Smith Ranch-Highland
Wyoming, Converse County, southern Powder River Basin, United States
UraniumU
- Type
- Sandstone-hosted roll-front uranium
Largest in situ recovery uranium mine in the United States (Cameco), average grade 0.10 % U3O8; ore fronts in three stacked arkosic sandstones of the Fort Union Formation (Palaeocene, upper 213 m of an over 305 m sequence), separated by mudstones and carbonate-rich beds; mineralisation about 3 Ma old (U-Pb). Core from an unmined area (Mine Unit 3, sampled in 2013): non-crystalline U(IV) bound to organic carbon or carbonate dominant (58 to 89 % of uranium), minor uraninite and U(VI); δ238U above the crustal value in three samples out of four: mainly biological U(VI) reduction according to Bhattacharyya et al. (2017). Coordinates not given.
δ238U in ‰ (per mil) Values of the same system
Standard : NBL CRM 112-A
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −0.12 ± 0.38 ‰ | −0.68 / 0.16 ‰ | 4 | mineralised arkosic sandstone of the roll front (whole rock, 191 to 198 m) Mean and standard deviation recalculated from 4 analyses, values read from Figure 3 (reading precision about ±0.02 ‰, Table S5 not provided): +0.09 ‰ at 191 m, +0.16 ‰ at 194 m, -0.68 ‰ at 196 m (the only value below the crust, U bound to Fe oxides, possible abiotic reduction) and -0.06 ‰ at 198 m; triplicate 2SD about 0.1 ‰. | Bhattacharyya et al. (2017), Biogenic non-crystalline U(IV) revealed as major component i… |
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Cite this page
IsoFind Atlas (2026). Smith Ranch-Highland, isotope signatures. https://www.isofind.tech/isotopes/en/deposits/smith-ranch-highland/ (accessed 2026-10-15).
@misc{isofind2026smithranchhighlandisotopesign,
title = {Smith Ranch-Highland, isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/smith-ranch-highland/},
note = {Accessed 2026-10-15}
}Updated : 2026-10-15