Background (PJB)

Two of the outstanding problems in Antarctic earth science are the early history of the East Antarctic Ice Sheet and the history of the Transantarctic Mountains, and they may well be linked. The GLOMAR CHALLENGER made the first major breakthrough in 1973 by recovering cores from the centre of the Rose Sea showing that ice rafting began there 25 m.y. ago and has been going on ever since (Hayes et al., 1975), but whether the floating ice came from East or West Antarctica is still debated. The cores contained little information about the history of the Transantarctic Mountains because the holes were too far offshore, and there is unlikely to be much further information from on land, for no dateable sequences from the key time period (50-10 m.y.) are known to crop out on land in the McMurdo Sound region. The glacial history and the uplift of the mountains are likely to be best recorded in the thick sedimentary sequence seen in seismic profiles along the Transantarctic Mountain Front (Northey et al., 1975). This sequence can be sampled only by drilling.

The first attempt to core this sequence (DVDP15) reached 65 m sub-bottom before sea ice conditions terminated drilling (Barrett et al., 1976). The second attempt, which is described here, was much more successful, though drilling was again terminated by sea ice conditions before the target depth was reached. Further background to the drilling can be found in Barrett (1979) and in the Scientific Operations Handbook (Barrett s Waghorn, 1979). Personnel for the operation are listed in Table 1.