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This report compiles selected results from 13 U.S. Geological Survey (USGS) mineral resource assessment studies conducted in Idaho and Montana into consistent spatial databases that can be used in a geographic information system. The 183 spatial databases represent areas of mineral potential delineated in these studies and include attributes on mineral deposit type, level of mineral potential, certainty, and a reference. The assessments were conducted for five 1° x 2° quadrangles (Butte, Challis, Choteau, Dillon, and Wallace), several U.S. Forest Service (USFS) National Forests (including Challis, Custer, Gallatin, Helena, and Payette), and one Bureau of Land Management (BLM) Resource Area (Dillon). The data contained in the spatial databases are based on published information: no new interpretations are made. This digital compilation is part of an ongoing effort to provide mineral resource information formatted for use in spatial analysis. In particular, this is one of several reports prepared to address USFS needs for science information as forest management plans are revised in the Northern Rocky Mountains.

Aeromagnetic and gravity data provide confirmation of major structural and lithologic units in the southern Toquima Range, Nevada. These units include Cretaceous granite plutons and Tertiary calderas. In addition, the geophysical maps pinpoint numerous faults and lesser intrusions, and they suggest locations of several inferred subsurface intrusions. They also corroborate a system of northwesterly and northeasterly conjugate structures that probably are fundamental to the structural framework of the Toquima Range. A combination of geophysical, geochemical, and geologic data available for the widely mineralized and productive area suggests additional mineral resource potential, especially in and (or) adjacent to the Round Mountain, Jefferson, Manhattan, and Belmont mining districts. Also, evidence for mineral potential exists for areas near the Flower mercury mine south of Mount Jefferson caldera, and in the Bald Mountain Canyon belt of gold-quartz veins in the Manhattan caldera. A few other areas also show potential for mineral resources. The various geologic environments indicated within the map area suggest base- and preciousmetal potential in porphyry deposits as well as in quartz-vein and skarn deposits associated with intrusive stocks.

Unpublished mineral assessment reports of the Colville and Okanogan national forests (Chelan, Ferry, Okanogan, Pend Oreille, Skagit, Stevens, and Whatcom counties, WA) contain data on 3,934 samples analyzed for gold, silver, copper, lead, zinc, molybdenum, tungsten and uranium. Data presented here were obtained by R.A. Grant (1982a,b) for an assessment of the mineral potential of these national forests during 1979-1982 under a contract from the USDA-Forest Service.

Wadi-sediment samples were collected from 450 sites in a 580-km2 area (sample density 1.5 per km2) as part of an exploration program designed to assess the mineral potential of the Farah Garan Kutam mineral belt and to evaluate mineralization at the Farah Garan ancient working (DGMR Project 3.03.10). Demagnetized panned-concentrate and sieved minus-80-mesh fractions were prepared from each bulk sample of approximately 5 kg. The fractions were analyzed for silver, arsenic, copper, lead, and zinc by atomic-absorption methods and for gold by an atomic-absorption graphite-furnace method. The analytical results for the panned-concentrate samples delineate 21 anomalies, and the results for the minus-80-mesh samples delineate 24. Of the latter, 14 are coincident with panned-concentrate anomaly areas, whereas 10 are uniquely defined. The analytical results of the panned-concentrate samples uniquely define two areas. Overall, the panned-concentrate samples yielded threshold values higher than the threshold values for the minus-80-mesh samples (for gold, 10 times higher), and delineate anomalous areas larger than those for the minus-80-mesh samples. This observation is consistent with the results of similar surveys elsewhere in the Arabian Shield, which indicate that panned-concentrate samples more effectively outline geochemical anomalies than sieved fine-grained samples. In the present survey, geochemical anomalies locate all the sites of mineralization known from previous work. The survey is therefore technically a success. However, a large number of these anomalies probably result from contamination of the wadi systems by metal dispersed from ancient mine workings, and this particular survey, overall, may be of limited value as a guide to the discovery of hitherto unknown mineralization. Nevertheless, the survey outlines two areas that may mark extensions to known mineralization, and a number of other areas in which no mineralization is known. Based on a consideration of the character of the bedrock geology, the value of each reported analytical result in relation to the respective element thresholds, and the number of anomalous samples that cluster in any given area, four areas are recommended for high-priority follow-up sampling.

The following report is an evaluation of the mineral potential of the Lone Peak Wilderness study area, Utah.

The US Bureau of Mines and the US Geological Survey appraised the mineral resources and mineral resource potential of this area that is about 45 mi west of Salt Lake City. Inferred subeconomic resources of sand and gravel and of limestone suitable for use in making cement exist within this study area, but these are not likely to be developed. There are no other identified resources in this study area. Roughly the southern half and the northeastern corner of this study area have a moderate mineral resource potential for undiscovered lead, zinc, silver, gold, and mercury in vein and replacement deposits and for undiscovered sediment-hosted, disseminated gold resources. The remaining parts of this study area are assigned a low mineral potential for these types of resources. A small area at the southwestern corner of this study area may contain thermal waters and is assigned a moderate potential for undiscovered geothermal resources. This entire study area has a low potential for oil and gas resources.

This report contains statements made by U.S. representatives before the Economic and Technical Subcomittee of the United Nations Committee on the Peaceful Uses of the Seabed and Ocean Floor Beyond the Limits of National Jurisdiction during its March 1969 meeting. The titles of the statements are: Subsea physiographic provinces and their mineral potential; Progress in the exploration and exploitation of subsea petroleum resources and its implications for development beyond the limits of national jurisdiction; Progress in the exploration and exploitation of hard minerals from the seabed; Potential ill effects of subsea mineral exploitation and measures to prevent them; Topographic and geologic mapping of the sea bottom; The origin, incidence, effects, and means of prevention and control of oil-well blowouts; and Implications of geologic and economic factors to seabed resource allocation, development, and management. (MPG)