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Cryoplanation terraces of interior and western AlaskaCryoplanation terraces are step- or table like residual landforms consisting of a nearly horizontal bedrock surface covered by a thin veneer of rock debris and bounded by ascending or descending scarps or both. Among examples studied, rubble-covered scarps range in height from 3 to 76 m and slope from 9 deg to 32 deg; nearly vertical scarps exist where bedrock is exposed or thinly buried. Simple transverse nivation hollows, which are occupied by large seasonal snow banks, commonly indent the lower surfaces of sharply angular ascending scarps. Terrace treads slope from 1 deg to 10 deg and commonly cut across bedrock structures such as bedding, rock contacts, foliation, joints, faults, and shear zones. Debris on terrace treads is generally 0.8-2.5 m thick. Permafrost table is generally present from 0.5 to 2 m below the tread surface. Permafrost is shallowest in the floors of nivation hollows and deepest in the well-drained margins of terrace treads. Side slopes of cryoplanation terraces are shallowly buried bedrock surfaces that are littered with a variety of mass-movement deposits.
Document ID
Document Type
Conference Paper
Reger, R. D. (Geological and Geophysical Surveys Fairbanks, AK, United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1993
Publication Information
Publication: Lunar and Planetary Inst., Workshop on the Martian Northern Plains: Sedimentological, Periglacial, and Paleoclimatic Evolution
Subject Category
Distribution Limits
Work of the US Gov. Public Use Permitted.

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