Using noble gas ratios to determine the origin of ground ice

Abstract

Argon, krypton and xenon have different solubilities in water, meaning their ratios in water are different from those in atmospheric air. This characteristic is used in a novel method to distinguish between ice bodies which originate from the compaction of snow (i.e. buried snow banks, glacial ice) vs. ice which forms from the freezing of groundwater (i.e. pingo ice). Ice which forms from the compaction of snow has gas ratios similar to atmospheric air, while ice which forms from the freezing of liquid water is expected to have gas ratios similar to air-equilibrated water. This analysis has been conducted using a spike dilution noble gas line with gas extraction conducted on-line. Samples were mixed with an aliquot of rare noble gases while being melted, then extracted gases are purified and cryogenically separated. Samples have been analysed from glacial ice, buried snow bank ice, intrusive ice, wedge ice, cave ice and two unknown ice bodies. Ice bodies which have formed from different processes have different gas ratios relative to their formation processes.

Greenhouse gas formation in ice wedges at Cyuie, central Yakutia

“…To better understand the ice wedge formation process, N 2 /Ar molar ratios (e.g., ) or other noble gas ratios (e.g., ) can be used. N 2 and noble gases are insensitive to biological activity and have different solubilities in water.…”

Anomalous Noble Gas Solubility in Liquid Cloud Water: Possible Implications for Noble Gas Temperatures and Cloud Physics

“…The results show a consistent pattern of He enrichment along with considerable depletion in Ar, Kr, and Xe. Ice and snow are extremely depleted in the heavy noble gases (Amalberti et al., 2018; Malone et al., 2010; Top et al., 1988; Utting et al., 2016) and it is natural to examine how one would expect water droplets that form from melting snow or ice pellets to evolve in terms of their noble gas concentrations during the course of falling to the ground. The question is, would one expect rain or small‐diameter cloud water droplets to retain any “memory” of an origin as ice and thereby present as water with He enrichment and heavy noble gas depletion?…”

“…For detailed controls on noble gas concentrations in ice, see Utting et al. (2016) and Amalberti et al. (2018).…”

“…This space is too small, however, for the three heaviest stable noble gases. For detailed controls on noble gas concentrations in ice, see Utting et al (2016) and Amalberti et al (2018).…”

87Sr/86Sr Ratios and Atmospheric Noble Gases in Theistareykir Geothermal Fluids: A Record of Glacial Water

“…Indeed, noble gas studies in rainfall (e.g., [87][88][89]) have highlighted the presence of different patterns for ANG other than simply atmospheric air. By contrast, ice bodies which originate from the compaction of snow (buried snowbanks, glacial ice) have ANG ratios close to those of atmospheric air because they trap air bubbles, while ice that forms from the freezing of liquid water (i.e., pingo ice) is expected to have ANG ratios similar to ASW because ANG are mainly dissolved at solubility equilibrium [90,91]. This is confirmed by the experimental data of Amalberti et al [92], who measured the noble gas signatures in snow.…”