| Summary: | Borehole observations from the base of the West-Antarctic Ice Sheet (WAIS) reveal the presence of a 10 to 15 m thick accretionary basal ice layer in the upstream area of Kamb Ice Stream (KIS). This ice layer has formed over a time of several thousand years by freeze-on of subglacial water to the ice base and has recorded during this time basal conditions upstream of its current location. Analysis of samples and videos sequences from boreholes drilled to the bottom of KIS confirms that KIS-stoppage was due to basal freeze-on and that relubrication of the ice stream is well underway. These results further suggest that ice stream cyclicity may be shorter than expected (1000s of years) and that a restart of KIS may be imminent within decades to centuries. © 2005 American Geophysical Union. Received 8 January 2005; accepted 12 May 2005; published 20 July 2005. We thank all members of the research team participating in the Sticky Spot field campaign 2000/01, in particular R. Bolsey. Additional members of the Caltech-NASA-JPL ice borehole camera team were K.Manatt, K. Boykins, R. Ivlev, F. Nicaise and R. Bolsey. We are grateful for helpful comments and review of the paper by E. D. Waddington, I. Howat and P.Christoffersen. A. E. Behar, F. D. Carsey, and I. Joughin performed this work at the JPL, Caltech, under contract with NASA. We thank NSF-OPP for logistical support of this and former S-157 field campaigns. Funding was provided by NSF grants OPP-9615420 and OPP-0096302. Published - Vogel2005p14502_Geophys_Res_Lett.pdf
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