Economic Geology; December 2006; v. 101; no. 8;
p. 1613-1622; DOI: 10.2113/gsecongeo.101.8.1613
© 2006 Society of Economic Geologists
Scientific Communications |
TRACE ELEMENT AND Sr-Nd ISOTOPE GEOCHEMISTRY OF FLUORITE FROM THE XIANGSHAN URANIUM DEPOSIT, SOUTHEAST CHINA
Yao-hui Jiang
,
Hong-fei Ling,
Shao-yong Jiang,
Wei-zhou Shen,
Hong-hai Fan and
Pei Ni
State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, P.R. China
Corresponding author: e-mail, yhj186{at}hotmail.com
The trace element and Sr-Nd isotope geochemistry of fluorite have been investigated in the Xiangshan volcanic rock-hosted uranium deposit in southeast China. Detailed Sr-Nd isotope data of the hydrothermal fluorite closely associated with the uranium mineralization suggest that ore-forming fluids were a combination of mantle-derived fluid and fluids equilibrated with basement metamorphic rocks. This model is consistent with previously published H-O isotope data and is incompatible with meteoric water as the only ore-forming fluid. Trace element geochemical profiles across the uranium orebody can be interpreted to reflect reaction between the host rocks and a mantle-derived fluid containing high U and Th with low Th/U ratios. The mantle-derived fluid is considered to have been U-, F- and carbonate-rich. Mixing with shallowly circulated meteoric water within the fractures of the host volcanic rocks caused dilution and cooling of the ore-forming fluid and subsequent precipitation of fluorite and uranium ore.
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