Metallic mineral-resource potential of the Rolla 1° x 2° quadrangle, Missouri, as appraised in September 1980

Abstract

Data on the mineralization, areal geology, structure, stratigraphy, sedimentary facies, petrology, trace-element geochemistry, and aeromagnetic and gravity patterns of the Rolla I°x2° quadrangle have been integrated to provide a basis for a September 1980 appraisal of the metallic mineralresource potential of the quadrangle. The appraisal method consisted of six steps:(1) Compilation of geologic, lithofacies, geochemical, and geophysical maps of the quadrangle to identify the known and inferred geologic environments present.(2) Determination of types of mineral deposits that could reasonably be expected to occur in the quadrangle on the basis of favorable geologic environments and known mineral occurrences.(3) Development of conceptual, descriptive models of the various geologic parameters that characterize these mineral-deposit types.(4) From each descriptive model, derivation of diagnostic and permissive "recognition criteria" for the occurrence or non-occurrence of that type of mineral deposit. Diagnostic criteria are those that are associated with all or nearly all known deposits and generally may be considered to be requisite to the presence of a deposit. Permissive criteria are those that are associated with enough known deposits that they may be considered to favor the presence of a deposit, although they are not required. manganese in Precambrian and sedimentary rocks, and marcasite-pyrite-hematite, residual iron, and copper deposits in sedimentary rocks, but such deposits would not be commercial in the near future because of their small size and (or) unfavorable mineralogy. The quadrangle has low potential for coastal plain-type uranium deposits, base and precious metals in Precambrian quartz veins, and massive sulfide deposits.

Map showing mineral resource assessment for vein and replacement deposits of gold, silver, copper, lead, zinc, manganese, and tungsten in the Butte 1° x 2° quadrangle, Montana

“…Much of the modeling approach and the use of favorable criteria was first applied by Pratt (1981) to the Rolla, Missouri, quadrangle. Harrison and others (1986b) adapted and expanded the methodology to the Wallace quadrangle.…”

“…For some studies, where there are only two or three data sets of low complexity, GIS may not be advantageous, but where the number of data sets is large and kinds of data are more complex, the manual or visual approach can analyze these data objectively and uniformly only with the expenditure of large amounts of time if at all. The manual approach to CUSMAP mineral assessment was used by Pratt (1981 ), Pratt and others (1984), and Harrison, Leach, and Kleinkopf (1986b), and a comparison of manually derived results with those obtained using a GIS-based approach was made by Pratt and others (1983). For the mineral resource assessment of the Butte quadrangle, GIS technology and procedures offered great advantages because of the large number of data sets, the complexity of the data, and the lack of personnel and time to perform manual analyses of the data.…”