Yvonne Scheidegger

Noble Gas Concentrations in Stalagmite Fluid Inclusions: a New Climate Proxy Yvonne Scheidegger

This work focuses on the determination of noble gas temperatures (NGTs) in water inclusions in stalagmites with the aim to infer the cave temperature prevailing at the time the inclusions were formed. The method is based on the temperature-dependent solubilities of noble gases (He, Ne, Ar, Kr and Xe) in water, which allows calculating the water temperature from measured noble gas concentrations if the salinity and the atmospheric pressure during gas exchange are known. Stalagmites are increasingly being used as climate archives, as they provide highly resolved and well-dated records of past climate conditions over glacial-interglacial time intervals. Stalagmites contain 0.01-0.1 wt.% of water, which is incorporated into the calcite crystals in the form of water inclusions during stalagmite growth. Noble gas analysis in water inclusions in stalagmites hence offers the potential to directly and quantitatively determine cave temperatures, which is an important prerequisite for the interpretation of stable isotope records in the stalagmite calcite.