The Powderhorn Instant Study Area covers approximately 51,000 acres of land under BLM administration located about 80 km (50 mi) southwest of Gunnison, Colorado. A mineral resource survey, made in 1979 by the U.S. Geological Survey and the U.S. Bureau of Mines, indicates that both the mineral potential and the energy potential for the Powderhorn Instant Study Area are low. This report is based on geologic and geochemical investigations, examination of prospects, and an aeromagnetic survey. Spectrographic analyses were made of approximately 120 stream-sediment and rock samples. No mining districts are located within the study area.

Colorado↗

USGS1980

Mineral resource potential of the Centennial Mountains Wilderness Study Area, Beaverhead County, Montana, and Clark and Fremont Counties, Idaho

Geologists geochemists, and geophysicists of the U.S. Geological Survey and the U.S. Bureau of Mines have evaluated the mineral resource potential of the proposed Centennial Mountains Wilderness Study Area.

Idaho, Montana↗

USGS1977

Interpretation of an aeromagnetic anomaly in McMullen and Live Oak counties, Texas

An anomaly about 300 gammas in amplitude has been observed in data from an aerial magnetic survey flown over parts of Duval, Live Oak, McMullen, and Webb Counties, Tex. A two-and-one-half-dimensional model was used to iterpret the data, and the anomaly is apparently caused by a large mafic body centered near 28?10'N and 98?22'W, with an area of about 1800 km2 at a depth of 10 km.

Open-File Report↗