Location of South Georgia and potential impact on early Pacific-Atlantic through flow

One of the most significant Cenozoic reconfigurations of global ocean circulation involved the initiation of Pacific to Atlantic exchange that led to the isolation of Antarctica by the Antarctica Circumpolar Current though the separation of South America and Antarctica and the opening of the Scotia Sea and Drake Passage. Whether significant Pacific to Atlantic through-flow was possible in the early Cenozoic has remained unclear because it is not certain where continental fragments such as South Georgia, a potential barrier, were located before seafloor spreading created the Scotia Sea. Establishing where South Georgia was located is also critical to reconstructing the Scotia arc and understanding its evolution. Detrital zircon U-Pb geochronology and apatite thermochronometry are used to constrain the pre-drift location of South Georgia. Data from Cretaceous turbidites exposed on South Georgia are consistent with a former connection to the Rocas Verdes back-arc basin giving support to models that have argued for a pre- tectonic translation location southeast of Tierra del Fuego. Following an early phase of rock uplift, thermal history models of the apatite chronometry data indicate that the South Georgia continental fragment underwent burial related heating and was therefore not a significant topographic feature until it emerged c. 10-7 Ma coeval with the cessation of spreading at the West Scotia Ridge and collision between the South Georgia continental block and the Northeast Georgia Rise.