Chang, Zhaoshan, Large, Ross R., and Maslennikov, Valery (2009) S-isotopes in sediment-hosted orogenic gold deposits: evidence for an early timing and a seawater sulfur source. In: Proceedings of the 10th Biennial Meeting of the the SGA 2009 (1) pp. 350-352. From: 10th Biennial Meeting of the SGA 2009, 17-20 August 2009, Townsville, QLD, Australia.

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Abstract

We report S isotopic compositions of sulfides of various paragenetic stages in the giant Sukhoi Log sediment-hosted orogenic Au deposit. The overall mean value and the significant variability in early pyrite indicates that the sulfur was from the reduction of seawater sulfate. The later generations of sulfide have δ34S values in successively smaller ranges, coincident with the mode that is around the median value of the whole data set. Together with textural evidence, sulfide trace element data, and gold occurrence, the data demonstrate that metamorphism has gradually homogenized the early sulfur, accompanied by the segregation of quartz and the release of Au from the lattice of early pyrite and its re-precipitation as inclusions in later pyrite. The S isotopic compositions of sulfides in Sukhoi Log, and many other major orogenic Au deposits hosted in sedimentary rocks of various ages, show a pattern generally parallel to the seawater sulfate curve through geologic time, indicating that the sulfur in most sediment-hosted orogenic Au deposits was probably also originally from the reduction of seawater sulfate. We conclude that sulfidation and gold mineralization in many sediment-hosted orogenic gold deposits was early during basin evolution when seawater was the principal active fluid, rather than later during or post basin inversion as proposed in current models.

Item ID:	26291
Item Type:	Conference Item (Abstract / Summary)
ISBN:	978-0-9805586-8-5
Keywords:	sediment-hosted orogenic Au deposits; S isotopes; sea water sulfate curve; Sukhoi Log; source of sulfur
Related URLs:	http://eprints.jcu.edu.au/26283/
Date Deposited:	12 Jun 2013 00:14
FoR Codes:	04 EARTH SCIENCES > 0403 Geology > 040307 Ore Deposit Petrology @ 50% 04 EARTH SCIENCES > 0402 Geochemistry > 040203 Isotope Geochemistry @ 50%
SEO Codes:	84 MINERAL RESOURCES (excl. Energy Resources) > 8401 Mineral Exploration > 840105 Precious (Noble) Metal Ore Exploration @ 100%
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