noaa-icecore-17856 GRIP Ice Core Basal Ice Crystal Size Data Thorsteinsson, T.; Kipfstuhl, J.; Eicken, H.; Johnsen, S.J.; Fuhrer, K. GRIP Ice Core Basal Ice Crystal Size Data 1997-11-30 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/17856 Investigator T. Thorsteinsson Investigator J. Kipfstuhl Investigator H. Eicken Investigator S.J. Johnsen Investigator K. Fuhrer earth science paleoclimate ice cores grain size mean,bulk ice,null,millimeter,null,ice cores,null,null,N,average horizontal crystal diameter earth science paleoclimate ice cores depth,null,null,meter,null,ice cores,null,null,N,null earth science paleoclimate ice core physical properties geoscientificInformation 248000 cal yr BP 230000 cal yr BP Complete 72.58 72.58 -37.63 -37.63 Continent North America Greenland GRIP>LATITUDE 72.58>LONGITUDE -37.63 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Thorsteinn Thorsteinsson, Josef Kipfstuhl, Hajo Eicken, Sigfus J. Johnsen, Katrin Fuhrer 1995 Earth and Planetary Science Letters 131 3-4 381-394 10.1016/0012-821X(95)00031-7 http://www.sciencedirect.com/science/article/pii/0012821X95000317

Continuous measurements of ice crystal size have been carried out on an 80 m sequence between 2790 and 2870 m depth in the GRIP ice core from Central Greenland. The ice in this interval is at present considered to orginate from the Eemian interglacial period. The record reveals that the crystal size in ice older than 100,000 yr is highly dependent on climatic conditions at the time of snowfall. This dependence shows up as a strong correlation between d18O values and crystal size throughout the Eemian, as well as a negative correlation between crystal size and several soluble and insoluble impurities. Although high-resolution impurity records are available from selected parts of the Eemian ice, the study is not conclusive on which impurities are most effective in slowing grain growth. It is shown that the normal grain-growth process, commonly observed in the upper few hundred metres of polar ice sheets, does not yield grain sizes compatible with observed ones at this depth in the ice sheet, even in those parts of the Eemian ice where impurity drag effects are not present. Polygonization of crystals within the ice sheet and the nucleation and rapid growth of new grains at relatively high temperatures in the lowest part probably play an important role in producing the observed grain-size variations. The relevance of possible flow disturbances of the GRIP Eemian climatic record for the results presented is discussed briefly. STUDY NOTES: Crystal sizes in basal GRIP ice, average horizontal crystal diameter in mm.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/physical/xlsize.txt Data File; GRIP Basal Ice Crystal Sizes USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11