Mineral and energy resource assessment of the Gallatin National Forest (exclusive of the Absaroka-Beartooth study area), in Gallatin, Madison, Meagher, Park, and Sweet Grass Counties, south-central Montana

Abstract

Bureau of Mines 1 (USBM) to conduct and coordinate mineral resource assessments for the USFS. These assessments were designed to assist the USFS in meeting the requirements of the Wilderness Act of 1964 and the Forest and Rangeland Renewable Resources Planning Act of 1974, as amended by the National Forest Management Act of 1976. This information is used by the USFS to help formulate plans for management of Federal lands for the reasonably foreseeable future. These plans are updated on a cyclic basis (10 to 15 years) to consider existing and future desired land conditions, to include up-to-date available scientific data, and to reflect current resource-management practices. In addition, the National Environmental Policy Act of 1969 requires the Federal land-management agencies to consider the best available scientific information when preparing environmental impact statements and issuing land-use decisions. Mineral resource assessments provide information about the types of rocks and mineral deposits that are present in an area, identify those parts of an area that are permissive for the occurrence of additional deposits of a specific mineral deposit type, and where the data are adequate, provide estimates of both the probable numbers of undiscovered deposits and the in-place resource. An assessment includes geologic maps as well as geochemical, geophysical, and mineral occurrence maps and information about the nature of potential undiscovered mineral deposits. In addition to providing answers to the questions what? where? and how much? with respect to mineral resources in the National Forests, these data can be combined with geoenvironmental models (du Bray, 1995) to evaluate environmental signatures for different types of mineral deposits. These data can also be used by ecologists and other scientists to delineate ecosystem subunits within Federal lands and to incorporate geologic information into other studies (for example, potential for natural or humaninduced acid drainage, habitat delineation, and potential nutrient availability). Historically, both the USGS and the USBM provided the USFS with minerals information from different perspectives. The USBM considered identified resource issues and the USGS focused on the geology and potential for undiscovered resources, as defined in 1980 (U.S. Bureau of Mines and U.S. Geological Survey, 1980). From 1990 to 1994, the USGS conducted a mineral and energy resource assessment of the Gallatin National Forest in Montana and the Custer National Forest in Montana and South Dakota. These studies evaluated the potential for the occurrence of undiscovered mineral resources and provided the USFS with current geologic and mineral-resource information. In 1993, the USBM completed an inventory and appraisal of identified mineral resources (that is, those resources for which location, quality, and quantity are already known) of the Gallatin National Forest. They also analyzed the socioeconomic impacts that might be derived from their development (Johnson and others, 1993). The ...