Validation of sampling antarctic subglacial hypersaline waters with an electrothermal ice melting probe (IceMole) for environmental analytical geochemistry

• Main Authors: German, Laura, Mikucki, Jill A., Welch, Susan A., Welch, Kathleen A., Lutton, Anthony, Dachwald, Bernd (Prof. Dr.-Ing.), Kowalski, Julia (Dr. sc.), Heinen, Dirk, Feldmann, Marco (M.Sc.), Francke, Gero (M.Sc.), Espe, Clemens (B.Eng.), Lyons, W. Berry
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Antarctic; Taylor Valley; Antarc*; Antarctica
• Online Access: https://opus.bibliothek.fh-aachen.de/opus4/frontdoor/index/index/docId/9725

Geochemical characterisation of hypersaline waters is difficult as high concentrations of salts hinder the analysis of constituents at low concentrations, such as trace metals, and the collection of samples for trace metal analysis in natural waters can be easily contaminated. This is particularly the case if samples are collected by non-conventional techniques such as those required for aquatic subglacial environments. In this paper we present the first analysis of a subglacial brine from Taylor Valley, (~ 78°S), Antarctica for the trace metals: Ba, Co, Mo, Rb, Sr, V, and U. Samples were collected englacially using an electrothermal melting probe called the IceMole. This probe uses differential heating of a copper head as well as the probe’s sidewalls and an ice screw at the melting head to move through glacier ice. Detailed blanks, meltwater, and subglacial brine samples were collected to evaluate the impact of the IceMole and the borehole pump, the melting and collection process, filtration, and storage on the geochemistry of the samples collected by this device. Comparisons between melt water profiles through the glacier ice and blank analysis, with published studies on ice geochemistry, suggest the potential for minor contributions of some species Rb, As, Co, Mn, Ni, NH4+, and NO2−+NO3− from the IceMole. The ability to conduct detailed chemical analyses of subglacial fluids collected with melting probes is critical for the future exploration of the hundreds of deep subglacial lakes in Antarctica.