Beacon Valley

Rock Glacier Surface Motion in Beacon Valley, Antarctica, from Synthetic-Aperture Radar Interferometry.

Rignot, Eric; Hallet, Bernard; Fountain, Andrew

Rignot, Eric: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099; e-mail: eric@adelie.jpl.nasa.gov

Hallet, Bernard: Quaternary Research Center, University of Washington, Seattle, WA, USA; e-mail:hallet@u.washington.edu

Fountain, Andrew: Departments of Geology and Geography, Portland State University, Portland, OR; e-mail:andrew@pdx.edu

Abstract

We present radar interferograms of rock glaciers in the Beacon Valley sector of the McMurdo Dry Valleys, in East Antarctica, as part of a comprehensive study of surface processes in the area. Due to the relative absence of precipitation (snow) in this region, the rock glaciers maintain excellent coherence of the radar returns over several years. As a result, we obtain a spatially continuous surface velocity field with a precision of fractions of a millimeter per year. On distinct rock glaciers entering Beacon Valley, we find coherent velocity patterns, with peak velocities approaching 40 mm per year. The ice supply from these rock glaciers nourishes the central portion of Beacon Valley, where velocities are found to be vanishingly small, and partly compensates for mass losses induced by sublimation. This analysis is consistent with the tantalizing notion that Beacon Valley ice is the oldest on Earth.

Interferogram of Beacon Valley, extending to the Taylor Glacier. Phase variations of +360o (or +28-mm displacement along the radar illumination) are colored from blue to purple, yellow and blue again, with a color intensity modulated by radar brightness. Larger image

Aerial photograph of Mullins and Friedman rock glaciers that enter Beacon Valley, Antarctica. TMA 3080 Frame 276 taken November 21, 1993, part of the Taylor Valley LTER series, US Geological Survey SCAR Library. Larger image

Return to Top