The History
of the Cape Roberts Project
Summary:
The Cape Roberts Project is a cooperative venture between scientists, administrators and Antarctic support personnel from 7 countries - Australia, Britain, Germany, Italy, Netherlands, New Zealand and the United States of America. It was set up to investigate the early history of the East Antarctic ice sheet and the West Antarctic Rift System by coring sedimentary strata at 77º south, at the edge of the present ice sheet and close to the Transantarctic Mountains. The project was developed in 1993 from earlier drilling on the fast ice in McMurdo Sound.
Drilling strata on the Antarctic continent began with Leg 28 of the Deep Sea Drilling Project (1972-73), when the
Glomar Challenger (pictured right) sailed into the Ross Sea to core 4 holes on the Ross continental shelf
(DSDP 270-273). These were cored to depths of between 200 and 440 mbsf, and recovery ranging from 7%
(DSDP 271) to 60% (DSDP 270). The cores were of marine glacial sediment, indicating extensive ice-rafting, implying glaciers calving ice at sea level at least 25 million years ago (results in DSDPLeg 28, Initial Report, 1975). This suggested that the continent had acquired an ice cover much earlier than in the last 2 million years, the common belief of the times.
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The results of the Deep Sea Drilling Project (above) were extended by the Dry Valley Drilling Project (1972-1975), an international project involving USA, New Zealand and Japan. The project cored over 300m of fjord deposits in Lower Taylor Valley dating back to around 6 million years ago (DVDP-8 to 11). The final hole (DVDP-15) was the first to be drilled from the fast sea ice into the floor of McMurdo Sound. That effort penetrated only 65m into the seafloor before cracks in the ice halted drilling. Drilling was continued through the NZ Antarctic Research Program in 1979 with MSSTS 1, which cored to 226 mbsf to glacial marine sandstone and mudstone also around 25 million years old (results in NZ DSIR Bulletin, 239, 1986).
The success of
MSSTS-1, and further seismic surveys in McMurdo Sound, led to the CIROS project,
also carried out by the NZ Antarctic Research Programme. Four holes were planned
– two off the mouth of the Ferrar Glacier (one nearshore and the other
offshore, on the seaward side of the rift margin), and the other two off Cape
Roberts, based on seismic data acquired in 1980 showing a spectacular
seaward-dipping sequence. The first hole to be drilled was planned to be drilled
second
but weak offshore ice in 1984 caused it to be drilled first. Thus CIROS-2 was
drilled in Ferrar Fjord through Quaternary and Pliocene sediment to basement at
165 mbsf in 212 m of water. CIROS-1, cored two years later in 1986, sampled 702
m of glacial marine strata from 22 to 36 million years ago before terminating at
the safe limit of the rig (results in NZ DSIR Bulletin 245, 1989).
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