Sulfide δ34S composition of Palaeoproterozoic mineralisation in the Aileron Province, central Australia: an igneous sulfur source?

Abstract

Sulfide δ34S isotope values were obtained from 398 mineralised samples from 21 Palaeoproterozoic mineral deposits and prospects in the Aileron Province, central Australia. This work was carried out in order to understand the δ34S isotope characteristics of key deposits and prospects and to investigate the sulfur sources for a range of mineralisation styles. The δ34S values for mineralisation in Aileron Province range between -9 to +9 ‰, irrespective of mineralisation type. Near-zero average δ34S values for interpreted orthomagmatic and epigenetic (intrusion-related hydrothermal vein and skarn) deposits are consistent with mantle-derived sulfur. Metamorphosed sulfide mineralisation, which originally formed as (near) syngenetic volcanogenic, syn-sedimentary or carbonate-replacement deposits, also yield comparable near-zero δ34S values. Such δ34S signatures are typical of other Archean to Palaeoproterozoic volcanic- and sediment-hosted deposits that are interpreted to have formed in association with sulfate-poor seawater; they reflect the derivation of sulfur from igneous rocks, either directly from magmatic-hydrothermal fluids or indirectly from the leaching of volcanic rocks or intrusions. Sulfide-bearing igneous rocks (volcanic rocks and intrusions) are interpreted to be the major sulfur source for Palaeoproterozoic sulfide mineralisation found across the Aileron Province.