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| Format: | Text |
| Language: | English |
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Western CEDAR
1987
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| Online Access: | https://cedar.wwu.edu/wwuet/740 https://cedar.wwu.edu/cgi/viewcontent.cgi?article=1762&context=wwuet |
| Summary: | The Bowers Supergroup of northern Victoria Land, Antarctica is at least 6.5 km thick and consists of Solidarity, Molar, and Glasgow Formations of the Middle Cambrian Sledgers Group; Middle to late Cambrian Mariner Group; and Middle Ordovician Leap Year Group. The Solidarity Formation is at least 0.4 km thick and consists of submarine tholeiites. The Molar Formation is up to 2.7 km thick and consists of slope-facies turbidites in its southwesternmost extent and shelf-facies sediments in its northeasternmost extent. Sediment provenance was the Glasgow Formation and a continental landmass lying northeast of the southwestern sloping Bowers basin. The Glasgow Formation is up to 2.7 km thick and consists of tholeiitic and calc-alkaline basalts to rhyolites erupted along a magmatic arc probably related to eastward subduction. The Mariner Group is a regressive marine sequence deposited during tectonic quiescence. The Leap Year Group rests unconformably on the Mariner and Sledgers Groups and consists of up to 2.5 km of molasse derived in part from the Granite Harbour Intrusives. The Bowers Supergroup was folded about N30ºW axes, metamorphosed to the prehnite-pumpellyite facies, then tectonically juxtaposed by strike slip faults between the Wilson and Robertson Bay terranes. Deposition of the Leap Year Group, folding, metamorphism, and faulting occurred between 480 to 425 Ma and were the results of collision between the Wilson and Bowers terranes representing the Ross Orogeny in northern Victoria Land. Between 420 and 384 Ma, refolding about N60ºE axes, normal faulting, and the emplacement of the Admiralty Intrusives occurred during the Borchgrevink Event by which time the terranes may have become stitched. The allochthonous nature of the rocks of the Bowers Supergroup may preclude their correlation with those of the Dundas Trough in Tasmanis. |
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