POTENTIAL FOR ECONOMICALLY VIABLE PLACER DEPOSITS WITHIN THE BLACK AND ST. FRANCIS RIVERS, SAINT FRANCOIS MOUNTAINS, SOUTHEASTERN MISSOURI

Obtaining mineral resources from exposed outcrops and subsurface deposits within the mid-continent region of the United States has a long and rich history. Within the last two decades, there has been an increase in the necessity of valuable mineral deposits because of the increase in technology usage in our daily lives. While thus far, there has been a focus on subsurface mining, there is potential for alluvial placer deposits. In southeastern Missouri, economic potential has been identified in, and realized from, exposed Precambrian igneous rocks and hydrothermally altered lower Paleozoic sedimentary rocks within the viburnum trend. However, these rocks have a protracted exhumation and exposure history within a mature landscape with multiple streams and rivers, which could potentially host economic deposits from the exposed bedrock. Here we present preliminary findings from sediment samples retrieved from the Black and St. Francis Rivers, and associated tributaries surrounding the Saint Francois Mountains. Powdered material was analyzed using X-Ray fluorescence for (a) rare earth elements, iron, and cobalt, which are found in the Precambrian igneous rocks, and (b) lead, silver, copper, barite, and zinc, which have been historically produced by mining lower Paleozoic carbonate rocks in the viburnum trend. These preliminary findings suggest economic potential exists, but wider investigation is necessary to determine the economic viability of these deposits.