Authors / CoAuthors
Mernagh, T.P. | Bastrakov, E.N.
Abstract
The concentration of sulfur in fluids associated orogenic gold deposits is important for understanding the transport of gold species but still remains poorly defined. In this study Raman spectroscopy has been used to obtain the concentrations and fugacities of H2S in individual fluid inclusions from the Archean, sub-amphibolite facies Missouri gold deposit in Western Australia. Type III, vapor-rich (XH2O < 0.4) fluid inclusions from the Missouri gold deposit were shown to contain highly variable CO2/CH4 ratios (0.01 to 1.9) and H2S fugacities of up to 1.6 MPa. The calculated values of H2S are consistent with the location of fluids within the general pyrite stability field next to the pyrite-pyrrhotite reaction boundary. This is in accord with the quartz(-plagioclase)-biotite-carbonate-pyrite alteration assemblage that occurs adjacent to the quartz veins at the Missouri deposit. Geochemical modelling was used to investigate how the concentration of H2S was affected by the fCO2/fCH4 ratio of a fluid in equilibrium with the pyrite-pyrrhotite alteration assemblage. Overall, the highest H2S concentrations are predicted for 'reduced-fluids' near the CH4 apex of the H2O-CH4-CO2 ternary diagram. Comparisons with the measured H2S concentrations show that the CH4-CO2¬-Pyrite-Troilite equilibrium could be the controlling factor on the H2S concentration of the fluid; other processes could have affected some inclusions which contain higher than predicted H2S concentrations. These are mostly restricted to the population of water-poor (XH2O < 0.1), essentially CH4-CO2 inclusions.
Product Type
nonGeographicDataset
eCat Id
73132
Contact for the resource
Custodian
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
-
- External PublicationScientific Journal Paper
- ( Theme )
-
- economic geology
- ( Theme )
-
- geochemistry
- Australian and New Zealand Standard Research Classification (ANZSRC)
-
- Earth Sciences
-
- Published_Internal
Publication Date
2013-01-01T00:00:00
Creation Date
Security Constraints
Legal Constraints
Status
Purpose
Maintenance Information
unknown
Topic Category
geoscientificInformation
Series Information
Lineage
Unknown
Parent Information
Extents
Reference System
Spatial Resolution
Service Information
Associations
Downloads and Links
Source Information
Source data not available.