|
|||||
|
|
Molar gas ratios of air entrapped in ice: A new tool to determine the origin of relict massive ground ice bodies in permafrost |
|
| Authors: | Raphaelle Cardyn Bernard Lauriol |
| Institution: | a Department of Earth Sciences, University of Ottawa, 140 Louis Pasteur, Ottawa, ON, Canada K1N 6N5 b Department of Geography, University of Ottawa, 60 University St., Ottawa, ON, Canada K1N 6N5 c National Glaciology Programme, Geological Survey of Canada (NRCan), 601 Booth St., Ottawa, ON, Canada K1A 0E8 d Centre d'Études Nordiques, Université Laval, Sainte-Foy, QC, Canada G1K 7P4 |
| Abstract: | The molar ratios of atmospheric gases change during dissolution in water due to differences in their relative solubilities. We exploited this characteristic to develop a tool to clarify the origin of ice formations in permafrost regions. Extracted from ice, molar gas ratios can distinguish buried glacier ice from intrasedimental ground ice formed by freezing groundwaters. An extraction line was built to isolate gases from ice by melting and trapping with liquid He, followed by analysis of N2, O2,, Ar, 18OO2 and 15NN2, by continuous flow mass spectrometry. The method was tested using glacier ice, aufeis ice (river icing) and intrasedimental ground ice from sites in the Canadian Arctic. O2/Ar and N2/Ar ratios clearly distinguish between atmospheric gas in glacial ice and gases from intrasedimental ground ice, which are exsolved from freezing water. δ15NN2 and δ18OO2 in glacier ice, aufeis ice and intrasedimental ground ice do not show clear distinguishing trends as they are affected by various physical processes during formation such as gravitational settling, excess air addition, mixing with snow pack, and respiration. |
| Keywords: | Molar gas ratios Glacier ice Massive ground ice Permafrost Canadian Arctic |
| 本文献已被 ScienceDirect 等数据库收录！ | |