Proposed Title 1: - Queen's University

Volcanic-type ±U 5 (Sample 6139, Gunnar deposit). F: Athabasca-related ±U 6 (Sample 2202,
Martin Lake deposit). G: Altered metasomatic-type U 3 (Sample GN-42, Gunnar deposit). H:
Altered breccia-type U 4 at Gunnar (Sample VR, Gunnar deposit). I: Altered breccia-type U 4
(Sample C23-116, Cinch Lake deposit). J: Altered metasomatic-type U 3 (Sample 6134,
Gunnar deposit). K: Altered Athabasca-related ±U 6 (Sample EA3011, Eagle-Ace). L: Altered
volcanic-type ±U 5 (Sample AE3010, Eagle-Ace deposit). M: Altered metasomatic-type U 3
(Sample VR69190, Gunnar deposit). Note: Data-point error ellipses are 2σ. Plots were
constructed using ISOPLOT ver. 3.2 (Ludwig 2000) from the isotope ratios and their
respective errors are presented in Table 2.1. 207 Pb/ 206 Pb ages are reported along discordia line,
the oldest 207 Pb/ 206 Pb age is shown in bold character for concordia of the primary U
mineralization.
2.4.4.2. Chemical Pb age of the uranium mineralization
Regression of the sum SiO 2 , Fe 2 O 3 , CaO and MnO contents to zero in the early veintype
±U 2
uraninite corresponds to 2290 Ma (Fig. 2.12A), which is identical to the
207 Pb/ 206 Pb formation age of 2293±17 Ma (Fig. 2.11B). Chemical Pb ages show alteration
events at ca. 1800 Ma, 1600 Ma, 1200 Ma, and 170 Ma (Table 2.3).
Chemical Pb ages derived from the composition of the breccia-type U 4 uraninite vary
from 1315 Ma to 557 Ma. The intercept at zero content of elements other than uraninite
gives an age of 1830 Ma (Fig. 2.12B), which is close to the 207 Pb/ 206 Pb formation age of
1848±5 Ma (Fig. 2.11D).
The zero intercept of the Chemical Pb age of the volcanic-type ±U 5
uraninite
corresponds to 1827 Ma (Fig. 2.12C), which overlaps the 207 Pb/ 206 Pb ages of 1812±15 Ma
and 1800±37 Ma (Figs. 11D and 11E, respectively). The concordance of these ages is
interpreted as the crystallization age of ±U 5 uraninite. Chemical Pb ages display alteration
events at ca. 1800-1700 Ma, 1500-1400 Ma, and 1300-1200 Ma (Table 2.3).
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