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An ice core is a core sample that is typically removed from an ice sheet or a ... the field work included several intermediate-depth cores, at Dye 3 (372 m in 1971 ...
Core Institution or project Coords Altitude (metres) Drill dates Depth (metres) Sources Lewis Glacier 1, Kenya University of East Anglia: 4880 1975 6 [1] Lewis Glacier 1, Kenya University of East Anglia 4880 1977 11 [1]
The core goes back 740,000 years and reveals 8 previous glacial cycles. Drilling was completed at this site in December 2004, reaching a drilling depth of 3270.2 m, 5 m above bedrock. Present-day annual average air temperature is −54.5 °C and snow accumulation 25 mm/y. Information about the core was first published in Nature on 10 June 2004. [2]
In 1991, ice cores 783 to 2482 meters long were drilled, and an ice core was drilled to bedrock in 1992. [13] The ice core was first taken to the University of Copenhagen in Denmark, where it was stored in a cold room at -26 °C. [13] Five sections of ice core with a length of about 300 to 400 mm were shipped to Japan. [13]
The ice cores provide a proxy archive of temperature and atmospheric constituents that help to understand past climate variations. Annual field expeditions were carried out to drill intermediate depth cores at various locations on the ice sheet: Dye 3 in 1971 to 372 m; North Site (75°46’N 42°27’W, 2870 masl) in 1972 to 15 m
The ice core samples taken from the base are still cited in research, according to William Colgan, a climate and glacier scientist at York University in Toronto, Canada, ...
The ice must be cut through, broken up, or melted. Tools can be directly pushed into snow and firn (snow that is compressed, but not yet turned to ice, which typically happens at a depth of 60 metres (200 ft) to 120 metres (390 ft)); [22] this method is not effective in ice, but it is perfectly adequate for obtaining samples from the uppermost layers. [23]
An ice core which contains samples of Earth’s atmosphere from five million years ago has been pulled up from the continent’s Ong Valley, researchers have said.