The ultramafic lamprophyres of the Illinois-Kentucky Fluorspar District (IKFD) are potential domestic sources of rare earth elements (REEs), but the role of mantle metasomatism and carbonate alteration in REE distribution is not well understood. Dr. Lukoczki’s team has employed petrographic and geochemical analyses to determine the nature of the mantle source region and timing of the carbonate mineralization. Carbonate alteration, including listwanitization and ophicalcitization, appear to play a secondary role in REE distribution. For details, find Zach Walton’s thesis here. The GEMS Lab will continue to support this research with advanced microscopic analyses, including fluid and melt inclusion studies, and Raman spectroscopy, providing insights into the processes controlling REE mineralization in the IKFD.

Kentucky hosts significant occurrences of fluorite, sphalerite, galena, and barite, concentrated in three key areas with historical production. In western Kentucky, part of the Illinois-Kentucky Fluorspar District, mineralization is linked to ultramafic intrusions, with notable germanium content in sphalerite. Southcentral Kentucky features sphalerite-dominated deposits similar to the Middle Tennessee Mines, with ongoing studies to assess germanium content. Central Kentucky, historically known for barite production, is the focus of a new Earth MRI project targeting critical mineral potential. The GEMS Lab will play a vital role in this research by utilizing advanced fluid inclusion analysis, Raman spectroscopy, and geochemical tracers to investigate the structural controls and fluid evolution responsible for these mineral occurrences. These tools, combined with high-resolution USGS geophysics, will provide critical insights into the genesis and exploration potential of Kentucky's mineral systems.

Sedimentary phosphate deposits are potential sources of rare earth elements (REEs) with the capacity to meet global demand. However, the processes influencing REE incorporation and distribution in these rocks—such as depositional environment, ocean chemistry, and post-depositional alteration—are not fully understood. The Ordovician Lexington Limestone in Kentucky, known for contributing to phosphate-rich soils supporting the state’s equine industry, also contains REEs and uranium, posing radon-related health risks. Dr. Lukoczki’s recently funded project applies crystallographic and geochemical tools to trace phosphate crystallization and recrystallization, uncovering the mechanisms controlling incorporation of trace elements like REEs and uranium in sedimentary phosphates.