The Light Stable Isotope (Hydrogen, Boron, Carbon, Nitrogen, Oxygen, Silicon, Sulfur) Composition of Orogenic Gold Deposits

Abstract Orogenic gold deposits formed in various terranes of most ages since the Paleoarchean and generally consist quartz veins hosted shear zones at ductile brittle transition under greenschist to lower amphibolite metamorphic conditions. Vein mineralogy is dominated by with amounts silicates, carbonates, phyllosilicates, borates, tungstates, sulfides, oxides. The isotopic composition these minerals fluid inclusions has been investigated 1960s constrain characteristics orogenic systems involved formation worldwide. This review based on 8580 stable isotope analyses, including δ 18 O, δD, 13 C, 34 S 15 N, 11 B, 30 Si values, from 5478 samples 558 reported literature 1960 2010. contribution describes variability light as function minerals, age deposits, their regional setting, country rocks. temperature equilibrium estimated mineral pairs for oxygen sulfur isotopes. Based temperatures, fractionation between components (H 2 CO H S), fluids better main parameters shared auriferous systems. display similar features through time, suggesting that conditions sources leading did not change significantly Archean Cenozoic. No consistent secular variations (−8.1‰ ≤ O 33‰, n = 4011), hydrogen (−187‰ δD −4‰, 246), carbon (−26.7‰ C 12.3‰, 1179), boron (−21.6‰ B 9‰, 119), silicon (−0.5‰ 0.8‰, 33) are documented. Only nitrogen (1.6‰ N 23.7‰, 258) sulfide sedimentary rocks (−27.2‰ 25‰, 717) variations. For nitrogen, interpreted record variation values sediments devolatilized during metamorphism. sulfur, reflect incorporation local ultimate seawater origin. significant vein documented different ages. Quartz-silicate, quartz-carbonate sulfide-sulfide temperatures 360 ± 76 °C (1σ; 332), agreement more common facies hostrocks inclusion microthermometry. Fluid complex but (hydrogen, boron, carbon, oxygen, sulfur) contributions released devolatilization igneous, volcano-sedimentary and/or magmatic water exsolved magma crystallization a necessary component, even if permissible specific cases. Isotopic data arrays can be result mixing high T (~550 °C)—high (~10‰)—low (~−60‰) deep-seated (metamorphic) reservoir low (~200 °C)—low (~2‰)—high (~0‰) upper crustal number deposits. origin likely sea- or meteoric filling host rock porosity, long history water–rock exchange. Mixing also explains large tourmaline veins. Regional spatial compositions reservoirs districts. case Val-d’Or (Abitibi), Coolgardie Kalgoorlie (Yilgarn) where end-member 4‰ compared Timmins, Larder Lake, Kirkland Lake districts (Abitibi). However, both trends converge towards common, end-member. Such cannot related buffering site deposition suggest provinciality source. mainly recorded Mesozoic Cenozoic micas systematically trapped same vein. suggests late involvement unrelated deposit formation. Yet, mica may infiltration Isotope exchange mineralizing Large (> 10‰) scale evolving redox reaction Deposits show shift higher fluid/rock