Editing Proxy (climate) (section)

====Drilling====

[[Image:Icecore 4x.jpg|thumb|Ice Core sample taken from drill. Photo by [[Lonnie Thompson]], [[Byrd Polar Research Center]].]] [[Ice cores]] are [[Core sample|cylindrical samples]] from within [[ice sheets]] in the [[Greenland]], [[Antarctic]], and [[North American]] regions.<ref name="Strom, Robert p. 255">Strom, Robert. ''Hot House.'' p. 255</ref><ref name="Core Location Maps.">[http://nicl.usgs.gov/coresite.htm "Core Location Maps."] {{webarchive|url=https://web.archive.org/web/20091110005705/http://nicl.usgs.gov/coresite.htm |date=2009-11-10 }}</ref> First attempts of extraction occurred in 1956 as part of the [[International Geophysical Year]]. As original means of extraction, the [[Cold Regions Research and Engineering Laboratory|U.S. Army's Cold Regions Research and Engineering Laboratory]] used an {{convert|80|ft|m|adj=on}}-long modified electrodrill in 1968 at [[Camp Century]], [[Greenland]], and [[Byrd Station]], [[Antarctica]]. Their machinery could drill through {{convert|15-20|ft}} of [[ice sheet|ice]] in 40–50 minutes. From 1300 to {{convert|3000|ft|m}} in depth, [[core sample]]s were {{convert|4+1/4|in}} in [[diameter]] and 10 to {{convert|20|ft|m}} long. Deeper [[core sample|samples]] of 15 to {{convert|20|ft|m}} long were not uncommon. Every subsequent [[drilling]] team improves their method with each new effort.<ref>Vardiman, Larry, Ph.D. ''Ice Cores and the Age of the Earth.'' p. 9-13</ref>