Sampling and Describing Glacier Ice
Determination of the physical, chemical and biological properties of glacier ice is essential for many aspects of glaciology and glacial geomorphology. In this chapter, we draw principally on examples of the description and sampling of the basal zone of glaciers where the ice is in direct contact with its substrate, and hence is where a great deal of geomorphological work is achieved. Whilst a pre-determined sampling strategy is essential to inform sampling equipment requirements, flexibility in data collection is necessary because of the dynamic nature of glaciers, and variability of ice exposure. Ice description is best achieved through stratigraphic logging, section drawing and photography. Detailed description can include a variety of information about the nature of layering, structures and sediment distribution; the size, shape and roundness of included debris; ice crystallography; and bubble content. It is common practice to categorise descriptively different ice types into cryofacies, so that comparisons can be made between studies. Sample extraction may be required for more detailed analyses of the physical, chemical and microbiological composition of the ice. We outline the use of a number of tools for ice sample extraction, including chainsaws, ice axes, chisels and ice screws.