Rare Earth Mineral Concentrations in Ultramafic Alkaline Rocks and Fluorite Within the Illinois-Kentucky Fluorite District: Hicks Dome Cryptoexplosive Complex, Southeast Illinois and Northwest Kentucky (USA) Proceedings of the 47th Forum on the Geology of

ABSTRACT The rare earth elements (REE) are composed of the Lanthanide Series of 15 elements with atomic numbers (57) through (71) and yttrium (39). Because of their geochemical behavior, REE rarely form their own minerals and more commonly are found incorporated within the structure of other minerals. There is growing concern over the economical availability of REE because of their diverse and expanding array of technological applications and limited supply. This paper presents the results of a mineralogical and geochemical study of fluorite ore, ultramafic rock, and igneous breccia from the IllinoisKentucky Fluorite District (United States). Igneous rocks and fluorite ore were analyzed through whole-rock trace element geochemistry and electron microscopy to determine the relative abundance of REE. Geochemical analysis (inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry) from outcrop samples at the Sparks Hill Diatreme (Hardin County, Illinois) detected elevated concentrations of cerium group or light REE: lanthanum (La, 293 ppm), cerium (Ce, 467 ppm), praseodymium (Pr, 45.5 ppm), and neodymium (Nd, 143 ppm RELEVANCE OF THE STUDY In 2010, as part of an Illinois statewide geologic mapping program (STATEMAP), a geochemical analysis of an igneous breccia detected 293 ppm of lanthanum and 467 ppm of ceriu

Microbial oxidation of Fe2+ and pyrite exposed to flux of micromolar H2O2 in acidic media

At an initial pH of 2, while abiotic oxidation of aqueous Fe2+ was enhanced by a flux of H2O2 at micromolar concentrations, bio-oxidation of aqueous Fe2+ could be impeded due to oxidative stress/damage in Acidithiobacillus ferrooxidans caused by Fenton reaction-derived hydroxyl radical, particularly when the molar ratio of Fe 2+ to H2O2 was low. When pyrite cubes were intermittently exposed to fluxes of micromolar H2O2, the reduced Fe2+-Fe 3+ conversion rate in the solution (due to reduced microbial activity) weakened the Fe 3+-catalyzed oxidation of cubic pyrite and added to relative importance of H2O2-driven oxidation in the corrosion of mineral surfaces for the treatments with high H 2O2 doses. This had effects on reducing the build-up of a passivating coating layer on the mineral surfaces. Cell attachment to the mineral surfaces was only observed at the later stage of the experiment after the solutions became less favorable for the growth of planktonic bacteria

Identification of Multiple Mercury Sources to Stream Sediments near Oak Ridge, TN, USA

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155735/1/Donovan_et_al_2014_Identification_of_multiple.pd

Sources and cycling of mercury in the paleo Arctic Ocean from Hg stable isotope variations in Eocene and Quaternary sediments

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155764/1/Gleason_et_al_2017_Sources.pd