Proposed Title 1: - Queen's University

e the same as the U 3 -mineralizing fluid. Therefore, the source of U 3 uraninite in the
granite-related mineralization was likely the Gunnar granitic rock itself. U 3 uraninite could
have been transported by cooling exsolved residual magmatic hydrothermal fluid at ca.
315 o C during magmatic-hydrothermal degassing and deposited in voids left after Qtz 1
quartz and Cal 5 calcite dissolution. The negative chondrite normalized Ce anomaly could
be related to Ce-absorption in Mnz 1 monazite during U 3 uranium precipitation. The high
REE content in the metasomatizing brine is likely related to trace element fractionation
into the fluid during its separation from the granitic melt (e.g. Giere, 1986). Abundant F
within the syn-ore minerals and the presence of Mnz 1 monazite intergrown with U 3
uraninite, suggest that P and F were important ore transporting complexes and that U 3
uranium transfer into the exsolved magmatic-hydrothermal solutions was as uranylfluorine-phosphate
complexes (e.g. U(HPO 4 ) 2 and UF 4 ). The negative chondrite
normalized Eu anomaly (Fig. 3.10A) indicates that the hydrothermal mineralizing fluid
was reduced and that magmatic-fluid degassing processes may have caused the loss of a
large volume of CO 2 that destabilized U and REE complexes, thereby promoting the
deposition of U 3 mineralization.
The style of the granite autometasomatism and the mechanism of ore-forming
processes are similar to deposits in the Xiazhuang district (e.g. Zhushanxia, and Xiwang
deposits), southern China (Du Letian, 1986), the albitized granite-hosted U mineralization
in Brazil (Porto da Silveira et al., 1991) and France (Leroy, 1978). At the Gunnar deposit,
U 3 mineralization is later overprinted by the breccia- (U 4 ) and volcanic-type (U 5 )
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