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3.3. Impacts on Geology and Soils Methodology Impacts on geology and soils were analyzed by reviewing information on geological resources in the park obtained from NPS geologists who were involved in internal scoping. ' The thresholds of change for the intensity of an impact are defined as follows: Negligible: An action that could result in a change to geology and soils, but the change would be so small that it would not be of any measurable or perceptible consequence. ' Minor: An action that could result in a change to geology and soils, but the change would be small and of little consequence. Moderate: An action that could result in a noticeable change to geology and soils; the change would be measurable and of consequence. Reclamation to offset these impacts would likely be successful. Major: An action that would result in a noticeable change to geology and soils; the change would be measurable and result in a severely adverse or major beneficial impact. The success of reclamation to offset these impacts cannot be guaranteed. The area of analysis for impacts to geological resources is defined as the pit area, north of the pit to the runoff drainage, south to the bottom of the slope, east to US 50, and west to the toe of the slope down to Beaver Creek. Affected Environment The Gunnison area lies in a transition zone between two physiographic provinces: the southern Rocky Mountains to the east and the Colorado Plateau to the west. In addition, it flies between two Tertiary volcanic centers: the West Elk Mountains to the north and the San Juan Mountains e to the south (Hansen 1965). The area of the Dickerson Pit composed mostly of Granite. Over time the Granite has been subject to erosion and the rocks have undergone an extremely long and complex period of deformation. The effects of the erosion and deformation have been the creation of the material to be mined at the pit, decomposed granite. Notwithstanding the geologic complexity of the site, the 1963 deed used the terms "decomposed granite and the materials intermixed therewith" to describe the materials which were to be included in the Dickerson family's mineral reservation. Presently, the extent of the "decomposed granite" and "intermixed materials" remaining at the site is unknown, since we cannot see below the surface of the ground, and since sampling would not necessarily yield an accurate picture of this jumbled deposit. Continued monitoring of the operation would be necessary to ensure that only the reserved materials are being mined and removed. (Figure 3.1 ). 39