The critical role of magma degassing in sulphide melt mobility and metal enrichment

Giada Iacono-Marziano (1, 2) , Margaux Le Vaillant (3) , Belinda Godel (3) , Stephen Barnes (3) , Laurent Arbaret (1, 2)

1 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327
2 Magma - UMR7327
3 CSIRO Mineral Ressources Kensington

Abstract Much of the world’s supply of battery metals and platinum group elements (PGE) comes from sulphide ore bodies formed in ancient sub-volcanic magma plumbing systems. Research on magmatic sulphide ore genesis mainly focuses on sulphide melt-silicate melt equilibria. However, over the past few years, increasing evidence of the role of volatiles in magmatic sulphide ore systems has come to light. High temperature-high pressure experiments presented here reveal how the association between sulphide melt and a fluid phase may facilitate the coalescence of sulphide droplets and upgrade the metal content of the sulphide melt. We propose that the occurrence of a fluid phase in the magma can favour both accumulation and metal enrichment of a sulphide melt segregated from this magma, independent of the process producing the fluid phase. Here we show how sulphide-fluid associations preserved in the world-class Noril’sk-Talnakh ore deposits, in Polar Siberia, record the processes demonstrated experimentally.

Domaines: Planète et Univers [physics]; Sciences de la Terre

Giada Iacono-Marziano, Margaux Le Vaillant, Belinda Godel, Stephen Barnes, Laurent Arbaret. The critical role of magma degassing in sulphide melt mobility and metal enrichment. Nature Communications, 2022, 13 (1), pp.2359. ⟨10.1038/s41467-022-30107-y⟩. ⟨insu-03675531⟩