MINERALOGY AND RADIOGENIC ISOTOPES OF A NEWLY IDENTIFIED ZINC VEIN NEAR RUSSELLVILLE, KENTUCKY

Mississippi Valley-type (MVT) deposits are found globally within a range of mineralogic characteristics, formed as a product of fluids driven out of foreland basins during orogenic events. MVT deposits are known to be a source of lead, zinc, barite, fluorspar, and some deposits in Tennessee have known byproducts of gallium and germanium. MVT deposits may also be a source of critical metals such as indium, rhenium, and platinum group elements. Further research of the regional trends and occurrences can help answer questions about these deposits, including the source of the metals and the timing of the large ore-forming systems.

Here we describe preliminary results from a newly identified surface vein located ~2.5 miles southeast of Russellville, Kentucky, along the Russellville Bypass completed in late 2017, near the intersection with Nashville St. The limestone formation at the site was determined to be the Renault Limestone and the mineralogy was determined to be predominately coarse-grained, translucent-white calcite (CaCO3), with opaque Fe-poor sphalerite (ZnS) and translucent-brownish fluorite (CaF2). Sphalerite crystals range from 2 mm to 10 cm in size, fluorite crystals range from 2 mm to euhedral cubes 1 cm in size. The vein is ~30 cm in size with a strike at 13 degrees and a nearly sub-vertical dip.

Fluorite Sm-Nd and sphalerite Rb-Sr will be used to determine ages of mineralization to compare with other MVT deposit ages in the Central Tennessee, East Tennessee, and Kentucky-Fluorspar districts. Trace element and REE analysis of sphalerite and fluorite samples will help to identify the potential for overlooked critical metals and uniqueness of this occurrence from others in the surrounding MVT districts.