Origin of ridge-top depressions by large-scale creep in the Olympic Mountains, Washington

Bulletin of the Geological Society of America
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Abstract

In the high mountain area of the Olympic Mountains, Washington, there are many troughlike depressions on and essentially parallel to ridge tops. The troughs are mostly developed on rocks with strong planar anisotropy: slate, sandstone, and phyllite. Similar features in Europe, Japan, and New Zealand have been variously ascribed to erosion, slow movement along deep-seated shear planes, creep, and tectonic movements. In the Olympics, many depressions parallel structure; one wall is steeply dipping rocks, the other shattered, gently dipping rocks. These depressions seem to be the gaps left between undisturbed steeply dipping rocks and beds or cleavage bent valley-ward by creep. A few troughs may be the result of slow down-slope movement along deep-seated shear planes; this is a favorite explanation of eastern European workers. The Olympic ridge-top depressions testify to the importance of gravity in the degradation of high mountains carved from weak rocks.

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Publication type Article
Publication Subtype Journal Article
Title Origin of ridge-top depressions by large-scale creep in the Olympic Mountains, Washington
Series title Bulletin of the Geological Society of America
DOI 10.1130/0016-7606(1971)82[1811:OORDBL]2.0.CO;2
Volume 82
Issue 7
Year Published 1971
Language English
Publisher Geological Society of America
Description 12 p.
First page 1811
Last page 1822
Country United States
State Washington
Other Geospatial Olympic Mountains
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