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

Blandine Gourcerol (1) , D J Kontak (2) , J A Petrus (2) , P C Thurston (2)

1 BRGM - Bureau de Recherches Géologiques et Minières
2 Laurentian University

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.

Mots clés: LA-ICP-MS; Metallogeny; Meguma Terrane; Gold; Orogenic deposit

Domaines: Géochimie; Pétrographie; Minéralogie; Géologie appliquée

Blandine Gourcerol, D J Kontak, J A Petrus, P C Thurston. Application of LA ICP-MS analysis of arsenopyrite to gold metallogeny of the Meguma Terrane, Nova Scotia, Canada. Gondwana Research, 2020, 81, pp.265-290. ⟨10.1016/j.gr.2019.11.011⟩. ⟨hal-02442027⟩