DEVELOPING A PREDICTIVE EXPLORATION MODEL FOR MVT MINERALIZATION IN CENTRAL TEXAS: INSIGHTS FROM THE SOUTHEAST MISSOURI LEAD DISTRICT

Minor Pb-Zn occurrences on the flanks of the Llano Uplift in central Texas have many geologic similarities to the world-class Mississippi Valley Type (MVT) deposits of southeast Missouri. In both areas, mineralization is hosted in dolomitized Cambrian carbonates and appears favored in areas where local basement highs forced depositional pinchouts of the basal sandstone. In southeast Missouri, mineralization has been attributed to basinal fluid migration associated with Ouachita deformation and appears to be spatially related to regional faults that may have served as fluid conduits. In central Texas, there is also evidence that mineralization is associated with basinal fluids tied to Ouachita deformation and abundant regional faults serve as plausible fluid pathways. More unusually, southeast Missouri and central Texas are distinctly rich in Pb with respect to Zn, potentially resulting from their stratigraphic proximity to underlying granitic basement rocks. These numerous similarities suggest that a thorough understanding of spatial associations between sites of known mineralization and regional geology, geochemistry, and geophysics in southeast Missouri will be a useful guide in future exploration efforts in central Texas.

Regional datasets including geology, geochemistry, and geophysics are evaluated and ranked by the strength of their spatial association with known MVT deposits in southeast Missouri. These relationships are used to create a set of predictive models for southeast Missouri that are compared with a previously published predictive appraisal from the USGS Coterminous United States Mineral Assessment Program. Ultimately, the ranked factors related to mineralization in Missouri are used to generate a set of predictive mineralization models for central Texas that are evaluated based on their effectiveness in predicting the location of known surface and near-surface occurrences of MVT mineralization.