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Title: Shear moraines in the Thule area, northwest Greenland
Authors: University of Denver.
Northwestern University (Evanston, Ill.)
Bishop, Barry C.
Keywords: Moraines
Glacier ice
Ice creep
Ice surface features
Glacier albation
Thule, Greenland
Publisher: U.S. Army Snow, Ice, and Permafrost Research Establishment.
Engineer Research and Development Center (U.S.)
Series/Report no.: Research report (U.S. Army Snow
Description: Technical report
Summary: The ice-cored moraine which occurs on the margin of the Greenland Ice Cap, east of Thule Air Base, was investigated during the summers of 1954 and 1955. A synthesis of the field data gathered leads to the following conclusions: 1.) The outer zone of the ice margin is composed of stagnant ice which acts as a barrier to movement of mobile ice from the interior. 2.) The mobile ice overrides the barrier zone in a series of high angle imbricate shears. 3.) These shears carry old ground moraine from the subglacial floor toward the surface. 4.) Differential ablation on the surface results in the formation of ice-cored moraine ridges, parallel to the strike of the shear. 5.) Recent stagnation and recession of the ice margin in the Thule area has resulted in the formation of a belt of successive shear moraines. 6.) Geomorphic processes in addition to ablation (particularly wind action) control the surface expression of the shear moraines. 7.) Subglacial topography is the primary control on the trend of both ice edge and moraine ridges. 8.) The complex Thule Ramp shear moraine has resulted from a faster-moving ice mass to the north overriding the Thule Ramp ice. 9.) The prominent ice cliffs are manifestations of erosion by wind and water. 10.) The tunnel in the Thule Ramp ice cliff indicates a former development of shear moraine in the area. 11.) Structural and geomorphic features indicate glacial cycles in the area of both long and short duration. 12.) The shear moraines in the Thule area offer a possible explanation for the mode of ground moraine deposition in some areas of continental glaciation during the late Pleistocene. The work done in 1954 and 1955 was in the nature of a glacial geomorphologic reconnaissance. Intensive study remains to be done, particularly in the Thule Ramp area, on ice structure, movement, and ablation before a complete understanding of both present and past glacial regimes can be reached. NOTE: This is a large file. Allow your browser several minutes to download the file.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Research Report

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