This project is an aerogeophysical survey to explore unknown terrain in East Antarctica to answer questions of climate change and earth science. The methods include ice-penetrating radar, gravity, and magnetic measurements. The project?s main goal is to investigate the stability and migration of ice divides that guide flow of the East Antarctic ice sheet, the world?s largest. The project also maps ice accumulation over the last interglacial, identifies subglacial lakes, and characterizes the catchment basins of the very largest glacial basins, including Wilkes and Aurora. The outcomes contribute to ice sheet models relevant to understanding sea level rise in a warming world. The work will also help understand the regional geology. Buried beneath miles-thick ice, East Antarctica is virtually uncharacterized, but is considered a keystone for tectonic reconstructions and other geologic questions. The region also hosts subglacial lakes, whose geologic histories are unknown.
The broader impacts are extensive, and include societal relevance for understanding sea level rise, outreach in various forms, and education at the K12 through postdoctoral levels. The project contributes to the International Polar Year (2007-2009) by addressing key IPY themes on frontiers in polar exploration and climate change. It also includes extensive international collaboration with the United Kingdom, Australia, France and other nations; and offers explicit opportunities for early career scientists.
The East Antarctic Ice Sheet (EAIS) is one of the key features of the Cenozoic Earth, dominating the Antarctic continent and strongly influencing global climate, sea level, and oceanography. Until recently, little was known about large sections of the EAIS, a problem that the ICECAP project was designed to address as part of the International Polar Year. Key problems included understanding the origin and evolution of the EAIS, correctly determining the boundary conditions that will determine the EAIS fate, and establishing mapping out the potential climate archive of the ice sheet for deep ice coring. The region targeted was the Wilkes Land region south of Australia, home of several vast subglacial basins. An integrated aerogeophysical instrument suite (comprising ice penetrating radar, laser altimetry, airborne magnetics and gravimetry) that was developed over the late 1990‘s for the short range, deep field Twin Otter was migrated to a long range, ski equipped turbine DC-3 aircraft. The DC-3’s range allowed survey lines to penetrated the ice sheet for up to 1000 km from established Antarctic stations, with limited logistical impact. ICECAP was a truly international program that primarily operated from three stations - the US Antarctic Program’s McMurdo Station, the Australian Antarctic Program’s Casey Station, and the joint Italian-French Concordia Station that lies between them on Dome C. Aircraft costs were provided by the United Kingdom’s National Environmental Research Program and Australia’s ACE-CRC; GPS support was provided by UNAVCO and EarthScope, and gravimeter support by the National Geospatial Intelligence Agency and the British Antarctic Survey. ICECAP/IPY conducted four years of survey operations between 2008 and 2011. ICECAP was augmented in later seasons by NASA’s Operation Ice Bridge, and the Danish Technical University’s IceGrav program, providing access to the George V Coast, the Antarctic Pennisula, and Dronning Maud Land. Key science findings of ICECAP Important findings of ICECAP emerged from the first detailed mapping of the vast Aurora Subglacial Basin that lies south of Casey Station. We found that the margins of the basin were cut by a succession of vast subglacial fjords that ran orthogonal to current ice flow patterns. These fjords represented the margin of the ice sheet in epochs where much higher glacial erosion rates than currently exist in the EAIS prevailed, consistent with a smaller ice sheet forming in a ‘greenhouse’ world warmer that currently exists. These fjords form part of a vast subglacial river system that efficiently drains the ice sheet all the way back to the interior at Dome C. Some points along this system are delicately balanced locations where water can alternately flood out outlets spaced 1,000 km apart. For the first time, the dimensions of these rapidly changing outlet glaciers (Totten Glacier and Denman Glacier) were mapped out, showing them to be among the most significant glaciers in East Antarctica. Between the ice core sites at Dome C (extending to 800 thousand years) and the Russian ice core site at Vostok (to 400 thousand years), ICECAP radar data was used to construct a stratigraphy using layers in the ice extending 700 km between the two sites, which will be used to test the age models used for understanding the ice cores, and for finding likely sites for ice over 1 million years old. Broader Impacts of ICECAP ICECAP was operated in the field by a team of research scientists, technical staff, international collaborators and nine graduate students and early career postdocs. A majority of the students and postdocs had no experience in geosciences when first participating in this project, and are now pursuing careers in this area of STEM. ICECAP was featured in documentaries by Australian and Danish television networks and in the high profile 'Frozen Planet' documentary series by the BBC's Natural History division, and in a number of books describing IPY-era Antarctic exploration. ICECAP data has been used for targeting an new Australian ice coring effort to obtain a high resolution record from the Aurora Subglacial Basin, and a new cruise by the USAP’s MV Palmer to the mouth of Totten Glacier scheduled for February 2014. ICECAP is also a key contributor to the Bedmap2 and ADMAP magnetic compilations. An enormous amount of ICECAP data is being delivered to the community via the IceBridge data portal at NSIDC.
