Application of micro-X-ray fluorescence to chemical mapping of polar ice

Synchrotron-based micro-X-ray fluorescence (mu XRF) equipment has been used to analyze impurities in polar ice. A customized sample holder has been developed and the mu XRF equipment has been adapted with a thermal control system to keep samples unaltered during analyses. Artificial ice samples prepared from ultra-pure water were analyzed to investigate possible contamination and/or experimental artefacts. Analyses of polar ice from Antarctica (Dome C and Vostok) confirm this mu XRF technique is non-destructive and sensitive. Experiments can be reproduced to confirm or refine results by focusing on interesting spots such as crystal grain boundaries or specific inclusions. Integration times and resolution can be adjusted to optimize sensitivity. Investigation of unstable particles is possible due to the short analysis time. In addition to identification of elements in impurities, mu XRF is able to determine their speciations. The accuracy and reliability of the results confirm the potential of this technique for research in glaciology.