Microstructure, micro-inclusions, and mineralogy along the EGRIP (East Greenland Ice Core Project) ice core – Part 2: Implications for palaeo-mineralogy

Abstract. Impurities in polar ice do not only allow the reconstruction of past atmospheric aerosol concentrations but also influence physical properties ice. However, localisation impurities inside microstructure is still under debate and little known about mineralogy solid inclusions. In particular, general mineralogical diversity throughout an core specific distribution poorly investigated; impact on inclusions other processes thus hardly known. We use dust particle concentration, optical microscopy, cryo-Raman spectroscopy to systematically locate analyse micro-inclusions situ 11 samples from upper 1340 m East Greenland Ice Core Project core. Micro-inclusions are more variable than previously observed mainly composed mineral (quartz, mica, feldspar) sulfates (mainly gypsum). Inclusions same composition tend cluster, clustering frequency changes with depth. A variety dominate 900 m, while gypsum sulfate deeper samples, which however contain dust, nitrates, dolomite. The analysed part can be divided into two depth regimes different mineralogy, a lesser degree spatial distribution, could originate chemical reactions or large-scale cover northeast during mid-Holocene. complexity impurity metre scale centimetre underestimated, new methodological approaches necessary establish comprehensive understanding role impurities. Our results show that applying methods cores recognising its complexity, as well importance for studies, open avenues cores.