BLUE JOINT WILDERNESS STUDY AREA, MONTANA, AND BLUE JOINT ROADLESS AREA, IDAHO.

During field studies of the Blue Joint Wilderness Study Area, Montana, and the Blue Joint Roadless Area, Idaho, areas of substantiated resource potential for epithermal precious-metal vein deposits were identified in areas of hydrothermal alteration and fossil hot springs activity in the Eocene volcanic rocks. Areas with substantiated resource potential for cobalt, copper, silver, and barite resources of the sediment-hosted type were identified in the Proterozoic quartz schist of the eastern part of the area. Probable potential exists for molybdenum in a prophyry system; anomalously high molybdenum values are coincident with high values for precious and base metals and uranium in some places. The geologic terrane precludes the occurrence of fossil fuel resources.