Stewart (Pala district)
San Diego County, California, United States
Magmatic (Ni-Cu-PGE, carbonatites)Li (lépidolite), gemmes
- Type
- Gem-pocket granitic pegmatite-aplite (LCT type)
Late Cretaceous (about 100 Ma) pegmatite-aplite dikes of the Southern California batholith, 1 to 3 m thick and gently dipping, with a basal aplite zone, a pocket zone (tourmaline, beryl, quartz) and graphic pegmatite. Crystallisation from 730-700 to 565 °C, pockets at 565-525 °C under about 2 kbar, nearly closed system. Group A dike in gabbro, with a lepidolite orebody; lepidolite dated at about 110 Ma (Rb-Sr). Indicative coordinates.
δ18O in ‰ (per mil) Values of the same system
Standard : V-SMOW
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 10.3 ± 1 ‰ | 8.7 / 10.93 ‰ | 4 | quartz Mean and standard deviation recalculated from 4 analyses, S-1 = mean of the six subsamples of the pocket crystal (Table 3, +10.6 to +11.1 ‰); S-5, quartz from the pink-tourmaline pocket zone, clearly lighter (+8.7 ‰). | Taylor et al. (1979), Stable isotope and fluid inclusion studies of gem-bearing granitic … |
δD in ‰ (per mil) Values of the same system
Standard : V-SMOW
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −87 ± 13 ‰ | −101 / −75 ‰ | 4 | lepidolite Mean and standard deviation recalculated from 4 analyses, graphic pegmatite, ore zone and pocket zone; lepidolite δ18O +8.2, +6.4 and +6.3 ‰. Pocket muscovite S-1: -82 ‰. | Taylor et al. (1979), Stable isotope and fluid inclusion studies of gem-bearing granitic … |
Deposits of the same type
- Tourmaline Queen (Pala district) United States
- Ocean View (Pala district) United States
- Himalaya (Mesa Grande district) United States
- Little Three (Ramona district) United States
- Stillwater Complex (J-M Reef) United States
- Magnet Cove alkaline complex United States
- Carolina tin-spodumene belt United States
- Sudbury Canada
Cite this page
IsoFind Atlas (2026). Stewart (Pala district), isotope signatures. https://www.isofind.tech/isotopes/en/deposits/stewart-district-de-pala/ (accessed 2026-10-13).
@misc{isofind2026stewartpaladistrictisotopesig,
title = {Stewart (Pala district), isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/stewart-district-de-pala/},
note = {Accessed 2026-10-13}
}Updated : 2026-10-13