Abstract
Abstract. A 5.28 m-long ice core was extracted from a major cave ice body in the Mammuthöhle cave system. The upper ~1.2 m of ice most likely originate from precipitation fallen before the 1960s (based on <8.5 TU). Characteristic fluctuations in electrical conductivity were observed in the cave ice profile, which seem to mirror the fluctuation of karst and surface water in the water supply of the ice accumulation. The stable isotope composition does not support the hypothesis that ice layers with low conductivity are formed by freezing out of water vapour. Isotope fractionation effects during the freezing process are indicated by the enrichment of heavy stable isotopes (2H, 18O) in the ice compared to the potential sources (local precipitation, karst water) and by the characteristically low d-excess values. In addition, the cave ice water line shows a slope coefficient of 8.13. A two-component open-system model (i.e. a depleted component mixed with the freezing water) can adequately explain the measured isotopic compositions of the Saarhalle cave ice.
Highlights
Mid-latitude glaciers are well–known archives of past environmental conditions (e.g. Wagenbach, 1989; Schwikowski, 2004)
The relative importance of these sources can vary from cave to cave and it is unrealistic to expect that a single model can be used to interpret environmental proxies from cave ice deposits
Serial 3H measurements is a powerful tool to date cave ice deposited from precipitation during the past ∼60 yr (Horvatincic 1996; Horvatincicand Krajcar-Bronic, 1998; Kern et al, 2009b)
Summary
Mid-latitude glaciers are well–known archives of past environmental conditions (e.g. Wagenbach, 1989; Schwikowski, 2004). Researchers have started to explore previously neglected low-accumulation environments (Wagenbach and Spotl, 2010) such as miniature ice caps (Haeberli et al, 2004) and perennial cave ice accumulations (Claussen et al, 2007; Holmlund et al, 2005; Turri et al, 2009; May et al, 2011). The latter, can have a complex origin as their water can be derived from snow, freezing karst water, or freezing out (re-sublimation) of water vapour. Detailed studies are required for each individual ice cave to understand these systems (Yonge and MacDonald, 2006; Turri et al, 2009)
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