GIS STATISTICAL ANALYSES OF THE UPLAND MESAS AND BUTTES IN THE WIND RIVER MOUNTAIN RANGE, WYOMING

Imported topographic maps into GIS, recent satellite images, and field work were used to produce an alpine-geomorphic map of the Wind River Mountains (WMR), in northwestern Wyoming. The most notable, pervasive, predominant, and aerial extensive geomorphic features mapped were upland glaciated mesas and buttes. These nearly flat-topped to gently-rolling glacially eroded bedrock landmasses, rise distinctly and abruptly above the deeply scoured alpine glacial valleys. Statistically measureable parameters used to define, measure, and analyze these features were: bedrock type, orientation, slope direction, slope, and active Holocene glaciers.

Preliminary observations indicate that the upland butte density is highest in an area of a former large ice center and distal to the mesas, where as upland mesa density is highest away from these former ice centers and along the sides. The largest mesas are on the eastern slopes of the WRM, indicating the possibility of a very large ice mass that originating in the Green River Valley (GRV), topping the WRM, and spreading outward into the Wind River Valley. Glacial geomorphic mapping of: cirques, compound cirques, deeply carved bedrock u-shaped valleys, overridden horns, horns, as well as active Holocene glaciers, indicated a definitive spatial relationship to the upland mesa and buttes.

Statistical analysis of these mapped features will aid in determining the possible origin and extent of ice coverage, paleo-ice flow patterns, and the glacial history of the WRM, as well as their relationship to the surrounding Green River and Wind River valleys. Current distribution of these features as well as the active Holocene glaciers suggests that at one time ice nearly covered the entire core of the WRM, and the majority of the GVR, except for the highest peak, Gannett.