THE BOTTOM TOPOGRAPHY OF GULKANA GLACIER, ALASKA RANGE, ALASKA,
Abstract
As an extension of an intensive study of Gulkana Glacier a 42 station gravimeter survey was made to gain some insight into its third dimension. This survey showed that the glacier's main tongue occupies a complex valley composed essentially of two parallel channels separated by a medial ridge which extends southward from rock bastions in the accumulation zone. At midglacier the ice thickness in the larger eastern channel is 225 m., in contrast to 130 m. in the western channel. The medial ridge degenerates down-glacier probably disappearing within 2 km. of the glacier terminus. The basic surface flow pattern of the glacier described by Moores can be adequately explained by this basal topography. Seasonal velocity variations are possibly caused by melt-water basal lubrication with one channel being favored over the other at different times of the year, in agreement with observations by Elliston on the Gorner-Gletscher, Switzerland, and with the glacier sliding theory of Weertman. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 18, 1964
- Accession Number
- AD0622721
Entities
People
- N. A. Ostenso
- P. V. Sellmann
- T. L. Pewe
Organizations
- University of Wisconsin–Madison