Key Lake (Deilmann and Gaertner)
Saskatchewan (south-eastern rim of the Athabasca Basin), Canada
UraniumU (Ni, Co)
- Type
- Unconformity-type uranium (Athabasca type)
Unconformity-type uranium deposit in a steeply dipping shear zone, traceable for about 5 km, that cuts the unconformity between the basement (Archaean granitoids, Aphebian garnet-graphite-biotite-cordierite gneisses) and the quartz sandstones of the Manitou Falls Formation (Athabasca Group, Helikian), with a palaeoregolith below the unconformity. Two ore bodies: Deilmann, concentrated at the unconformity with lenses up to 150 m into the gneisses, and Gaertner, in faulted and brecciated sandstone; combined reserves of 74,000 t U3O8 (Sibbald, 1985). Pitchblende and coffinite associated with Ni-Co sulpharsenides. U-Pb age of the uranium minerals 1350 Ma; illite K-Ar ages of 1131, 1187 and 1189 Ma. Mg chlorite of the altered basement equilibrated at about 200 °C with a fluid of δD near -20 ‰ and δ18O near +5 ‰, sandstone illite halo equilibrated at about 200 °C with a basinal brine (δD about -65 ‰, δ18O about +5 ‰): uranium concentrated by mixing of the two fluids at the unconformity according to the authors; quartz-illite pairs from the shear zone give 190-230 °C. Late kaolinite and recrystallised Fe-Mg chlorite (δD down to -172 ‰) formed with meteoric waters (δD -50 ± 30 ‰, δ18O -7 ± 3 ‰ at about 50 °C). Indicative coordinates (Key Lake mine).
δ18O in ‰ (per mil) Values of the same system
Standard : V-SMOW
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 9.2 ± 1.24 ‰ | 7.1 / 11.8 ‰ | 21 | kaolinite-free Mg chlorite and illite (< 2 µm fraction) of the altered gneiss, Deilmann ore body Mean and standard deviation recalculated from 21 analyses, basement alteration linked to the uranium, equilibrated at about 200 °C with a fluid near +5 ‰ δ18O according to the authors. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| 10.44 ± 2.1 ‰ | 7.6 / 13.2 ‰ | 5 | chlorite, illite and kaolinite (< 2 µm fraction) of altered gneiss from shear and ore zones, Deilmann ore body Mean and standard deviation recalculated from 5 analyses, samples 23, 157, 165, 172 and 177. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| 11.64 ± 1.34 ‰ | 9.2 / 13.3 ‰ | 12 | illite and Mg chlorite (< 2 µm fraction) of the palaeoregolith below the unconformity, Deilmann ore body Mean and standard deviation recalculated from 12 analyses. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| 8.29 ± 1.4 ‰ | 6.9 / 10.8 ‰ | 8 | chlorite and illite (< 2 µm fraction) of the altered gneiss, Gaertner ore body Mean and standard deviation recalculated from 8 analyses, samples 104, 105, 112, 113, 114H, 114W, 117 and 119 GP. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| 7.8 ‰ | 1 | fracture kaolinite in gneiss, Gaertner ore body (116GP) Single analysis. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… | |
| 10.5 ‰ | 1 | vein dravite, Gaertner ore body (118GP) Single analysis. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… | |
| 11.79 ± 1.21 ‰ | 10.3 / 13.8 ‰ | 7 | illite (< 2 µm fraction) of the illite halo in the Athabasca sandstone above the deposit Mean and standard deviation recalculated from 7 analyses, samples 27, 99, 100, 106GP, 80vs8/4, 80vs9/4 and 80vs51/4; includes unpublished data of Kyser and Hoeve (80vs samples); values not corrected for detrital quartz contamination; equilibrium at about 200 °C with a basinal brine (δ18O about +5 ‰) according to the authors. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| 14.42 ± 1.89 ‰ | 12.2 / 17.2 ‰ | 11 | kaolinite (< 2 µm fraction) of the kaolinite halo in the Athabasca sandstone Mean and standard deviation recalculated from 11 analyses, samples 14, 29, 30, 57, 58, 159, 162, 80vs54/4, 56/4, 57/4 and 137/4; includes unpublished data of Kyser and Hoeve (80vs samples); values not corrected for detrital quartz contamination. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| 12.11 ± 0.74 ‰ | 10.9 / 13.1 ‰ | 9 | chlorite (< 2 µm fraction) of the sandstone chlorite zone above the deposit Mean and standard deviation recalculated from 9 analyses, samples 122, 131, 150, 160, 170, 108GP, 109GP, 115GP and 134GP; values not corrected for detrital quartz contamination. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| 9.68 ± 2.26 ‰ | 7.3 / 12.2 ‰ | 5 | Fe-Mg chlorite and kaolinite (< 2 µm fraction) of the Gaertner ore matrix Mean and standard deviation recalculated from 5 analyses, samples 110GP, 111GP, 126GP, 136GP and 137GP. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
δD in ‰ (per mil) Values of the same system
Standard : V-SMOW
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −64.25 ± 7.03 ‰ | −77 / −55 ‰ | 8 | kaolinite-free Mg chlorite and illite (< 2 µm fraction) of the altered gneiss, Deilmann ore body Mean and standard deviation recalculated from 8 analyses, samples 6, 7, 8, 47, 48, 49, 153 and 175; fluid δD near -20 ‰ according to the authors. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| −117.75 ± 30.32 ‰ | −148 / −77 ‰ | 4 | chlorite, illite and kaolinite (< 2 µm fraction) of altered gneiss from shear and ore zones, Deilmann ore body Mean and standard deviation recalculated from 4 analyses, late kaolinite and recrystallised chlorite, formed with meteoric waters according to the authors. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| −73.9 ± 12.79 ‰ | −93 / −58 ‰ | 10 | illite and Mg chlorite (< 2 µm fraction) of the palaeoregolith below the unconformity, Deilmann ore body Mean and standard deviation recalculated from 10 analyses. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| −62.12 ± 3.98 ‰ | −70 / −58 ‰ | 8 | chlorite and illite (< 2 µm fraction) of the altered gneiss, Gaertner ore body Mean and standard deviation recalculated from 8 analyses. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| −119 ‰ | 1 | fracture kaolinite in gneiss, Gaertner ore body (116GP) Single analysis; late kaolinite of meteoric origin. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… | |
| −68 ‰ | 1 | vein dravite, Gaertner ore body (118GP) Single analysis. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… | |
| −70.8 ± 4.15 ‰ | −77 / −67 ‰ | 5 | illite (< 2 µm fraction) of the illite halo in the Athabasca sandstone above the deposit Mean and standard deviation recalculated from 5 analyses, includes unpublished data of Kyser and Hoeve (80vs samples); values not corrected for detrital quartz contamination; basinal brine δD about -65 ‰ according to the authors. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| −76.5 ± 26.74 ‰ | −119 / −46 ‰ | 8 | kaolinite (< 2 µm fraction) of the kaolinite halo in the Athabasca sandstone Mean and standard deviation recalculated from 8 analyses, includes unpublished data of Kyser and Hoeve (80vs samples); values not corrected for detrital quartz contamination. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| −102.11 ± 21.32 ‰ | −147 / −73 ‰ | 9 | chlorite (< 2 µm fraction) of the sandstone chlorite zone above the deposit Mean and standard deviation recalculated from 9 analyses. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
| −147.6 ± 25.66 ‰ | −172 / −116 ‰ | 5 | Fe-Mg chlorite and kaolinite (< 2 µm fraction) of the Gaertner ore matrix Mean and standard deviation recalculated from 5 analyses, hydrothermal chlorite recrystallised by the latest meteoric event, the lowest δD values of the deposit. | Wilson et Kyser (1987), Stable isotope geochemistry of alteration associated with the Key… |
Deposits of the same type
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- Rophin France
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- Inkai (Chu-Sarysu basin) Kazakhstan
- Tulukuevskoye Russia
Cite this page
IsoFind Atlas (2026). Key Lake (Deilmann and Gaertner), isotope signatures. https://www.isofind.tech/isotopes/en/deposits/key-lake-deilmann-et-gaertner/ (accessed 2026-10-14).
@misc{isofind2026keylakedeilmannandgaertneriso,
title = {Key Lake (Deilmann and Gaertner), isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/key-lake-deilmann-et-gaertner/},
note = {Accessed 2026-10-14}
}Updated : 2026-10-14