Insoluble and soluble impurities, enclosed in polar ice sheets, have a major impact on the deformation behaviour of the ice. Large-, Macro and Micro-scale deformation observed in ice cores has been retraced to impurities in the ice, and therefore the exact location of the impurities is important. Over the years different techniques have been developed to analyse the location, and chemistry, of impurities and the following figures are examples of general methodological concepts.
1_cloudy_bands_details.jpg displays a sample from a depth of 1917 m from the East Greenland Ice Core Project (EGRIP) deep ice core, NE-Greenland; the drilling has started in 2016 and is still on-going. A) shows a Visual Stratigraphy image, which was taken in June 2019 by Nicolas Stoll at the EGRIP drill site. It shows cloudy bands and the stratigraphy of the ice sample, covering a few years of age, and is used to count annual layers, and to derive information about the deformation of ice. B) and C) are microstructure maps of the same sample, created by Nicolas Stoll in July 2020 at the Alfred Wegener Institute, Bremerhaven following the technique described by Kipfstuhl et al. (2006). These show grain sizes- and shapes, grain boundaries and sub-grain boundaries in detail to derive information about the deformation of ice.
4_microstructure.jpg are microstructure maps of an EGRIP ice core sample from a depth of 757.4 m, created by Nicolas Stoll in July 2020 at the Alfred Wegener Institute, Bremerhaven following the technique described by Kipfstuhl et al. (2006). These show grain sizes- and shapes, grain boundaries, sub-grain boundaries, and micro-inclusions in detail to derive information about the location of inclusion in ice.
5_SEM_EDML.jpg are Scanning Electron Microscope images taken by Ilka Weikusat at the University of Utrecht in 2011. The sample from a depth of 2035.9 m is from the European Project for Ice Coring in Antarctica in Dronning Maud Land (EDML) deep ice core, drilled between 2001 and 2006 at Kohnen Station, Antarctica. The SEM-images were created in preparation for Electron backscatter diffraction measurements and show ice grain boundaries, frost and a filament at a grain boundary. M. Drury and G. Pennock provided the infrastructure for Cryo-SEM work, which was conducted at EM square, the electron microscopy facility of Utrecht University Weikusat et al. (2017).
6_Ramam_multiplot.jpg were created by Nicolas Stoll in March 2020 at the Alfred Wegener Institute, Bremerhaven using Cryo-Raman spectroscopy to identify the chemistry of micro-inclusions in an ice sample from a depth of 757.4 m from the EGRIP ice core, NE-Greenland. A) and B) show the location of micro-inclusions and C) is the derived Raman spectra of the micro-inclusion in B), which was identified as Quartz.
