Raman spectroscopy of micro-inclusions in Antarctic ice cores
The climatologic interpretation of greenhouse gases extracted from inclusions in ice cores is hampered by a severe lack of knowledge about the processes governing their entrapment and subsequent evolution. The transition from air bubbles to crystalline air hydtrates (clathrates) can significantly alter the gas mixing ratios, due to processes which are little understood. High-resolution CO2 measurements indicate, that the speed of the enclathration process varies substantially, even between neighbouring layers. Linescanner data reveal peculiar clear layers, where the bubble-clathrate transition is already completed, throughout the transition zone.
With Micro Raman spectroscopy, gas contents of individual inclusions can be analysed. The dedicated innovative cryo-Raman spectrometer at AWI Bremerhaven provides excellent spatial resolution and is optimized for fast automated mapping acquisitions of frozen samples. To improve our understanding of the above mentioned processes and observations, this project will includes systematic mapping of the gas contents of bubbles/clathrates inside significant layers, mapping and comparison of whole clathrate clusters to determine the formation path and mapping and identification of solid inclusions to determine their role in nucleation.