Institute of Arctic and Alpine Research (INSTAAR), 1560 30th Street, Boulder, CO 80303, United States ; Department of Geography, University of Colorado, Boulder, CO 80309-0260, United States
British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham, NG12 5GG, United Kingdom
Institute of Arctic and Alpine Research (INSTAAR), 1560 30th Street, Boulder, CO 80303, United States ; Department of Geography, University of Colorado, Boulder, CO 80309-0260, United States
British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham, NG12 5GG, United Kingdom