Ingersoll Mine (Black Hills)
South Dakota, Black Hills (Keystone district), United States
UraniumU (pegmatite)
- Type
- Uraninite-bearing granitic pegmatite (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. Paleoproterozoic pegmatite uraninite (about 1600 Ma), highest δ97Mo of the study (+6.1 ‰) with very little Mo: Rayleigh scavenging of light Mo by U-rich phases (about 98 % of Mo removed). Indicative coordinates (Keystone). 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 |
|---|---|---|---|---|
| −0.42 ‰ | 1 | pegmatite uraninite Single analysis; per-sample uncertainty not published; sample M26947; IAEA class 1.1. Anatectic: Pegmatite - alaskite (intrusive); average age used 1600 Ma; 64.71 % U, 13.62 µg/g Tl, 0.1 µg/g Mo. | Voinot et al. (2024), Tl, Mo and U isotopes in U-ore deposits record Earth's fundamental … | |
| 0.19 ± 0.1 ‰ | 1 | uraninite Single analysis; ± 0.10 ‰ (2 SD, reproducibility); sample M26947, Ingersoll Mine, Keystone, Pennington County; bracketing-only δ238U at +0.11; 238U/235U of 137.862; about -0.41 ‰ after removing the 0.60 ‰ offset specific to this study; same sample as Voinot et al. (2024), published at -0.42 ‰. | 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 |
|---|---|---|---|---|
| −12.21 ‰ | 1 | pegmatite uraninite Single analysis; per-sample uncertainty not published; sample M26947; IAEA class 1.1. Anatectic: Pegmatite - alaskite (intrusive); average age used 1600 Ma; 64.71 % U, 13.62 µg/g Tl, 0.1 µg/g Mo. | Voinot et al. (2024), Tl, Mo and U isotopes in U-ore deposits record Earth's fundamental … | |
| −10 ‰ | 1 | uraninite Single analysis; per-sample uncertainty not published; sample M26947, Ingersoll Mine, Keystone, Pennington County; Voinot et al. (2024) report -12.21 ‰ on the same sample. | Uvarova et al. (2014), Variations in the uranium isotopic compositions of uranium ores fr… |
δ97Mo in ‰ (per mil) Values of the same system
Standard : NIST SRM 3134
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 6.1 ± 0.4 ‰ | 1 | pegmatite uraninite Single analysis; ± 0.4 (2 SD); sample M26947; IAEA class 1.1. Anatectic: Pegmatite - alaskite (intrusive); average age used 1600 Ma; 64.71 % U, 13.62 µg/g Tl, 0.1 µg/g Mo. | Voinot et al. (2024), Tl, Mo and U isotopes in U-ore deposits record Earth's fundamental … |
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Cite this page
IsoFind Atlas (2026). Ingersoll Mine (Black Hills), isotope signatures. https://www.isofind.tech/isotopes/en/deposits/mine-ingersoll-black-hills/ (accessed 2026-10-16).
@misc{isofind2026ingersollmineblackhillsisotop,
title = {Ingersoll Mine (Black Hills), isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/mine-ingersoll-black-hills/},
note = {Accessed 2026-10-16}
}Updated : 2026-10-16