WMOD00314

• Project Name: Uintah Ecology Project
• Title: Potential Ecological Impacts of Snowpack Augmentation in the Uintah Mountains, Utah
• Date: 4/20/1981
• State: UT
• Weather Modification - Doc Type: Report

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in northwestern Colorado. Deep crustal movements have pushed the crest

of the anticline northward until it is asymmetrical with a steep nor-

thern face and a more gentle south slope.

Except for a few igneous dikes intruded into the oldest sedimentary

rocks in the range, the High Uintas are composed entirely of sedimentary

materials (Hansen 1969). For the most part, igneous activities have

been absent during the development of the range (Enunons 1907). The

ravages of some 70 million years of erosion have stripped off the

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younger geologic strata from the apex of the Uinta anticline leaving

quartzites of the Uinta Mountain group of Precambrian age to dominate

most of the landscape above 3,050 m elevation. The generally reddish

colored Uinta Mountain Quartzite is hard and deficient in the elements

required by plants, thus soils develop slowly on that parent material

and are inherently infertile.

The high elevation interior of the range has been further modified

by four major glacial events during Pleistocene times (Grogger 1974).

During the first and most extensive glaciation, over 2,500 km2 of the

range were buried under ice (Hansen 1969), and valley glaciers advanced

beyond the mountain fronts on both the north and south slopes of the

Uintas and coalesced to form extensive piedmont glaciers (Grogger 1974).

Today the evidence of glaciation in the form of mountain lakes, mor-

aines, cirques, and U-shaped valleys can be seen throughout the High

Uintas.

Glaciation has enhanced the depressing effect of hard and nutrient

poor rock on plant growth in the Uintas by scouring away or burying such

soils as had developed prior to the Pleistocene at high elevations.

Shallow, impoverished soils combine with short growing seasons and cold