Zálesí
Olomouc Region, Rychlebské hory (Javorník), Czechia
UraniumU (Ni, Co, Ag, Bi)
- Type
- U-Ni-Co-As-Ag-Bi veins (five-element association)
Vein deposit of the Orlica-Śnieżnik crystalline complex (north-eastern margin of the Bohemian Massif), in paragneisses, mica schists, marbles and amphibolites of the Stronie Group thrust over the Śnieżnik orthogneisses; 30 quartz-carbonate veins 5 to 25 cm thick and two stockworks; over 400 t uranium mined from 1958 to 1968. Three post-Variscan stages: uraninite (chemical ages 232 to 135 Ma, median 161 Ma), arsenide, sulphide. Low-temperature (80 to 130 °C, locally lower) and low-pressure (below 100 bars) fluids: H2O-CaCl2-NaCl brines up to 27 wt% salts, with external Br/Cl and I/Cl, derived from Permian-Triassic evaporites of the Polish Basin, mixed with meteoric waters (δ18O about -4 ‰); sulphide-stage fluids at δ18O about -10 ‰, linked to Cenozoic reactivation according to the authors. Coordinates not given.
δ13C in ‰ (per mil) Values of the same system
Standard : V-PDB
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −4.08 ± 0.3 ‰ | −4.5 / −3.7 ‰ | 5 | uraninite-stage calcite Mean and standard deviation recalculated from 5 analyses, Za-1, Za-5, Za-12, Za-16 and Za-25; fluid δ13C (HCO3-) -6.6 to -5.7 ‰. | Dolníček et al. (2009), Origin of the Zálesí U–Ni–Co–As–Ag/Bi deposit, Bohemian Massif, C… |
| −8.5 ‰ | 1 | arsenide-stage calcite (Za-3) Single analysis; one of the two values below -4.8 ‰. | Dolníček et al. (2009), Origin of the Zálesí U–Ni–Co–As–Ag/Bi deposit, Bohemian Massif, C… | |
| −4.47 ± 0.36 ‰ | −4.8 / −4 ‰ | 4 | arsenide-stage dolomite Mean and standard deviation recalculated from 4 analyses, Za-8, Za-11, Za-13 and Za-15. | Dolníček et al. (2009), Origin of the Zálesí U–Ni–Co–As–Ag/Bi deposit, Bohemian Massif, C… |
| −7.73 ± 7.87 ‰ | −16.8 / −2.6 ‰ | 3 | sulphide-stage calcite Mean and standard deviation recalculated from 3 analyses, Za-2 at -16.8 ‰, the other low value of the study; fluid -21.4 to -4.5 ‰. | Dolníček et al. (2009), Origin of the Zálesí U–Ni–Co–As–Ag/Bi deposit, Bohemian Massif, C… |
δ18O in ‰ (per mil) Values of the same system
Standard : V-SMOW
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 15.56 ± 1.9 ‰ | 13.2 / 17.2 ‰ | 5 | uraninite-stage calcite Mean and standard deviation recalculated from 5 analyses, calculated fluid -7.3 to +4.5 ‰ (64 to 148 °C). | Dolníček et al. (2009), Origin of the Zálesí U–Ni–Co–As–Ag/Bi deposit, Bohemian Massif, C… |
| 13.5 ‰ | 1 | arsenide-stage calcite (Za-3) Single analysis; calculated fluid -3.7 to -1.0 ‰ (94 to 121 °C). | Dolníček et al. (2009), Origin of the Zálesí U–Ni–Co–As–Ag/Bi deposit, Bohemian Massif, C… | |
| 18.05 ± 1.11 ‰ | 16.4 / 18.8 ‰ | 4 | arsenide-stage dolomite Mean and standard deviation recalculated from 4 analyses. | Dolníček et al. (2009), Origin of the Zálesí U–Ni–Co–As–Ag/Bi deposit, Bohemian Massif, C… |
| 14.13 ± 0.96 ‰ | 13.1 / 15 ‰ | 3 | sulphide-stage calcite Mean and standard deviation recalculated from 3 analyses, calculated fluid -13.8 to +0.1 ‰ (30 to 124 °C). | Dolníček et al. (2009), Origin of the Zálesí U–Ni–Co–As–Ag/Bi deposit, Bohemian Massif, C… |
δ34S in ‰ (per mil) Values of the same system
Standard : V-CDT
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −3.01 ± 1.09 ‰ | −4.5 / −1.3 ‰ | 7 | uraninite-stage sulphides (chalcopyrite, sphalerite, bornite) Mean and standard deviation recalculated from 7 analyses, five chalcopyrites, one sphalerite (Za-6) and one bornite (Za-17); the text gives -1.2 to -4.5 ‰; non-equilibrated chalcopyrite-sphalerite pair (unrealistic 230 °C). | Dolníček et al. (2009), Origin of the Zálesí U–Ni–Co–As–Ag/Bi deposit, Bohemian Massif, C… |
| −12.05 ± 2.57 ‰ | −15.3 / −9.2 ‰ | 4 | sulphide-stage sulphides (sphalerite, pyrite, galena) Mean and standard deviation recalculated from 4 analyses, the text gives -9.2 to -15.4 ‰, the table -15.3 ‰ for pyrite Za-9. | Dolníček et al. (2009), Origin of the Zálesí U–Ni–Co–As–Ag/Bi deposit, Bohemian Massif, C… |
| −28.6 ‰ | 1 | host-rock pyrite (Za-3) Single analysis; the lowest value of the study. | Dolníček et al. (2009), Origin of the Zálesí U–Ni–Co–As–Ag/Bi deposit, Bohemian Massif, C… |
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). Zálesí, isotope signatures. https://www.isofind.tech/isotopes/en/deposits/zalesi/ (accessed 2026-10-14).
@misc{isofind2026zalesiisotopesignatures,
title = {Zálesí, isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/zalesi/},
note = {Accessed 2026-10-14}
}Updated : 2026-10-14