Rhenium Enrichment in the Muratdere Cu-Mo (Au-Re) Porphyry Deposit, Turkey: Evidence from Stable Isotope Analyses (δ34S, δ18O, δD) and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Analysis of Sulfides

Abstract

The Muratdere Cu-Mo (Au) porphyry deposit in western Turkey contains elevated levels of rhenium and is hosted within granodioritic intrusions into an ophiolitic mélange sequence in the Anatolian belt. The deposit contains several stages of mineralization: early microfracture-hosted molybdenite and chalcopyrite, followed by a quartz-pyrite-chalcopyrite vein set associated with Cu-Au grade, a quartz-chalcopyrite-pyrite-molybdenite vein set associated with Cu-Mo-Re grade, and a later polymetallic quartz-barite-sphalerite-galena-pyrite vein set. The rhenium in Muratdere is hosted within two generations of molybdenite: early microfracture-hosted molybdenite and later vein-hosted molybdenite. In situ laser ablation-inductively coupled plasma-mass spectrometry analysis of sulfides shows that the later molybdenite has significantly higher concentrations of Re (average 1,124 ppm, σ = 730 ppm, n = 43) than the early microfracture-hosted molybdenite (average 566 ppm, σ = 423 ppm, n = 28). Pyrite crystals associated with the Re-rich molybdenite have higher Co and As concentrations than those in other vein sets, with Au associated with As. The microfracture-hosted sulfides have δ34S values between −2.2‰ and +4.6‰, consistent with a magmatic source. The vein-hosted sulfides associated with the high-Re molybdenite have a δ34S signature of 5.6‰ to 8.8‰, similar to values found in peridotite lenses in the Anatolian belt. The later enrichment in Re and δ34S-enriched S may be sourced from the surrounding ophiolitic country rock or may be the result of changing redox conditions during deposit formation.

Metallogeny of the Tethyan Orogenic Belt: From Mesozoic Magmatic Arcs to Cenozoic Back-Arc and Postcollisional Settings in Southeast Europe, Anatolia, and the Lesser Caucasus: An Introduction

“…Porphyry deposits not only provide Cu, Mo, and Au to society, but they also are the predominant source of the world's Re production (McFall et al, 2019). The source and the mechanisms of the pronounced Re enrichment in porphyry deposits are still poorly understood.…”

“…The source and the mechanisms of the pronounced Re enrichment in porphyry deposits are still poorly understood. McFall et al (2019) have addressed this topic through a study on the postcollisional Muratdere porphyry Cu-Mo deposit of western Turkey (Fig. 1), which is characterized by a particularly high Re enrichment.…”

Metal-Selective Processing from the Los Sulfatos Porphyry-Type Deposit in Chile: Co, Au, and Re Recovery Workflows Based on Advanced Geochemical Characterization

“…Demand for these metals will increase in the coming years, with copper (Cu) being in greatest demand worldwide, estimated up to 40 times greater by 2100 [7]. This will be accompanied by other metals such as cobalt (Co), silver (Ag), tellurium (Te), rare earth elements (REEs), all of which are considered critical because of the risk they pose to supply [5,8]. Constraints on Cu supply focus on the expected decline in ore grades [9], which implies that significantly more mine material will have to be mined and processed to produce the same amount of metal.…”

“…This would allow the exploitation of all of the metal resources contained in a single mineral deposit, while at the same time minimizing the amount of waste generated [11]. contained in molybdenite (up to 4.7 wt.% Re), a common sulfide in porphyry-type deposits [8,13,25]. However, Re concentrations could not be assessed during operational geochemical characterization, because this procedure is performed on composite samples by whole-rock analysis.…”

Grain-scale distribution of molybdenite polytypes versus rhenium contents: μXRD and EBSD data

“…This makes the study of both structural and chemical heterogeneity of molybdenite extremely important. Heterogeneous distribution of rhenium, and, sometimes, tungsten and selenium in molybdenite have been identified by electron microprobe analysis (EMPA) (Kovalenker et al ., 1974; Prokof'ev et al ., 2007; Voudouris et al ., 2009, 2019; Grabezhev and Shagalov, 2010; Grabezhev, 2013; Grabezhev and Voudouris, 2013; Kalinin et al ., 2013; Maksimyuk and Kulikova, 2013; Grabezhev and Hiller, 2015; Plotinskaya et al ., 2015, 2018 a ; Rathkopf et al ., 2017; McFall et al ., 2019), by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) (Aleinikoff et al ., 2012; Ciobanu et al ., 2013; Bogdanov and Krumov, 2016; Kovalenker et al ., 2018, Plotinskaya et al ., 2018 a ), and by nanoscale secondary ion mass spectrometry (NanoSIMS) (Barra et al , 2017).…”