The Marine Record of the East Antarctic Ice Sheet

Due to the nearly complete ice coverage of the Antarctic continent, a record of past Antarctic climate lies in the layers of sediments eroded over million years from the continent and deposited in sedimentary basins around its margin and in the Southern Ocean.

During the past ca. 20 years, nine ODP legs have significantly advanced our understanding of the Cenozoic tectonics and palaeoenvironments of the Antarctic region. These legs include Leg 113 in the Weddell Sea (Barker et al., 1988, 1990), Leg 114 in the sub-Antarctic South Atlantic (Ciesielski et al., 1988, 1991), Leg 119 in Prydz Bay and on Kerguelen Plateau (Barron et al., 1989, 1991), Leg 120 on Kerguelen Plateau (Schlich et al.. 1989; Wise et al., 1992), Leg 177 in the southeast Atlantic sector of the Southern Ocean (Gersonde et al., 1999, 2003), Leg 178 on the Antarctic Peninsula (Barker et al., 2002), Leg 181 (Carter et al., 2000), Leg 188 in Prydz Bay (O'Brien et al., 2001; Cooper et al., 2004) and Leg 189 in the Tasmanian region (Exon et al., 2001, 2004).

The pioneer of Antarctic drilling was the DSDP in 1973 (Hayes et al., 1975). Following that, four distinct phases of drilling have taken place in the Ross Sea region, in sedimentary basins under the direct influence of East Antarctica, by rigs mounted on the fast-ice that rings the southern part of the Ross Sea just north of the Ross Ice Shelf (see Chapter 3 for further details). These include the Dry Valley Drilling Project (DVDP) in 1970-1975 (McGinnis, 1981), the McMurdo Sound Sediment and Tectonic Studies (MSSTS) in 1979 (Barrett, 1986), the Cenozoic Investigations in the Western

Ross Sea (CIROS) in 1984 and 1986 (Barrett, 1989; Barrett et al., 1992) and the multinational CRP in 1997-1999 (Cape Roberts Science Team, 1998, 1999, 2000; Hambrey et al., 1998; Barrett et al., 2000, 2001). These efforts are continuing through ANDRILL (Antarctic geological drilling) programme, which demonstrated ability to recover high quality marine and glacimarine sedimentary drill cores from high latitude ice-covered areas (Naish et al.. 2007; Florindo et al., 2008; Harwood et al., 2008).

To date, in spite of these efforts, important questions and problems remain unresolved and are the subject of a considerable debate within the scientific community. Among these are the causes of the mid-Miocene cooling event at around 14 Ma, and the warming-cooling climatic phases of the Pliocene.

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