Proposed Title 1: - Queen's University

Regression to zero content of the sum SiO 2 and Fe 2 O 3 in the Athabasca-related U 6
uraninite gives a Chemical Pb age of 1619 Ma (Fig. 2.12D). This age overlaps the upper
intercept age of 1601±64 Ma and the 207 Pb/ 206 Pb age of 1620±4 Ma (Fig. 2.11F) and is
interpreted as the formation age of ±U 6 uraninite.
The higher degree of alteration of U 3 uraninite associated with the granite-related
metasomatic-type mineralization in Gunnar, as indicated by the much lower Pb contents
and the higher total silicate elements, is reflected by much lower Chemical Pb ages (Table
2.3). These ages range from 164 Ma to 0 and reflect recent alteration of U 3 uraninite in
Gunnar, which is also reflected by the low Pb/Pb and U-Pb ages (Tables 2.1 and 2.2).
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