| Summary: | Boreholes drilled to the bottom of ice stream B in the West Antarctic Ice Sheet reveal that the base of the ice stream is at the melting point and the basal water pressure is within about 1.6 bars of the ice overburden pressure. These conditions allow the rapid ice streaming motion to occur by basal sliding or by shear deformation of unconsolidated sediments that underlie the ice in a layer at least 2 meters thick. The mechanics of ice streaming plays a role in the response of the ice sheet to climatic change. © 1990 American Association for the Advancement of Science. Received 16 November 1989; accepted 30 January 1990. This work was supported by the U.S. National Science Foundation under grant DPP-8519083. We thank R. P. Scherer and H. A. Lowenstam for paleontological information and J. Chadwick, M. Wumkes, J. Berkey, H. Aschmann, M. Blume, H. Conway, S. Duncan, T. Svitek, and J. Zachariasen for help in the field work. Contribution No. 4791, Division of Geological and Planetary Sciences, California Institute of Technology.
|
|---|