Darwin
California, Inyo County (40 miles west of Death Valley), United States
Carbonate replacementPb-Ag-Zn
- Type
- Intrusion-related massive replacement of calc-silicate limestones (CRD)
Massive replacement bodies in silicated Pennsylvanian and Permian limestones at the contact of a Jurassic quartz monzonite stock. Three zoned ore types: pyrite-sphalerite-galena, pyrrhotite-pyrite-magnetite-sphalerite-galena and Ag-Bi-Se galena. The rise in fluid pH (4.8 to 6.7) away from the intrusion controls zoning and ore deposition; fluids with over 20 % salts. Indicative coordinates.
δ34S in ‰ (per mil) Values of the same system
Standard : V-CDT
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 2.75 ± 0.81 ‰ | 1.64 / 4.38 ‰ | 16 | pyrite, pyrite ore (Defiance and Thompson-Essex) Mean and standard deviation recalculated from 16 samples, Table 1. First value kept for zoned samples. Published mean +2.8 ‰. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
| 1.97 ± 0.63 ‰ | 0.8 / 3.06 ‰ | 17 | sphalerite, pyrite ore (Defiance and Thompson-Essex) Mean and standard deviation recalculated from 17 samples, Table 1. First value kept for zoned sphalerite of sample 17 (2.65 to 3.11 ‰) and for 3509 and 3487 (methods A and B). Published mean +2.1 ‰. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
| 0.01 ± 0.54 ‰ | −0.91 / 0.88 ‰ | 13 | galena, pyrite ore (Defiance and Thompson-Essex) Mean and standard deviation recalculated from 13 samples, Table 1. Sphalerite-galena temperatures of 255 to 410 °C, reproducible within ± 30 °C. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
| −3.39 ‰ | 1 | pyrite, pyrrhotite ore (Thompson-Essex) One analysis (3494), Table 1. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… | |
| −2.23 ± 1.04 ‰ | −3.45 / −1.13 ‰ | 5 | sphalerite, pyrrhotite ore (Thompson-Essex) Mean and standard deviation recalculated from 5 samples, Table 1. Published mean -2.70 ‰ (including the second subsample of 3508). About 4 to 6 ‰ lighter than in the pyrite ore. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
| −4.17 ± 1.2 ‰ | −5.32 / −2.54 ‰ | 5 | galena, pyrrhotite ore (Thompson-Essex) Mean and standard deviation recalculated from 5 samples, Table 1. Published mean -4.42 ‰ (including the second subsample of 3508). | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
| −3.46 ± 0.12 ‰ | −3.6 / −3.31 ‰ | 4 | pyrrhotite, pyrrhotite ore (Thompson-Essex) Mean and standard deviation recalculated from 4 samples, Table 1. The minus sign of 3505 is missing in the table (printed 3.31); the published mean of -3.46 ‰ confirms -3.31. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
| −0.66 ± 0.05 ‰ | −0.69 / −0.62 ‰ | 2 | galena of the silver-bismuth-selenium ore Mean and standard deviation recalculated from 2 samples, Table 1. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
δ13C in ‰ (per mil) Values of the same system
Standard : V-PDB
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −4.92 ± 0.79 ‰ | −5.78 / −3.6 ‰ | 9 | rhombohedral post-sulfide calcite, pyrite ore (Defiance and Thompson-Essex) Mean and standard deviation recalculated from 9 samples, Table 3. Carbon is not in equilibrium with the host limestone (+0.7 to +2.5 ‰). | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
| −4.48 ± 1.45 ‰ | −5.55 / −2.4 ‰ | 4 | post-sulfide calcite, pyrrhotite ore (Thompson-Essex) Mean and standard deviation recalculated from 4 samples, Table 3. Carbon is not in equilibrium with the host limestone (+0.7 to +2.5 ‰). The abstract gives -5.8 to -3.6 ‰ for all calcites, which excludes the -2.40 ‰ value. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
| 1.62 ± 0.91 ‰ | 0.68 / 2.49 ‰ | 3 | relict limestone within the ore Mean and standard deviation recalculated from 3 samples, Table 3. Oxygen re-equilibrated with the fluids, well below Palaeozoic marine limestones (about +23 ‰). | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
δ18O in ‰ (per mil) Values of the same system
Standard : V-SMOW
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 12.78 ± 1.14 ‰ | 11.31 / 14.16 ‰ | 9 | rhombohedral post-sulfide calcite, pyrite ore (Defiance and Thompson-Essex) Mean and standard deviation recalculated from 9 samples, Table 3. Carbon is not in equilibrium with the host limestone (+0.7 to +2.5 ‰). | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
| 17.05 ± 1.44 ‰ | 15 / 18.36 ‰ | 4 | post-sulfide calcite, pyrrhotite ore (Thompson-Essex) Mean and standard deviation recalculated from 4 samples, Table 3. Carbon is not in equilibrium with the host limestone (+0.7 to +2.5 ‰). The abstract gives -5.8 to -3.6 ‰ for all calcites, which excludes the -2.40 ‰ value. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
| 17.24 ± 2.04 ‰ | 14.88 / 18.53 ‰ | 3 | relict limestone within the ore Mean and standard deviation recalculated from 3 samples, Table 3. Oxygen re-equilibrated with the fluids, well below Palaeozoic marine limestones (about +23 ‰). | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
| 5 ± 2.5 ‰ | fluid water calculated from calcite, pyrite ore (Defiance and Thompson-Essex) Value calculated (O'Neil et al., 1969) for 225 ± 25 °C, not measured directly. Interpret accordingly. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… | ||
| 9 ± 3 ‰ | fluid water calculated from calcite, pyrrhotite ore (Thompson-Essex) Value calculated (O'Neil et al., 1969) for 225 ± 25 °C, not measured directly. Interpret accordingly. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
δD in ‰ (per mil) Values of the same system
Standard : V-SMOW
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −66 ± 4 ‰ | −70 / −62 ‰ | 3 | fluid inclusion water in sphalerite (Defiance) Mean and standard deviation recalculated from 3 samples, Table 4. Brines with over 20 % salts, atomic K/Na 0.20 to 0.26. | Rye et al. (1974), Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-… |
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Cite this page
IsoFind Atlas (2026). Darwin, isotope signatures. https://www.isofind.tech/isotopes/en/deposits/darwin/ (accessed 2026-10-13).
@misc{isofind2026darwinisotopesignatures,
title = {Darwin, isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/darwin/},
note = {Accessed 2026-10-13}
}Updated : 2026-10-13