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| Titel: |
Stable isotope and fluid inclusion studies on the Mount Black lead-zinc deposit, southern New South Wales |
| Auteur: |
Ambler, E. P. Ashley, P. M. Both, R. A. Donnelly, T. H. |
| Verschenen in: |
Australian journal of earth sciences |
| Paginering: | Jaargang 26 (1979) nr. 7-8 pagina's 399-409 |
| Jaar: |
1979 |
| Inhoud: |
The Mount Black Pb-Zn deposit is a quartz-galena-sphalerite replacement body in the Silurian Cooleman Limestone. Fluid inclusion homogenisation temperatures range from 120° to 170°C for paragenetically early sphalerite, to 210° to 315°C for late quartz, and 245° to 320°C for calcite from contiguous recrystallised limestone. Fluid salinities increased with rising temperature, during deposition of the minerals, and the fluid composition changed from NaCl-rich to possibly CaCl2-NaCl (-?MgCl2)-rich brines. δ34S values of sphalerite and galena range from —8.1 to —2.7 per mil, and —13,5 to —4.4 per mil respectively. Although a magmatic source for sulphur is not excluded, it is suggested that most probably the sulphur was derived by biogenic reduction of sea-water sulphate during diagenesis. Carbon and oxygen isotope data for the Cooleman Limestone range from compositions typical of Silurian marine carbonate in samples distant from the deposit, to fluctuating, but 12C- and 16O-enriched in recrystallised material adjacent to the quartz-sulphide rocks. 12C-enrichment probably reflects organic carbon oxidation during karst formation, continuing later during limestone recrystallisation and accompanied by 16O-enrichment during the action of saline formation waters. The process of formation of the Mount Black deposit may have been analogous to that of Mississippi Valley-type deposits, but modified by and/or resulting from, an increasing geothermal gradient caused by nearby synchronous intrusions. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 11 van 14 gevonden artikelen
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