Abstract:
ANDRILL (ANtarctic DRILLing project) is a multinational (Germany, Italy, New Zealand and USA) initiative to investigate the climate and tectonic history of Antarctica by recovering deep sediment cores from the sedimentary basins beneath the floating McMurdo/Ross Ice Shelf (RIS). The response of Antarctic ice sheets to projected greenhouse warming of up to 5.8°C by the end of the century is
... unknown and models on which predictions are based need to be constrained by geological data of the ancient ice sheets during past times when earth was known to be warmer than it is today. Future stability of the RIS, which is coupled to the behaviour of the West Antarctic Ice Sheet (WAIS), is of wide interest in the context of current global warming projections. The RIS is considered stable but it is being undernourished with ice from West Antarctica as its ice stream feeders are slowing down. A continued reduction in discharge could trigger retreat and/or widespread break up. Collapse of the RIS could affect global climate in a number of ways including altering the production of salty bottom water around Antarctica thus altering the global thermohaline circulation system and global climate, altering the albedo and causing regional warming (ice-albedo feedback) and the exchange of heat and water vapour between the ocean and the atmosphere could lead to accelaerated loss and eventual collapse of the marine based WAIS, raising sea level by 5-6m. The goal of ANDRILL was to gain an understanding of the past behaviour of the Antarctic Ice Sheets (east and west) and the McMurdo/Ross Ice Shelf and their role on global climate change. A team of over 200 scientists, technicians, educators and support staff from all countries collaborated over two main seasons of drilling and four prior seasons of drill site investigations to recover sediment core below the sea floor that represent a nearly unbroken geological history of Antarctic ice shelf/sheet advance and retreat during the last 5 million years. Drilling operated during the 2006-2007 (McMurdo Ice Shelf) and 2007-2008 (Ross Ice Shelf) season, recovering 1284.87 m and 1138.54 m of sediment cores each season respectively (both with 98% recovery), a record depth of sub-bottom penetration in the Antarctic region and the first drilling rig to operate through a floating ice shelf. The ice core was analysed to determine how the Antarctic ice sheets behaved during periods of global warmth greater than the present day and climate and ice sheet models were created to extend the results to provide guidance regarding potential response by the West Antarctic Ice Sheet and Ross Ice Shelf to future scenarios of global warming. All of the cores were sent to Florida State University, Tallahassee, USA. 
