Proposed Title 1: - Queen's University

U 5 uraninite yields two discordia lines. The concordia in Figure 2.11D has an upper
intercept age of 1783±7 Ma and a lower intercept of 71±79 Ma, with an oldest 207 Pb/ 206 Pb
age of 1812±15 Ma (2σ, MSWD: 6.2). The concordia in Figure 2.11E has an upper
intercept age of 1774±25 Ma and a lower intercept of 109±110 Ma (2σ, MSWD: 1.14).
The oldest 207 Pb/ 206 Pb age is 1800±37 Ma. The 207 Pb/ 206 Pb system records periods of
alteration at ca. 0.8-0.7 Ga and 0.4-0.3 Ga (Table 2.1).
2.4.4.1.6. Geochronology of the Athabasca-related ±U 6 :
U 6 uraninite gives a U-Pb concordia upper-intercept age of 1601±64 Ma and a lower
intercept of 441±92 Ma (2σ, MSWD: 10) (Fig. 2.11F). The oldest 207 Pb/ 206 Pb age of
1620±4 Ma is interpreted as the formation age. Post-mineralization alterations recorded in
the 207 Pb/ 206 Pb system occur at ca. 1.4-1.3 Ga and 0.4-0.3 Ga (Table 2.1).
2.4.4.1.7. Post-mineralization alteration events recorded in the U/Pb system
The U/Pb system records various episodes of post-mineralization alteration that have
affected all stages of the uranium mineralization. Results are presented in Figures 2.11G to
2.11N and summarized in Table 2.2b.
U/Pb age of the primary uranium mineralization
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