A stratigraphy-based method for reconstructing ice core orientation
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A stratigraphy-based method for reconstructing ice core orientation. / Westhoff, Julien; Stoll, Nicolas; Franke, Steven; Weikusat, Ilka; Bons, Paul; Kerch, Johanna; Jansen, Daniela; Kipfstuhl, Sepp; Dahl-Jensen, Dorthe.
In: Annals of Glaciology, Vol. 62, No. 85-86, 01.09.2021, p. 191-202.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - A stratigraphy-based method for reconstructing ice core orientation
AU - Westhoff, Julien
AU - Stoll, Nicolas
AU - Franke, Steven
AU - Weikusat, Ilka
AU - Bons, Paul
AU - Kerch, Johanna
AU - Jansen, Daniela
AU - Kipfstuhl, Sepp
AU - Dahl-Jensen, Dorthe
PY - 2021/9/1
Y1 - 2021/9/1
N2 - Ever since the first deep ice cores were drilled, it has been a challenge to determine their original, in-situ orientation. In general, the orientation of an ice core is lost as the drill is free to rotate during transport to the surface. For shallow ice cores, it is usually possible to match the adjacent core breaks, which preserves the orientation of the ice column. However, this method fails for deep ice cores, such as the EastGRIP ice core in Northeast Greenland. We provide a method to reconstruct ice core orientation using visual stratigraphy and borehole geometry. As the EastGRIP ice core is drilled through the Northeast Greenland Ice Stream, we use information about the directional structures to perform a full geographical re-orientation. We compared the core orientation with logging data from core break matching and the pattern of the stereographic projections of the crystals' c-axis orientations. Both comparisons agree very well with the proposed orientation method. The method works well for 441 out of 451 samples from a depth of 1375-2120 m in the EastGRIP ice core. It can also be applied to other ice cores, providing a better foundation for interpreting physical properties and understanding the flow of ice.
AB - Ever since the first deep ice cores were drilled, it has been a challenge to determine their original, in-situ orientation. In general, the orientation of an ice core is lost as the drill is free to rotate during transport to the surface. For shallow ice cores, it is usually possible to match the adjacent core breaks, which preserves the orientation of the ice column. However, this method fails for deep ice cores, such as the EastGRIP ice core in Northeast Greenland. We provide a method to reconstruct ice core orientation using visual stratigraphy and borehole geometry. As the EastGRIP ice core is drilled through the Northeast Greenland Ice Stream, we use information about the directional structures to perform a full geographical re-orientation. We compared the core orientation with logging data from core break matching and the pattern of the stereographic projections of the crystals' c-axis orientations. Both comparisons agree very well with the proposed orientation method. The method works well for 441 out of 451 samples from a depth of 1375-2120 m in the EastGRIP ice core. It can also be applied to other ice cores, providing a better foundation for interpreting physical properties and understanding the flow of ice.
KW - Glaciological instruments and methods
KW - ice core
KW - structural glaciology
KW - GREENLAND
KW - FLOW
KW - SHEET
KW - GRIP
KW - BOREHOLE
KW - VELOCITY
KW - GISP2
U2 - 10.1017/aog.2020.76
DO - 10.1017/aog.2020.76
M3 - Journal article
VL - 62
SP - 191
EP - 202
JO - Annals of Glaciology
JF - Annals of Glaciology
SN - 0260-3055
IS - 85-86
ER -
ID: 298374715