Publication Type:

Journal Article


Mineralium Deposita, Springer-Verlag, Berlin, Germany, Volume 46, Number 3, p.289-304 (2011)




Canada, eastern canada, folds, geochemistry, gold ores, intrusions, isotope ratios, Isotopes, Maritime Provinces, Meguma terrane, metal ores, Metallogeny, Metamorphic rocks, metasedimentary rocks, mineral deposits, genesis, Mineral exploration, modal analysis, Nova Scotia, O-18/O-16, orogenic belts, oxygen, Petrology, South Mountain Batholith, Stable isotopes, structural controls, tectonics, terranes, veins


Sampling of quartz vein material from two gold deposits of similar geological setting but different ages (The Ovens, 408 Ma; Dufferin, 380 Ma) in the Meguma Terrane of Nova Scotia has been done to compare and contrast their delta (super 18) O (sub quartz) signatures. Despite different ages of formation, quartz from all vein types in each of the deposits (i.e. saddle-reef, bedding-concordant leg reefs, en echelon, discordant) shows limited intra-deposit variation with similar average delta (super 18) O values of +15.2+ or -0.9 ppm (n=16) for The Ovens and +15.7+ or -0.6 ppm (n=12) for Dufferin. Using an average delta (super 18) O value of +15.4 ppm for the two deposits, the corresponding delta (super 18) O (sub H2O) values, calculated for 400 degrees C and 350 degrees C based on constraints from mineral assemblages and fluid inclusion studies, indicate averages of 11.4+ or -0.2 ppm and +10.2+ or -0.2 ppm, respectively. The isotopic data indicate that: (1) the vein-forming fluids have a metamorphic signature, (2) all vein types in the two deposits represent formation from a single, isotopically homogeneous fluid, and (3) a fluid of similar isotopic signature was generated by two contrasting tectono-thermal events in the Meguma Terrane that were separated by 30 Ma. Integration of these results with previously published data for 14 Meguma gold deposits indicate a general stratigraphic dependence in delta (super 18) O (sub H2O) values for deposits when arranged in their relative stratigraphic position such that delta (super 18) O (sub H2O) values increase upwards in the stratigraphy. This apparent trend cannot be explained by models involving either fluid mixing or cooling of the vein-forming fluids, but instead is modelled using fluid/rock interaction taking into account a change in the modal mineralogy of the metasedimentary rocks upwards in the stratigraphy. Copyright 2011 Springer-Verlag


GeoRef, Copyright 2018, American Geological Institute.<br/>2011-076687<br/>Dufferin Deposit<br/>The Ovens Deposit