Greenland Ice Sheet Project

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GISP2 logo Logo gisp2 133x133.jpg
GISP2 logo

The Greenland Ice Sheet Project (GISP) was a decade-long project to drill ice cores in Greenland that involved scientists and funding agencies from Denmark, Switzerland and the United States. Besides the U.S. National Science Foundation (NSF), funding was provided by the Swiss National Science Foundation and the Danish Commission for Scientific Research in Greenland. The ice cores provide a proxy archive of temperature and atmospheric constituents that help to understand past climate variations.

Contents

The preliminary GISP field work started in 1971 at Dye 3 ( 65°N43°W / 65°N 43°W / 65; -43 (Dye 3) ), where a 372 meter deep, 10.2 cm diameter core was recovered. After this, annual field expeditions were carried out to drill intermediate depth cores at various locations on the ice sheet. The first was a 398 m core at Milcent and another was a 405 m core at the Crete station in 1974. After working out various logistical and engineering problems related to the development of a more sophisticated drilling rig, drilling to bedrock at Dye 3 began in the summer[ when? ] of 1979 using a new Danish electro-mechanical ice drill. In the first year, an 18 cm diameter hole was drilled and cased to a depth of 80 m. Coring continued for two more seasons, and on August 10, 1981, bedrock was reached at a depth of 2037 m. The Dye 3 site was a compromise: glaciologically, a higher site on the ice divide with smooth bedrock would have been better; logistically, such a site would have been too remote.

GISP drilling operations

GISP drilling operations [1]
YearLocationCoordinatesType of drillCore diam. (cm)Depth (m)Notes
1971Dye 3 65°11′N43°49′W / 65.183°N 43.817°W / 65.183; -43.817 Thermal10.2372CRREL thermal drill. [2]
1972North Site 75°46′N42°27′W / 75.767°N 42.450°W / 75.767; -42.450 SIPRE7.615
1972Crete 71°07′N37°19′W / 71.117°N 37.317°W / 71.117; -37.317 SIPRE7.615
1973Milcent 70°18′N45°35′W / 70.300°N 45.583°W / 70.300; -45.583 Thermal12.4398CRREL thermal drill. [2]
1973Dye 2 66°23′N46°11′W / 66.383°N 46.183°W / 66.383; -46.183 Shallow7.650
1974Crete 71°07′N37°19′W / 71.117°N 37.317°W / 71.117; -37.317 Thermal12.4405CRREL thermal drill. [2]
1974Dye 2 66°23′N46°11′W / 66.383°N 46.183°W / 66.383; -46.183 Shallow10.2101
1974Summit 71°17′N37°56′W / 71.283°N 37.933°W / 71.283; -37.933 Shallow7.631
1975Dye 3 65°11′N43°49′W / 65.183°N 43.817°W / 65.183; -43.817 Shallow7.695
1975South Dome 63°33′N44°36′W / 63.550°N 44.600°W / 63.550; -44.600 Shallow7.680
1975Hans Tausen 82°30′N38°20′W / 82.500°N 38.333°W / 82.500; -38.333 Shallow7.660
1976Dye 3 65°11′N43°49′W / 65.183°N 43.817°W / 65.183; -43.817 Wireline10.093CRREL wireline drill; test hole prior to sending the drill to the Ross Ice Shelf. [3]
1976Hans Tausen 82°30′N38°20′W / 82.500°N 38.333°W / 82.500; -38.333 Shallow7.650
1977Camp Century 77°10′N61°08′W / 77.167°N 61.133°W / 77.167; -61.133 Shallow7.6100
1977Dye 2 66°23′N46°11′W / 66.383°N 46.183°W / 66.383; -46.183 Shallow7.684
1977North Central 74°37′N39°36′W / 74.617°N 39.600°W / 74.617; -39.600 Shallow7.6100
1977Camp III 69°43′N50°08′W / 69.717°N 50.133°W / 69.717; -50.133 Shallow7.649
1978Dye 3 65°11′N43°49′W / 65.183°N 43.817°W / 65.183; -43.817 Shallow10.290
1978Camp III 69°43′N50°08′W / 69.717°N 50.133°W / 69.717; -50.133 Shallow7.680
1979-1981Dye 3 65°11′N43°49′W / 65.183°N 43.817°W / 65.183; -43.817 Thermal & electromechanical10.22037CRREL thermal drill to 80 m to install casing; Danish ISTUK EM drill from 80 m to bedrock. [1]

GISP2

There was a follow-up U.S. GISP2 project, which drilled at a glaciologically better location on the summit of the ice sheet. This hit bedrock (and drilled another 1.55 m into bedrock) on July 1, 1993 after five years of drilling, while European scientists produced a parallel core in the GRIP project. GISP2 produced an ice core 3053.44 meters in depth, the deepest ice core recovered in the world at the time. [4]

The location of the GISP2 drilling was revisited annually during summer campaigns to investigate the post-depositional properties of gasses and aerosols in the firn. Eventually, GISP2 and Summit Camp became the site of a year-round NSF / NOAA climate observatory and research facility known as the Greenland Environmental Observatory or GEOSummit. [5]

The bulk of the GISP2 ice core is archived at the National Ice Core Laboratory in Lakewood, Colorado, United States.

GISP2D1837 crop.jpg
Photograph of a section of the GISP2 ice core from 1837 m depth with clearly visible annual layers.

See also

References

  1. 1 2 Langway et al. (1985), p. 3.
  2. 1 2 3 Langway (2008), p. 28.
  3. Talalay (2016), p. 80.
  4. The GISP2 Ice Coring Effort, National Climatic Data Center
  5. NSF's Summit Greenland Observatory

Sources