Dataset for: Auriferous fluid evolution and the role of carbonaceous matter in a saddle-reef Au deposit: Dufferin deposit, Meguma terrane, Nova Scotia, Canada
- Description:
- Supplemental data tables containing microthermometric, Raman spectroscopic, and fluid inclusion laser ablation ICP-MS data collected in a study of the economic, metasedimentary rock-hosted Dufferin gold deposit.
Notes: SCIENTIFIC ABSTRACT The metaflysch-hosted, ~380 Ma Dufferin gold deposit, Meguma terrane, northeastern Appalachian Orogen (Nova Scotia, Canada) is an orogenic gold deposit with mineralized saddle reef-type quartz veins hosted by metasandstones and black slates in a tightly folded anticline. Together with native gold inclusions, genetically-related carbonaceous material (CM) in the veins occurs as pyrobitumen lining cavities and along fractures/grain boundaries proximal to vein contacts or wallrock fragments. Integrating microanalytical methods we document the precipitation of gold through coupled fluid-fO2 reduction (via interaction with CM) and pH increase. This destabilized gold bisulfide complexes leading to efficient Au precipitation from a gold-undersaturated (0.045 ± 0.024 ppm Au; 1σ; n=58) aqueous-carbonic fluid (H2O-NaCl-CO2, N2, CH4). The proposed mineralization mechanism is supported by: (i) a decrease in Au and redox-sensitive semimetals (As, Sb), and increase in wall rock-inherited elements (i.e., Mg, K, Ca, Sr, Fe) in fluid inclusions with time; (ii) a corresponding decrease in the XCO2 consistent with CO2 removal via reduction/respeciation and late carbonate precipitation; and (iii) gold embedding in, or on, the surface of CM inside mineralized cavities and fractures. Despite mineralizing fluids only transporting low concentrations of Au, far from saturation, they produced Meguma-type deposits indicating that the efficiency of Au precipitation from these fluids was high, a process promoted by the presence of CM. This work re-emphasizes CM as a potential prerequisite for efficient gold precipitation within the overall genetic model for similar orogenic metasedimentary settings globally where the presence and/or role of CM has been documented. - Kerr, Mitchell
- Contributor(s):
- Kerr, Mitchell
- Dépôt source:
- Saint Mary's University Dataverse
- Éditeur(s):
- Borealis
- Accès:
- Public
- URL:
- https://doi.org/10.5683/SP3/JIZXXK
- Date de publication:
- 2024-06-04
- Sujets (en):
- Mots-clés (en):
- Identificateur:
- https://doi.org/10.5683/SP3/JIZXXK
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