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Abstract
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Sediment-hosted disseminated gold deposits with high gold grade (> 1000 g/t) are known in the pyrite composition, that gold can be present as participating in chemical bounded (Au+ and Au+3) or nanoparticle inclusions (Au0) (e.g., Deditius et al., 2014). The Zarshuran gold deposit (155 t @ 2.63 g/t Au; Madan-Zamin Company, 2020) is situated 35 km north of Takab in the Takab-Angouran metallogenic district, NW Iran. According to Mehrabi et al. (1999) and Asadi et al. (2000), gold mineralization in the Zarshuran deposit is similar in many respects to the Carlin-style and Carlin-like gold deposits, respectively. Gold substitution has been reported to be below detection limit to a maximum of 0.64 wt.% and 3 wt.% in arsenian pyrite and arsenopyrite lattice, respectively (Voute et al., 2019). Here, we examine the relationship between geochemistry and textures of pyrite, with a view to constraining the mechanism of gold precipitation. We use electron probe microanalysis (EPMA) to study the composition of different pyrite types. The results show that the distribution of ferrous iron (Fe2+) is controlled by the initial diagenesis of Fe-C-S systems.
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