Inclusions in ice layers formed by melting and refreezing processes in a Greenland ice core
Abstract In recent decades, surface melting on the inland Greenland ice sheet has increased, leading to significant meltwater-refreezing in the snow and firn. Increased knowledge of the physical and chemical characteristics of these melt features (i.e., ice layers) is needed to help estimate future...
| Published in: | Journal of Glaciology |
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| Main Authors: | , , , , |
| Other Authors: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
2022
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1017/jog.2022.101 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022001010 |
| Summary: | Abstract In recent decades, surface melting on the inland Greenland ice sheet has increased, leading to significant meltwater-refreezing in the snow and firn. Increased knowledge of the physical and chemical characteristics of these melt features (i.e., ice layers) is needed to help estimate future global sea-level rise. Here, using a combination of microscopy and spectroscopy, we investigate the size, shape, location, and chemical compositions of inclusions in 12 ice layers of the SIGMA-A ice core in the northwestern Greenland ice sheet (78°03′06″N, 67°37′42″W, 1490 m a.s.l.). In the ice layers, we found inclusions exceeding 30 μm diameter that could only be formed by melting–refreezing, which we classify into columnar-, particle-, and rod-like inclusions. We propose that the smaller columnar- and particle-like inclusions of solid Na 2 SO 4 ⋅10H 2 O and CaSO 4 ⋅2H 2 O form first, within the ice grains, followed by the larger rod-like inclusions of brines with mainly Na + and Cl − in grain boundaries. Our results suggest a new proxy that may help identify past warm climates in deeper ice cores in Greenland and for studying future ice sheet melting behavior. |
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