Preliminary results of induced polarization-resistivity surveys in the Northgate district, Colorado

Induced polarization (I.P.) and resistivity surveys were made at selected locations in the Northgate district, Jackson County, Colorado. The objectives of the study were (1) to determine the feasibility of detecting and delineating pyrite-altered zones adjacent to fluorsparmineralized veins, and (2) to locate buried or obscured extensions of these fluorspar veins.

The Northgate fluorspar deposits are among the largest in the western United States and have been commercially mined on a large scale since 1951. These deposits are being studied by Ronald G. Worl, U.S. Geological Survey, as part of an investigation of zoning in low-temperature barite, fluorite, and manganese oxide hydrothermal deposits. Of prime interest is the hypothesis that these deposits may form halos around adjacent base or precious metal deposits.