Permian-Triassic Basin History of Southern Victoria Land & the Darwin Mountains

Project Description
This is a collaborative sedimentology, palynology, and paleomagnetic study of Permian and Lower Triassic strata in southern Victoria Land (SVL) and the Darwin Mountains (DM), Antarctica. Results will help constrain the paleo-environmental, tectonic, palynostratigraphic, and paleogeographic histories of southern Pangea and provide a unique polar view of the world during an icehouse to greenhouse transition.

Upper Paleozoic and Lower Mesozoic rocks in SVL and DM were deposited during Gondwanaland's drift across the south pole, and during a transition from Icehouse to Greenhouse conditions following the demise of late Paleozoic glaciation. Based on present plate reconstructions, SVL and DM were located higher than 75 S from 320 to 210 Ma. Therefore, SVL and DM strata may provide an unusual high latitude view of the late Paleozoic and early Mesozoic world. However, Permian and Triassic mean pole positions for Gondwanaland are not well constrained and have large errors associated with them. We will attempt to recover Permian and Triassic paleomagnetic signatures from petrified wood, silicified peat, and coal, all of which were cemented during early diagenesis (preliminary results indicate stable remanent magnetizations).

Despite a proposed high latitude position, SVL and DM sedimentary successions record a change from Lower Permian glacigenic deposits, to Permian fluvial coal measures, to Lower Triassic non-carbonaceous fluvial deposits, and finally to Middle and Upper Triassic fluvial coal measures. Present climatic simulations suggest seasonal climatic extremes within Pangea's polar interior. Discrepancies between the geological evidence and the climate simulations need to be resolved and may be magnified by incomplete understanding of the influence of paleotopography, large lakes, and river systems at the time of deposition, as well as by incomplete documentation of paleo-environmental conditions.

The assemblage and drift of Pangea resulted in heightened orogenic activity and associated development of numerous depositional basins. One of the largest basins was the 10,000+ km long "Gondwanide foredeep" that extended across southern South America, South Africa, the Falkland Islands, Antarctica, and Australia. Diachronous tectonism and an inversion tectonics are believed to have occurred along this margin. Antarctica's centralized location between South Africa and Australia, make SVL and DM key areas for testing these hypotheses.

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