An oxygen isotope study of two contrasting orogenic vein gold systems in the Meguma Terrane, Nova Scotia, Canada, with implications for fluid sources and genetic models

Carbon isotope studies of auriferous quartz carbonate veins from two orogenic gold deposits from the Neoarchean Chitradurga schist belt, Dharwar craton, India: Evidence for mantle/magmatic source of auriferous fluid

“…Comparative study of C and O isotopic composition of carbonates from the auriferous quartz veins and other carbonates in host rocks, the kind of study reported here, can provide stronger basis for deciphering the origin of the fluids with greater degree of confidence (Cf. Fairmaid et al, 2011;Kontak et al, 2011). In the present case, metamorphic devolatilization origin could be discounted and magmatic origin arrived on more firm basis.…”

Orogenic gold: Common or evolving fluid and metal sources through time

“…9). Furthermore, as noted above in the Paleozoic Meguma terrane (Kontak et al, 2011), a broad contact metamorphic event driven by magma emplacement can also lead to significant devolatilization and orogenic gold formation.…”

Application of LA ICP-MS analysis of arsenopyrite to gold metallogeny of the Meguma Terrane, Nova Scotia, Canada

“…Given the similar settings, vein paragenesis, and fluid chemistry, as constrained by isotopes (S, O, D, C), fluid inclusions (i.e., aqueous carbonic, X CO2 = 0.10-0.2, 5-10 wt% equiv. NaCl), and wall-rock al Kontak et al, 1990bKontak et al, , 1993Kontak and Smith, 1993;Kontak and Kerrich, 1995;Chen, 2015 Kontak et al, 1990bKontak et al, , 1993Bierlein and Smith, 2003;Chen, 2015 Cochrane Hill teration, these deposits have been suggested to share a metamorphic origin (e.g., Graves and Zentilli, 1982;Kontak et al, 1990aKontak et al, , 2011Kontak and Kerrich, 1997;Ryan and Smith, 1998;Kontak and Horne, 2010). However, direct dating (Re Os, 40 Ar/ 39 Ar) of some deposits indicate at least two distinct gold mineralizing events (see summary in Table 2): 1) an early one, coincident with regional deformation and recognized locally at Beaver Dam, The Ovens, and Touquoy deposits based on Re/Os dating of arsenopyrite grains (e.g., Morelli et al, 2005;Chen et al, 2014;Chen, 2015); and 2) a later event, which overlaps the felsic(−mafic) magmatism at ca.…”

“…The influence of the immediate wall rock to mineralized veins and, at a broader scale, the host stratigraphy on the geochemical signature of the mineralizing fluids has previously been discussed for the Meguma gold deposits based on extensive analysis of δ 34 S for sulfides, δ 13 C and 87 Sr/ 86 Sr for carbonates, δ 18 O for quartz and in-situ LA-ICP-MS trace-element chemistry of carbonates (Kontak and Smith, 1989;Sangster, 1992;Kerrich, 1995, 1997;Kontak and Jackson, 1999;Kontak et al, 2011). The δ 34 S values of sulfides from veins, wall rock and regional stratigraphy show a simi Fig.…”

“…408 Ma) and intrusion of large granitic batholiths (ca. 380 Ma) (Kontak and Horne, 2010;Kontak et al, 2011).Thus, despite the exhaustive amount of data available for these deposits (see further discussion below) there remain many outstanding questions about the elemental associations in these deposits, and the nature of both refractory and non-refractory gold in these systems. It is these aspects which are addressed in this paper.…”