Hydrogen isotope determination by TC/EA technique in application to volcanic glass as a window into secondary hydration

Overall our results support the use of H-isotopes of volcanic glass to discuss the composition of meteoric waters and paleo-climate within a specific region. To this purpose, the volcanic glass has to be almost fully rehydrated in order to fingerprint the isotopic composition of the ambient environmental water. As rehydration is exponentially faster with increasing temperature, efficient rehydration taking months to years, may occur in a cooling volcanic deposits that are meters-thick and thus can remain at a few hundred °C for a years to hundreds of years after the eruption. Such deposits could then provide a snap-shot view of climatic conditions at the time of the studied eruption.