© Author(s) 2016. CC Attribution 4.0 License. British Society for Geomorphology Geomorphological Techniques, Chap. 3, Sec. 4.1 (2016) 3.4.1. Sampling and describing glacier ice Mario Toubes-Rodrigo 1 , Simon J. Cook 1 , David Elliott 1 , Robin Sen 1 1 School of Science and the Environment, Manchester Metropolitan University, Chester Street, Manchester, M1 5GD, UK (M.Toubes-Rodrigo@mmu.ac.uk) ABSTRACT: 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. KEYWORDS: cryofacies, glacial sediment, ice crystallography, sampling, stratigraphy Introduction Glaciers are highly heterogeneous in nature, comprising a wide variety of ice types with different characteristics. Traditionally, glaciologists and geomorphologists have focused on characterizing the physical and chemical nature of glacier and basal ice (e.g. Hubbard and Sharp, 1989; Knight, 1997), although increasingly, biological characteristics are being considered (e.g. Hodson et al., 2008; Montross et al., 2014). The diversity and complexity of ice types result from factors including flow and strain histories within the glacier; the character of parent snow, ice or water, as well as entrained sediment; sediment availability and processes of entrainment; melting and re- freezing; and many more (Hubbard and Sharp, 1989; Knight, 1997). Accounting for differences in ice composition is important. For example, ice characteristics (e.g. sediment content, structure, presence of chemical impurities) affect its rheological properties, and hence impact upon ice flow (e.g. Fitzsimons, 2006; Chandler et al., 2008). Equally, the origin and history of the ice can be interpreted from its physical characteristics (e.g. Knight, 1997; Hambrey and Lawson, 2000; Cook et al., 2010, 2011a; Lovell et al., 2015). For the most part, glacial geomorphologists are interested in the amounts of geomorphological activity (i.e. erosion and sediment transfer) achieved by glaciers (e.g. Hallet et al., 1996), and the deposition of sediment to create landforms and sediments, such as moraines and till (e.g. Cook et al., 2011b). Increasingly, however, there is recognition of the role of glaciers in global biogeochemical cycles (especially carbon), and the discharge of carbon and other nutrients to downstream ecosystems (e.g. Hood et al., 2015). Hence, there is a need to describe, sample and classify the different ice types that exist within glaciers. In this chapter, we outline how this is achieved, focusing on the basal zone of glaciers where ISSN 2047-0371