GRIP Ice Core Texture and Fabric Data Thorsteinsson, T.; Kipfstuhl, J.; Miller, H. Thorsteinsson, T. Kipfstuhl, J. Miller, H. earth science/paleoclimate/ice cores (inclination,bulk ice,null,degree,null,ice cores,null,null,N,ice crystal inclination) earth science/paleoclimate/ice cores (grain size mean,bulk ice,null,millimeter,null,ice cores,null,null,N,average vertical crystal diameter) earth science/paleoclimate/ice cores (azimuth,bulk ice,null,degree,null,ice cores,null,null,N,ice crystal azimuth) earth science/paleoclimate/ice cores (ice age,null,null,calendar year before present,null,ice cores,null,null,N,null) 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 (GRIP>LATITUDE 72.58>LONGITUDE -37.63) A comprehensive study of textures and fabrics has been carried out on the Greenland Ice Core Project (GRIP) ice core. Crystal sizes and c axis orientations have been measured on thin sections with conventional techniques, yielding new information on the growth, rotation and recrystallization of ice crystals in the Greenland Ice Sheet. Normal grain growth is found to persist to a depth of 700 m in the core, where the onset of polygonization due to increasing strain prevents a further increase in grain size in the Holocene ice. Smaller crystals are observed in the Wisconsin ice, larger crystals are found in the Eemian ice, and the crystal size is found to vary with climatic parameters in these periods. This dependence, which probably results from variable impurity content in the ice, persists to a depth of 2930 m. Coarse-grained ice, probably resulting from rapid growth of crystals at comparatively high temperatures, is found in the lowest 100 m of the core. The data on c axis orientations reveal a steady evolution of the fabric from random near the surface to a strong single maximum in the lower part of the ice sheet. A significant strengthening is not observed at the Holocene-Wisconsin transition. The fabric development indicates that vertical compression at the ice divide is the main mode of deformation down to a depth of 2850 m. The evolution toward a single maximum fabric hardens the ice against vertical compression but softens it against simple shear. Evidence of simple shear deformation is clearly observed between 2850 m and 2950 m depth. Stretched fabrics in coarse-grained ice in the lowest 100 m could be due to tensional stresses; this ice is unlikely to be undergoing any significant horizontal deformation at the present time. STUDY NOTES: Average horizontal and vertical crystal diameters are given, obtained by linear-intercept measurements on thin sections. The data making up the 36 fabric diagrams published in the article (Thorstiensson, 1997) are included in a separate file. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Thorsteinsson, T. Investigator : Kipfstuhl, J. Investigator : Miller, H. 1997-11-30 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/17857 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/physical/fabric.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/physical/caxis.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/physical/fabric.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/physical/caxis.txt English https://www.ncdc.noaa.gov/paleo/study/17857 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/physical/fabric.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/physical/caxis.txt Thorsteinn Thorsteinsson, Josef Kipfstuhl, Heinz Miller1997Textures and fabrics in the GRIP ice coreJournal of Geophysical Research: Oceans102C1226583-2659910.1029/97JC00161http://onlinelibrary.wiley.com/enhanced/doi/10.1029/97JC00161/ START YEAR: 248000 cal yr BP * END YEAR: 375 cal yr BP -37.63 72.58 -37.63 72.58