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

Abstract

Investigation of gold metallogeny in the Paleozoic Meguma terrane (Canada) is conducted through LA-ICP-MS analysis of arsenopyrite collected from eight slate-belt style vein gold deposits using a novel approach integrating elemental distribution maps and their derived elemental paragenesis with multi-element binary plots. The data reveal two distinct gold events: 1) an early event characterized by a Co-Ni-Mo-Sb-Se elemental association related to initial growth of arsenopyrite that reflects the presence of invisible gold (>10 ppm); and 2) a second event, spatially associated with late fracture sets, that is characterized by an Al-Ti-V-Mn element association and reflects either remobilization or upgrading of primary invisible gold and is manifest as visible gold.The results of this study indicate a complex and protracted history of gold mineralization which has important ramifications for the Meguma gold deposits, as well as other orogenic gold districts globally. In the case of the Meguma Terrane, it involves an initial gold event that is followed by element mobilization and, in the case of precious metals (Au, Ag), an upgrading through a zone refining process. In addition, the variable coupling and decoupling of elements is only revealed using in-situ derived LA-ICP-MS data.

Typomorphic Characteristics of Gold-Bearing Pyrite and Its Genetic Implications for the Fang’an Gold Deposit, the Bengbu Uplift, Eastern China

“…Gourcerol (2018) reported that the Au versus Ag plot is used to track Au mineralization and hydrothermal events [43]. The hydrothermal event has up to 100 ppm Au present in the sulfides, likely as invisible Au or nanoparticles [44]. The subsequent hydrothermal events are recorded by an upgrading due to the zone refining of the early Au, with it either having a similar Au/Ag ratio or a much higher one.…”

Antimony in quartz as a vector to mineralization: A statistical approach from five Variscan Sb occurrences (France)

“…Even if preliminary observations may not be conclusive as to the presence of Sb mineralization, reproducible concentrations of more than 10 ppm Sb in quartz are likely to signify that a vein network has very elevated potential for Sb mineralization in the immediate proximity. Much in the same way as LA-ICP-MS analyses of pyrite and arsenopyrite can help targeting potential Au deposit (e.g., Morey et al, 2008;Cook et al, 2013;Velasquez et al, 2014;Traore et al, 2016;Gourcerol et al, 2018Gourcerol et al, , 2020Zhang et al, 2020), our approach may help tracking Sb mineralization and improve prospecting during mineral exploration.…”

Structural and geochemical ore-forming processes in deformed gold deposits: towards a multiscale and multimethod approach

“…In a given deposit, sulphide mineral texture and geochemical signature may thus indicate gold input and crystallisation-remobilisation stages (e.g. Velasquez et al, 2014;Fougerouse et al, 2017;Pearce et al, 2018;Gourcerol et al, 2018aGourcerol et al, , 2018bGourcerol et al, , 2020Kontak et al, 2018;Large and Maslennikov, 2020;Combes et al, 2021) and could be used as pathfinders for high-grade gold ore (e.g. Kadel-Harder et al, 2020).…”

“…This approach has been widely used to study sulphide trace element geochemistry within individual deposits (e.g. Large et al, 2007Large et al, , 2009Cook et al, 2013;Hazarika et al, 2013;Velasquez et al, 2014;Gourcerol et al, 2018aGourcerol et al, , 2018bGourcerol et al, , 2020Augustin and Gaboury, 2019;Li et al, 2019;Wu et al, 2019a;Kadel-Harder et al, 2020;Combes et al, 2021). When coupled to the microstructural and -textural characterisation of ore-bearing mineral assemblages, such geochemical datasets allow to reassess ore genetic models (e.g.…”

“…When coupled to the microstructural and -textural characterisation of ore-bearing mineral assemblages, such geochemical datasets allow to reassess ore genetic models (e.g. Velasquez et al, 2014;Gourcerol et al, 2018aGourcerol et al, , 2020Pearce et al, 2018) and integrate micro-deformation-induced geochemical ore-forming processes into the deposit-and district-scale deformation history (e.g. Dubosq et al, 2018;Sayab et al, 2020).…”