Summary: | A basal zone, tens of meters thick, of debris-laden ice was observed in Kamb Ice Stream, West Antarctica, using a video camera lowered into boreholes made by hot-water drilling. The debris content varies, sometimes abruptly, forming a sequence of layers that reflect the complex history of fast ice flow and bed interaction. In most parts, the concentration of debris is low, a few percent by weight, with particles, often mud clots, dispersed in a matrix of clear ice. The nature of the debris distribution can be interpreted in terms of specific time intervals in the history of fast motion of Kamb Ice Stream including processes leading up to the termination of its streaming behavior and possible reactivation. © 2013 International Glaciological Society. Publication date: 2013-07-01. The results presented here are based on a research program initiated by the visionary Barclay Kamb, who persisted in studying the basal conditions of fast-moving glaciers and ice streams in situ. I am extremely grateful for his keen interest and constant support. I am very grateful to our field assistants, who showed great enthusiasm and unrelenting dedication even under demanding circumstances. The 2000/ 01 drilling team included Shulamit Gordon, Matt Bachmann, Daniel Abrams, Stefan Vogel, Regina Sterr, Kate Batten, Michele Koppes and Robin Bolsey. The JPL/Caltech camera design team also included Frank Carsey, Lonne Lane, Robert Ivlev, Ken Manatt, Kobie Boykins, Jason Feldman, Fabien Nicaise, Kai Zhu and Alberto Behar. Alberto Behar was also crucial for the video image acquisition. Bjorn Johns of the University Navstar Consortium (UNAVCO) helped with the precision GPS measurements. The comments of my reviewers and editors greatly improved the paper. I also appreciate the help of a great number of support people, especially my late wife Luise Engelhardt. The US National Science Foundation Office of Polar Programs funded this work under grant OPP-9615420. Published - Engelhardt_2013p287.pdf
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