Isotopic identification of subglacial processes ...

• Main Author: Maxwell, Michael
• Format: Text
• Language: English
• Published: University of British Columbia 2010
• Subjects: glacier*; Yukon
• Online Access: https://dx.doi.org/10.14288/1.0052631; https://doi.library.ubc.ca/10.14288/1.0052631

A comprehensive stable isotope study of basal ice and debris layers in two Yukon surging glaciers suggests an isotopically variable basal freezing cycle. Trapridge and Backe Glaciers, St. Elias Range, Yukon, Canada, have parallel basal debris layers that extend for hundreds of metres along marginal ice faces and in meltwater tunnels. The isotopic compositions of samples at 1-5 cm intervals from vertical ice cores in basal ice exposures, have the following characteristics: 1. The δO¹⁸ and δD values of ice immediately above a debris layer are higher than the values immediately below a debris layer (up to 3‰). 2. The δO¹⁸ and δD values vary between debris layers. The most common trend is an increase in δO¹⁸ and δD with decreasing height above the bed. 3. Clear ice layers, which are frequently immediately above debris layers, have higher δO¹⁸ and δD values than surrounding ice. 4. Across core lengths of 0.5-2.2 m, there is no significant overall isotopic shift from top to bottom of a core. Along a 100 m ...