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Petrology and geochemistry of the East Antarctic Craton: insights for pre-basin geology along the Transantarctic Mountains rift shoulder

Abstract

The known geology of Antarctica is based on limited samples from outcrops projecting through ice as mountain ranges and isolated nunataks. Thus thick sedimentary basins indicated by seismic reflection and aeromagnetic surveys are underrepresented and largely inaccessible. One approach to elucidate basin evolution at the margin of East Antarctica is to investigate the prebasin geology of the underlying bedrock. The Nimrod Complex, in the central Transantarctic Mountains, represents the only exposed basement rocks for the East Antarctic Craton. Further, the Nimrod Complex strata have been linked to early Earth reconstructions placing Gondwana (i.e., East Antarctica) adjacent to Laurentia (i.e., modern day southwestern United States). This pre-basin geology of the rift shoulder can provide insight on the structural geology and tectonic history of the resources and structures hidden below the ice sheet. Additionally, oxygen isotopes from these crystalline basement rocks can record fluid transport during earlier collisional tectonics when the East Antarctic margin represented a long-lived subduction zone. Thus, the East Antarctic margin affords a unique opportunity to better constrain predictions for mineral resources and early Earth global tectonics for a poorly understood region.