Aurora Subglacial Basin

Aurora Subglacial Basin. It is a vast, topographically low region lying beneath the East Antarctic Ice Sheet, centered inland from the Shackleton Ice Shelf and Totten Glacier. This deep sedimentary basin is one of the most significant and potentially unstable subglacial features in Antarctica, containing ice grounded well below sea level. Its dynamics are a critical focus for research into ice sheet stability and future global sea level rise.

Geography and location

The Aurora Subglacial Basin is situated in the interior of East Antarctica, extending roughly from the Gamburtsev Subglacial Mountains in the west towards the Wilkes Land coast. It underlies a major portion of the Aurora Subglacial Trench and drains towards the Sabrina Coast and the Vincennes Bay region. The basin's topography is bordered by the elevated bedrock of the Transantarctic Mountains to the south and the Dome A region of the Antarctic Plateau. Its extensive subglacial channels connect it to major outlet glaciers like the Totten Glacier and the Denman Glacier, which serve as primary conduits for ice discharge into the Southern Ocean.

Geology and formation

The basin is interpreted as a major rift basin or a failed continental rift system, likely initiated during the Mesozoic era as Gondwana began to break apart. Its structure is filled with several kilometers of sedimentary strata, overlain by sequences of Cenozoic glacial deposits. Geophysical surveys, including those by the British Antarctic Survey and the Antarctic Gamburtsev Province (AGAP) project, suggest the basement rock is analogous to the Ferrar Large Igneous Province. The formation processes are linked to tectonic extension between the East Antarctic Craton and the West Antarctic Rift System, with subsequent subsidence and sediment infill from ancient river systems prior to the onset of full continental glaciation.

Subglacial hydrology

The basin contains an extensive and dynamic network of subglacial lakes and water systems, including the large Lake Vostok to its southwest and the Recovery Lakes to its north. Water flow is governed by variations in geothermal heat flux and ice pressure melting point, facilitating widespread basal lubrication. Major water pathways converge towards the Totten Glacier grounding line, influencing its flow velocity. The presence of saturated sediments and deformable till layers, studied by projects like ICECAP (International Collaborative Exploration of the Cryosphere through Airborne Profiling), suggests a complex hydrological system that can rapidly transmit water pressure changes, potentially destabilizing the overlying ice.

Exploration and research

Initial hints of the basin's existence came from early seismic surveys conducted by the Soviet Antarctic Expedition and the United States Antarctic Program in the 1960s. Its full extent was later mapped through extensive airborne radio-echo sounding campaigns, notably by the British Antarctic Survey and the University of Texas at Austin's Institute for Geophysics. Major international projects like the International Polar Year and ICECAP (International Collaborative Exploration of the Cryosphere through Airborne Profiling) have deployed advanced ice-penetrating radar and gravimetry instruments. Ongoing monitoring is conducted by agencies such as NASA's Operation IceBridge and the European Space Agency's CryoSat satellite.

Significance and implications

The Aurora Subglacial Basin is considered a primary candidate for initiating rapid ice sheet retreat in East Antarctica due to its deep, marine-based topography and extensive subglacial water network. Its stability is a major uncertainty in projections by the Intergovernmental Panel on Climate Change. If the Totten Glacier grounding line retreats into the basin, it could trigger a self-sustaining marine ice sheet instability, potentially committing the world to several meters of global sea level rise over centuries. Research here directly informs international climate policy and mitigation strategies discussed within frameworks like the United Nations Framework Convention on Climate Change.

Category:Subglacial basins of Antarctica Category:Geography of East Antarctica Category:Geology of Antarctica