2022年7月27日
Development of crystal orientation fabric in the Dome Fuji ice core in East Antarctica: implications for the deformation regime in ice sheets
The Cryosphere
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- 巻
- 16
- 号
- 7
- 開始ページ
- 2985
- 終了ページ
- 3003
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.5194/tc-16-2985-2022
- 出版者・発行元
- Copernicus GmbH
Abstract. The crystal orientation fabric (COF) of a polar ice sheethas a significant effect on the rheology of the ice sheet. With the aim ofbetter understanding the deformation regime of ice sheets, the workpresented here investigates the COF in the upper 80 % of the Dome FujiStation ice core in East Antarctica. Dielectric anisotropy (Δε) data were acquired as a novel indicator of the verticalclustering of COF resulting from vertical compressional strain within thedome. The Δε values were found to exhibit a generalincrease with depth, but with fluctuations over distances in the order of10–102 m. In addition, significant decreases in Δεwere found to be associated with depths corresponding to three major glacialto interglacial transitions. These changes in Δε areascribed to variations in the deformational history caused by dislocationmotion occurring from near-surface depths to deeper layers. Fluctuations inΔε over distances of less than 0.5 m exhibited a stronginverse correlation with Δε at depths greater thanapproximately 1200 m, indicating that they were enhanced during theglacial-interglacial transitions. The Δε data alsoexhibited a positive correlation with the concentration of chloride ions andan inverse correlation with the amount of dust particles in the ice core atgreater depths corresponding to decreases in the degree of c axis clustering.Finally, we found that fluctuations in Δε persisted toapproximately 80 % of the total depth of the ice sheet. These data suggestthat the factors determining the deformation of ice include theconcentration of chloride ions and the amount of dust particles, and thatthe layered contrast associated with the COF is preserved all the way fromthe near-surface to a depth corresponding to approximately 80 % of thethickness of the ice sheet. These findings provide important implicationsregarding further development of the COF under the various stress-strainconfigurations that the ice will experience in the deepest region,approximately 20 % of the total depth from the ice/bed interface.
- リンク情報
- ID情報
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- DOI : 10.5194/tc-16-2985-2022
- eISSN : 1994-0424