Proposed Title 1: - Queen's University

4.5.4.2. Pb-Pb geochronology of galena and uraninite by LA-HR-ICP-MS
The Gn 1 Galena- Au 1 gold- U 1 uraninite assemblage from the Coronation Hill deposit
has been dated by means of Pb-Pb dating of cogenetic Gn 1 galena (Table 4.6). A Pb-Pb
isochron from Gn 1 galena in equilibrium with Au 1 gold and U 1 yields an age of 1601±98
Ma (Fig. 4.13A) recording a period of post-ore alteration coincident with the timing of
unconformity-related U mineralization in the Kombolgie Basin (Gulson and Mizon, 1980;
Page et al., 1980; Maas, 1989; Polito et al., 2004). This event is also identical to alteration
periods recorded in the U-Pb system in U 1 uraninite (Figs. 4.12D, 4.12C and 4.12E).
The Pb-Pb system in uraninite from various samples records periods of postmineralization
alteration events as well. Model ages obtained are 1412±86 Ma (Fig. 4.13B),
1282±54 Ma (Fig. 4.13C), 790±240 Ma (Fig. 4.13D), 719±110 Ma (Fig. 4.13E), and
377±67 Ma (Fig. 4.13F).
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