Sulfur isotope characteristics of the Permian VHMS deposits in Tasik Chini district, Central Belt of Peninsular Malaysia

Abstract

Sulfur isotope data from sulfide and sulfate minerals have been measured from the two typical examples of the Permian volcanic-hosted massive sulfide (VHMS) deposits at the Tasik Chini district in the Central Belt of Peninsular Malaysia. In this study, we present the sulfur isotope data for 33 sulfide minerals and 23 barite samples from two VHMS deposits in the Tasik Chini district. Sulfides show a narrow range of sulfur values from -2.9‰ to +8.30‰, which can be interpreted to be derived from a mixed sulfur source of reduced seawater sulfate with the possible addition of magmatic sulfur. Sulfate sulfur in barites yields a δ 34 S range between 11‰ and 22‰, which is comparable to that of Permian seawater sulfate. Sulfur isotope results obtained for the VHMS deposits in the Tasik Chini district suggest that the source of ore fluids during the formation of the Tasik Chini VHMS deposit is a seawater-dominated fluid with probably minor magmatic fluid input. This is similar to VHMS associated with ancient and modern submarine hydrothermal systems.

Geochemistry of Sphalerite from the Permian Volcanic-Hosted Massive Sulphide (VHMS) Deposits in the Tasik Chini Area, Peninsular Malaysia: Constraints for Ore Genesis

“…Therefore, the relatively lower FeS contents of sphalerite in the massive sulphide at both deposits suggest high sulphidation conditions and lower temperatures of formation, whereas higher FeS contents of sphalerite in the stringer sulphide can be related to the higher temperature conditions at the Tasik Chini deposit. This suggestion is also supported by a similar pattern of sulphur isotopes at both the deposits, which display an increase of δ 34 S value from the stringer zone to the massive sulphide through to barite mineralisations [42].…”

“…The Lebir Fault Zone is a suture zone marking the closed back-arc basin developed on the margin of the Permian East Malaya volcanic arc between the Central and Eastern Belts [33,41]. Based on geochemical, geochronological, Pb, and S isotopic characteristics and fluid inclusions data of the Permian VHMS deposits in the Tasik Chini area, the formation could have accompanied this back-arc basin evolution (e.g., [33,38,[42][43][44][45]).…”

“…This result strongly suggests that the mixing of sulphur and metal carrying fluids was a crucial process for ore formation in the Tasik Chini VHMS deposits. The mixing of different fluids (seawater dominant and minor magmatic fluids), based on the S, Pb isotopes of sulphide minerals and pyrite chemistry data, is considered responsible for controlling the chemistry of the sphalerite at both the Bukit Botol and Bukit Ketaya deposits [42][43][44], similar to the Eskay Creek VHMS deposit, Canada, as was suggested by [63]. Furthermore, the complex relationship of Zn/Cd ratios in sphalerite between the Bukit Botol and Bukit Ketaya deposits is also interpreted probably due to the differences in temperature, pH, salinity, pressure, and aFeS (average FeS content) contributions during their deposition as reported in other similar deposits (e.g., [13]).…”