TY - JOUR
T1 - Mineralogic investigation into occurrence of high uranium well waters in upstate South Carolina, USA
AU - Warner, Richard
AU - Meadows, Jason
AU - Sojda, Scott
AU - Price, Van
AU - Temples, Tom
AU - Arai, Yuji
AU - Fleisher, Chris
AU - Crawford, Bruce
AU - Stone, Peter
N1 - Funding Information:
The authors thank A.E. Drilling Services, Inc. (Mark Lassiter, President) for drilling and coring the well on Jenkins Bridge Road, and SC DHEC for defraying the expense of the well installation and the cost of having polished thin sections made from the core. Other funding support for this project was provided by the US EPA (Cooperative Agreement Number CR-83144301-0 to University of South Carolina) and by the Calhoun Honors College at Clemson University (Departmental Honors Research Grant to Jason Meadows). The first author is indebted to James Furr (currently with North Wind, Inc.) for calling his attention to the anomalously high-U well waters at Simpsonville at the outset of the discovery. Finally, we gratefully acknowledge Antonio Lanzirotti of the University of Chicago for his help with the synchrotron-based X-ray microprobe measurements and Craig Warner at the University of Florida for writing a computer program to calculate uraninite chemical ages. This manuscript has benefitted from detailed and thorough reviews by two anonymous reviewers and constructive comments supplied by Associate Editor Rich Wanty.
PY - 2011/5
Y1 - 2011/5
N2 - High levels of U (up to 5570 μg/L) have been discovered in well waters near Simpsonville, South Carolina, USA. In order to characterize the mineralogical source of the U and possible structural controls on its presence, a deep (214. m) well was cored adjacent to one of the enriched wells. The highest gamma-ray emissions in the recovered core occur in coarse biotite granite at a depth just below 52. m. A slickenlined fault plane at 48.6. m and narrow pegmatite layers at depths of 113, 203 and 207. m also yield high gamma-ray counts. Thin sections were made from the above materials and along several subvertical healed fractures. Uraninite and coffinite are the principal U-rich minerals in the core. Other U-bearing minerals include thorite and thorogummite, monazite, zircon and allanite. Primary uraninite occurs in the biotite granite and in pegmatite layers. Secondary coffinite is present as tiny (<5 μm) crystals dispersed along fractures in the granite and pegmatites. Coffinite also occurs along the slickenlined fault plane, where it is associated with calcite and calcic zeolite and also replaces allanite. Coffinite lacks radiogenic Pb, hence is considerably younger than the uraninite. Dissolution of partially oxidized Ca-rich uraninite occurring in the surficial biotite granite (or secondary coffinite in fracture zones) is likely the main source for the current high levels of U in nearby area wells. The high-U well waters have a carbonate signature, consistent with pervasive calcite vein mineralization in the core. Aqueous speciation calculations suggest U transport as an uranyl (U6+) hydroxyl-carbonate complex. Later reduction resulted in secondary precipitation along fractures as a U4+ mineral (i.e., coffinite).
AB - High levels of U (up to 5570 μg/L) have been discovered in well waters near Simpsonville, South Carolina, USA. In order to characterize the mineralogical source of the U and possible structural controls on its presence, a deep (214. m) well was cored adjacent to one of the enriched wells. The highest gamma-ray emissions in the recovered core occur in coarse biotite granite at a depth just below 52. m. A slickenlined fault plane at 48.6. m and narrow pegmatite layers at depths of 113, 203 and 207. m also yield high gamma-ray counts. Thin sections were made from the above materials and along several subvertical healed fractures. Uraninite and coffinite are the principal U-rich minerals in the core. Other U-bearing minerals include thorite and thorogummite, monazite, zircon and allanite. Primary uraninite occurs in the biotite granite and in pegmatite layers. Secondary coffinite is present as tiny (<5 μm) crystals dispersed along fractures in the granite and pegmatites. Coffinite also occurs along the slickenlined fault plane, where it is associated with calcite and calcic zeolite and also replaces allanite. Coffinite lacks radiogenic Pb, hence is considerably younger than the uraninite. Dissolution of partially oxidized Ca-rich uraninite occurring in the surficial biotite granite (or secondary coffinite in fracture zones) is likely the main source for the current high levels of U in nearby area wells. The high-U well waters have a carbonate signature, consistent with pervasive calcite vein mineralization in the core. Aqueous speciation calculations suggest U transport as an uranyl (U6+) hydroxyl-carbonate complex. Later reduction resulted in secondary precipitation along fractures as a U4+ mineral (i.e., coffinite).
UR - http://www.scopus.com/inward/record.url?scp=79953699611&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79953699611&partnerID=8YFLogxK
U2 - 10.1016/j.apgeochem.2011.01.035
DO - 10.1016/j.apgeochem.2011.01.035
M3 - Article
AN - SCOPUS:79953699611
SN - 0883-2927
VL - 26
SP - 777
EP - 788
JO - Applied Geochemistry
JF - Applied Geochemistry
IS - 5
ER -