Antarctic Shallow Drilling Project provides key core samples

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Abstract

The understanding of Antarctica's climate, cryosphere, and biosphere evolution is limited, which is due in part to the paucity of outcrops and cores that record changes during the Tertiary. This problem has been partially rectified using conventional drill ships, such as the JOIDES Resolution, but access to key areas of the continental margin has been restricted because of the inability of these ships to operate in ice-covered waters. While researchers are restricted in their ability to acquire long cores in ice-prone areas, nature has provided an alternative method.

During past glacial maxima, ice sheets advanced onto the continental shelf, eroding deeply into the stratigraphic section. Several areas of the shelf are characterized by seaward dipping strata a few meters beneath the seafloor. However, these older strata are overlaid by glacial sediments that have proven to be impenetrable by standard piston coring. The Shallow Drilling Project (SHALDRIL) began with the idea of using an icebreaking vessel as the drill platform so that drilling could be conducted in areas that are inaccessible by standard drill ships.Though, even icebreaking vessels with a drill stem hanging beneath them are vulnerable to ever-present changes in sea state, winds, and ice conditions. Thus, the approach, by necessity, needs to be one of ‘drill and run.’ Two cruises, in the austral falls of 2005 and 2006, have shown the efficacy of this approach.

Ancillary