The drilling site of the North Greenland Ice Core Project (NGRIP or NorthGRIP) is near the center of

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

(75.1 N, 42.32 W, 2917 m, ice thickness 3085). Drilling began in 1999 and was completed at

bedrock In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of bed ...

in 2003. The cores are cylinders of ice 11 centimeters in diameter that were brought to the surface in 3.5-meter lengths. The NGRIP site was chosen to extract a long and undisturbed record stretching into the last

glacial A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

, and it succeeded. The site was chosen for a flat basal

topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the landforms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sci ...

to avoid the flow distortions that render the bottom of the GRIP and GISP cores unreliable. Unusually, there is melting at the bottom of the NGRIP core – believed to be due to a high

geothermal Geothermal is related to energy and may refer to: * Geothermal energy, useful energy generated and stored in the Earth * Geothermal activity, the range of natural phenomena at or near the surface, associated with release of the Earth's internal he ...

heat flux locally. This has the advantage that the bottom layers are less compressed by thinning than they would otherwise be: NGRIP annual layers at 10.5 kyr age are 1.1 cm thick, twice the GRIP thicknesses at equal age. The NGRIP record helps to resolve a problem with the GRIP and GISP2 records – the unreliability of the

Eemian Stage The Last Interglacial, also known as the Eemian, was the interglacial period which began about 130,000 years ago at the end of the Penultimate Glacial Period and ended about 115,000 years ago at the beginning of the Last Glacial Period. It cor ...

portion of the record. NGRIP covers 5 kyr of the Eemian, and shows that temperatures then were roughly as stable as the pre-industrial

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

temperatures were. This is confirmed by

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

cores, in particular MD95-2042. In 2003, NGRIP recovered what seem to be plant remnants nearly two miles below the surface, and they may be several million years old. "Several of the pieces look very much like blades of grass or pine needles," said University of Colorado at Boulder geological sciences Professor James White, an NGRIP principal investigator. "If confirmed, this will be the first organic material ever recovered from a deep ice-core drilling project," he said.

References

External links

The original web page of the NGRIP project with field diaries and pictures. * https://web.archive.org/web/20120101002118/http://www.gfy.ku.dk/~www-glac/ngrip/index_eng.htm The NGRIP project was run by an international consortium of scientists, and drilling and logistics were managed by what is now called Centre for Ice and Climate at the Niels Bohr Institute, University of Copenhagen, Denmark. This research centre maintains a web page about ice core research: * http://www.iceandclimate.nbi.ku.dk/research/drill_analysing/history_drilling/search_eemian/ {{coord, 75, 01, N, 42, 32, W, source:kolossus-eswiki, display=title Geochronological institutions and organizations Natural history of Greenland Arctic research 20th century in the Arctic 21st century in the Arctic

See also

References

External links