Lanark County (uraniferous pegmatites)
Ontario, Lanark County, Canada
UraniumU
- Type
- Uraninite-bearing pegmatite or alaskite (IAEA class 1.1)
Uranium ore sample from the Queen's University collection analysed by Voinot et al. (2024) for U, Mo and Tl; ε205Tl and δ238U decrease together in metamorphic and unconformity deposits (U reduction and Tl redox change), whereas δ97Mo is strongly modified by late remobilisation. Pristine uraninite of about 1000 Ma, lowest ε205Tl of the intrusive deposits (-9.1). Coordinates not published. Uvarova et al. (2014): δ238U (normalisation offset by about +0.60 ‰) and δ234U of samples from the Queen's University collection (Table 2).
δ238U in ‰ (per mil) Values of the same system
Standard : NBL CRM 112-A
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −0.31 ‰ | 1 | pristine uraninite with light brown alteration crust Single analysis; per-sample uncertainty not published; sample M9996; IAEA class 1.1. Anatectic: Pegmatite - alaskite (intrusive); average age used 1000 Ma; 55.48 % U, 2.7 µg/g Mo. | Voinot et al. (2024), Tl, Mo and U isotopes in U-ore deposits record Earth's fundamental … | |
| 0.29 ± 0.1 ‰ | 1 | uraninite Single analysis; ± 0.10 ‰ (2 SD, reproducibility); sample M9996, Lanark County, Ontario; bracketing-only δ238U at +0.25; 238U/235U of 137.876; about -0.31 ‰ after removing the 0.60 ‰ offset specific to this study; same sample as Voinot et al. (2024), published at -0.31 ‰; quartz-pebble conglomerate according to Uvarova et al. (2014), pegmatite according to Voinot et al. (2024). | Uvarova et al. (2014), Variations in the uranium isotopic compositions of uranium ores fr… |
δ234U in ‰ (per mil) Values of the same system
Standard : équilibre séculaire
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −6.14 ‰ | 1 | pristine uraninite with light brown alteration crust Single analysis; per-sample uncertainty not published; sample M9996; IAEA class 1.1. Anatectic: Pegmatite - alaskite (intrusive); average age used 1000 Ma; 55.48 % U, 2.7 µg/g Mo. | Voinot et al. (2024), Tl, Mo and U isotopes in U-ore deposits record Earth's fundamental … | |
| −4 ‰ | 1 | uraninite Single analysis; per-sample uncertainty not published; sample M9996, Lanark County, Ontario; Voinot et al. (2024) report -6.14 ‰ on the same sample; quartz-pebble conglomerate according to Uvarova et al. (2014), pegmatite according to Voinot et al. (2024). | Uvarova et al. (2014), Variations in the uranium isotopic compositions of uranium ores fr… |
ε205Tl in ε units (parts per 10,000) Values of the same system
Standard : NIST SRM 997
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −9.1 ± 0.8 ε | 1 | pristine uraninite with light brown alteration crust Single analysis; ± 0.8 (2 SD); sample M9996; IAEA class 1.1. Anatectic: Pegmatite - alaskite (intrusive); average age used 1000 Ma; 55.48 % U, 2.7 µg/g Mo. | Voinot et al. (2024), Tl, Mo and U isotopes in U-ore deposits record Earth's fundamental … |
δ97Mo in ‰ (per mil) Values of the same system
Standard : NIST SRM 3134
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 2.4 ± 0.17 ‰ | 1 | pristine uraninite with light brown alteration crust Single analysis; ± 0.17 (2 SD); sample M9996; IAEA class 1.1. Anatectic: Pegmatite - alaskite (intrusive); average age used 1000 Ma; 55.48 % U, 2.7 µg/g Mo. | Voinot et al. (2024), Tl, Mo and U isotopes in U-ore deposits record Earth's fundamental … |
Deposits of the same type
- Athabasca basin (unconformity uranium province) Canada
- Shea Creek (Athabasca) Canada
- Tim Mersoï basin (Arlit, Akouta, Imouraren) Niger
- Inkai (Chu-Sarysu basin) Kazakhstan
- Tulukuevskoye Russia
- Ty Gallen France
- Rophin France
- Key Lake (Deilmann and Gaertner) Canada
Cite this page
IsoFind Atlas (2026). Lanark County (uraniferous pegmatites), isotope signatures. https://www.isofind.tech/isotopes/en/deposits/comte-de-lanark-pegmatites-uraniferes/ (accessed 2026-10-16).
@misc{isofind2026lanarkcountyuraniferouspegmat,
title = {Lanark County (uraniferous pegmatites), isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/comte-de-lanark-pegmatites-uraniferes/},
note = {Accessed 2026-10-16}
}Updated : 2026-10-16