The reduction of chloride ion concentration in basal ice near Hamna Icefall, East Antarctica

元データ 国立極地研究所

概要

The present paper mainly discusses chloride ions (Cl^-) in debris-laden basal ice near Hamna Icefall, Queen Maud Land, East Antarctica. The basal ice consists of alternating layers of bubble-free and bubbly ice of the order of mm to cm in thickness. Detailed analyses of Cl^- and stable isotopes (δ^<18>O and δD) on the alternating layers were performed. The Cl^- concentrations in the bubble-free ice layers and in the bubbly ice layers whose isotopic fluctuations decrease from neighboring bubble-free ice layers are reduced compared to those in the bubbly ice layers having quasi-neutral values on the isotopic profile. The reduction of Cl concentration in frozen ice compared to that in pre-freezing water was also observed from an experiment on ion fractionation by freezing. These results suggest that the bubble-free ice layers and the bubbly ice layers whose isotopic fluctuation is decreased from that in neighboring bubble-free ice layers were formed by melt-refreezing processes. The reduction of Cl concentration in the basal ice is considered to be an indicator to distinguish whether the basal ice has experienced melt-refreezing or not.

著者

Watanabe Okitsugu National Institute of Polar Research, Research Organization of Information and Systems
Watanabe Okitsugu National Institute Of Polar Research
Iizuka Yoshinori National Institute of Polar Research
Satake Hiroshi Department of Environmental Chemistry and Biology, Toyama University
Satake Hiroshi Department Of Environmental Biology And Chemistry University Of Toyama
Satake H Department Of Environmental Chemistry And Biology Toyama University

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