| Title | Fluid sources in basement-hosted unconformity-uranium ore systems: insights from tourmaline chemistry from deposits of the Patterson Lake corridor, Canada |
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| Author | Potter, E G ;
Kelly, C J; Davis, W J; Chi, G; Jiang, S -Y; Rabiei, M; McEwan, B J |
| Source | Geochemistry: Exploration, Environment, Analysis vol. 22, 2022 p. 1-25, https://doi.org/10.1144/geochem2021-037 |
| Image |  |
| Year | 2022 |
| Alt Series | Natural Resources Canada, Contribution Series 20210473 |
| Publisher | GEEA |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Saskatchewan |
| NTS | 74F/09; 74F/10; 74F/11; 74F/12; 74F/13; 74F/14; 74F/15; 74F/16 |
| Lat/Long WENS | -110.0000 -108.0000 58.0000 57.5000 |
| Subjects | geochemistry; boron; isotopes; tourmaline; uranium; unconformities; unconformity-type deposit; Athabasca Basin; Patterson Lake Formation |
| Illustrations | location maps; geological sketch maps; cross-sections; photographs; photomicrographs; ternary diagrams; plots; tables; graphs |
| Program | Targeted Geoscience Initiative (TGI-6) Digital Geoscience and Method Development Project |
| Released | 2022 02 03 |
| Abstract | The Patterson Lake corridor is a new uranium district located on the southwestern margin of the Athabasca Basin. Known resources extend almost 1 km below the unconformity in graphite- and
sulfide-bearing shear zones within highly altered metamorphic rocks. Despite different host rocks and greater depths below the unconformity, alteration assemblages (chlorite, illite, kaolinite, tourmaline and hematite), ore grades and textures are
typical of unconformity-related deposits. This alteration includes at least three generations of Mg-rich tourmaline (magnesio-foitite). The boron isotopic composition of magnesio-foitite varies with generation: the earliest generation, which is only
observed in shallow samples from the Triple R deposit (Tur 1), contain the heaviest isotopic signature (d11B = 19-26per mil), whereas subsequent generations (Tur 2 and Tur 3) yield lighter and more homogeneous isotopic signatures (d11B = 17.5-19.9
per mil). These results are consistent with precipitation from lowtemperature, NaCl- and CaCl2-rich brine(s) derived from an isotopically heavy boron source (e.g. evaporated seawater) that interacted with tourmaline and silicates in the basement
rocks and/or fluids derived from depth (with low d11B values). The lower d11B values in paragenetically later magnesio-foitite reflect greater contributions of basement-derived boron over time, whereas minor compositional variations reflect local
metal sources (e.g. Cr, V, Ti) and evolving fluid chemistry (decreasing Na and Ca, increasing Mg) over time. The d11B and chemical variation in magnesio-foitite over time reinforce the strong interactions with basement rocks in these systems while
supporting incursion of basinal brines well below the unconformity contact. |
| Summary | (Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI) is a collaborative federal geoscience program that provides industry with the next generation of geoscience
knowledge and innovative techniques to better detect buried mineral deposits, thereby reducing some of the risks of exploration. This contribution uses the boron isotopic composition of the alteration mineral tourmaline to unravel the fluid sources
and pathways in the Patterson Lake corridor uranium deposits. These isotopic signatures further support classification of the deposits as unconformity-related. |
| GEOSCAN ID | 329337 |
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