Mineral resource potential map of the northern part of the Washakie Wilderness and nearby roadless areas, Park County, Wyoming

Abstract

The northern part of the Washakie Wilderness and nearby roadless areas (hereafter referred to as study area) have been evaluated for mineral resource potential by a multidisciplinary team of geoscientists from the U.S. Geological Survey and the U.S. Bureau of Mines. The mineral potential was classified for 21 areas: (I) the Kirwin mining district adjacent to the Francs Peak Roadless Area has an identified porphyry copper deposit and also has high mineral resource potential for Cu, Pb, Zn, Ag, and Au in vein deposits; (2) the Stinkingwater mining district within the Washakie Wilderness has an identified Cu-Mo porphyry-type deposit and also has high potential for base-and precious-metal resources in veins; (3) the Meadow Creek area and (4) the Silver Creek area have high potential for Cu-Mo resources in a porphyry-type deposit; (5) Lost Ranger Top ("Birthday Basin") and (6) Yellow Ridge (both within the Washakie Wilderness) have high potential for Cu-Mo resources in porphyry-type deposits; (7) Robinson Creek, within the Washakie Wilderness, has moderate potential for Cu and Mo resources in porphyrytype deposits and moderate potential for base-and precious-metal resources in veins; (8) Eagle Creek, within the Washakie Wilderness, has high potential for base-and precious-metal resources in veins and high potential for Cu-Mo resources in a porphyry-type deposit; (9) Clouds Home Peak, also within the Washakie Wilderness, has high potential for base-and precious-metal resources in veins, and high potential for Cu-Mo resources in a porphyrytype deposit; (10) Deer Creek, within the Washakie Wilderness, has moderate potential for base-and preciousmetal resources in veins; and (II) the Gold Reef mining district, which is in the Francs Peak Roadless Area and has moderate potentfal for precious-and base-metal resources in veins. Ten other localities (Francs Fork, East Fork Pass, Reef Roadless Area, Sweetwater Creek, Ruth Creek, Rampart volcano, Ishawooa Creek, Anderson and Venus Creeks, Swede Creek, and Mount Burwell) have resource potential. Two of these areas (Francs Fork and East Fork Pass) have high resource potential for base and precious metals on the basis of geochemical and geophysical anomalies and a geological setting similar to some ore deposits in the region. Practically the entire study area, except in the vicinity of the igneous centers and the margins of intrusions, has low to moderate potential for resources of oil and gas in the sedimentary rocks below the volcaniclastic rocks. Oil seeps at Sweetwater Mineral Springs document the presence of oil beneath the volcaniclastic rocks. Regional stratigraphic and structural patterns also suggest that anticlines similar to those that produce oil and gas directly east of the study area are present under the study area; these anticlines probably are on a western platform extension of the petroleum-bearing Bighorn Basin, which lies to the east.