20-EPN2-095: Carbon Isotopic Fractionation and Quantification in Perennial Cave Ice
Visit by Artur Ionescu of the Babes-Bolyai University (Romania), to TA2 Facility 17 – Isotoptech Stable/Clumped Isotopes Laboratory (Hungary).
Dates of visit: 27 November – 08 December 2023.
Report Summary: The aim of this project is to investigate the carbon isotopic variation in perennial cave ice in different phases, for the determination of fractionation processes and estimation of the carbon source (organic or inorganic). To do so, we aim of using two types of samples, the first from extracted ice from perennial cave glacier and ice created in laboratory conditions. We measured δ13C in gases trapped as “bubbles” in the ice mainly CO2, in dissolved carbon in the ice as HCO3 and CO3, and in the cryogenic cave carbonates.
Our hypothesis presumes that isotopic fractionation of carbon could shift an inorganic signature towards a more organic one, thus making it difficult to assess the origin of carbon, hence misinterpreting the origin.
In total 36 measurements have been performed on carbon-13. Our preliminary data on the fractionation of carbon-13 show that during freezing the bubbles “concentrate” the light isotopic ratios while the most enriched values were found in the cave carbonates. Thus confirming our hypothesis. This is the first study that described isotopic values of carbon-13 in the different phases of the cave ice, however more laboratory experiments are needed to better constrain the isotopic fractionation process.
