This report is the product of a 4-year project of the U.S. Geological Survey (USGS) under the Conterminous United States Mineral Assessment Program (GUSMAP) to assess mineral resources of the Charlotte l°x2° quadrangle, North Carolina and South Carolina (fig. 1). Data on geology, mineral-deposit occurrences, geochemistry, heavy minerals, and geophysics available in September 1981 have been integrated into a multidisciplinary analysis of the mineral-resource potential of the quadrangle. In addition, the relative importance of different commodities of the area is evaluated from records of past production through 1978. The results of CUSMAP for the Charlotte quadrangle are presented here and in related map reports of the U.S. Geological Survey (see Gairand others, 1986). Stone, sand and gravel, clay, and 17 types of metallic and other nonmetallic mineral deposits are evaluated. Commodities produced from these deposits at the present time or in the past, or those judged potentially available, are base metals (copper, lead, and zinc), gold, silver, lithium, tin, beryllium, iron, thorium (monazite), rare earths, zirconium, barite, sul-fur, feldspar, mica, corundum, kyanite and sillimanite, quartz, and rutile.
The general arrangement of this report and the plan for the resource assessment follow rather closely the outlines of several earlier CUSMAP reports, particularly the report on the Rolla l°x2° quadrangle, Missouri (Pratt, 1981). The methods of mineral-resource assessment used in that report, and generally followed here, were evolved at a mineral-resource assessment work
shop in Golden, Colo., in December 1979 (Shawe, 1981). The principal steps in the assessment (Pratt, 1981), as adapted to the Charlotte quadrangle area, are
1. Compilation of geologic, geochemical, and geophysical maps to identify the geologic environments of the area.
2. Determination of the types of known mineral deposits and of mineral commodities derived from these deposits and identification of commodities that are potentially derivable, as inferred from geochemical and heavy-mineral data obtained during this study.
3. Construction of descriptive models for the known mineral-deposit types by assembly of criteria that characterize the deposits.
4. Systematic correlation of geologic, mineral-occurrence, geochemical, mineralogic, and geophysical1 data and comparison of the data with features of the descriptive models.
Evaluations of 17 types of metallic-nonmetallic mineral deposits and of stone, sand-gravel, and clay construction materials, with geologic, geophysical, and geochemical background information. Includes black and white geologic map at 1:250,000 scale. Edited by Jacob E. Gair, 1989. 171 pages.