Intrusion-related gold occurrences in the Astaneh-Sarband area, west central Iran
The Astaneh-Sarband area is located in the Sanandaj-Sirjan metamorphic belt in west central Iran. The area hosts five intrusion-related tungsten and/or gold systems, including the Deh Hosein and Astaneh, gold occurrences and Nezam Abad tungsten-gold occurrence. The Astaneh-Sarband area contains Mesozoic schist, Late Cretaceous-Early Tertiary intrusive rocks and related contact metamorphic aureoles, and pegmatites. The Astaneh and Nezam Abad systems are hosted in granitic to grnaodioritic intrusive rocks of Early to Late Eocene age. At Deh Hosein, mineralization occurs, mainly in Jurassic-Triassic meta-sedimentary rocks which have undergone greenschist facies metamorphism and intrusion by the Astaneh granite-granodiorite complex. Gold occurs in quartz and quartz-sulfide veins and veinlets, and as disseminations. Major ore minerals are arsenopyrite, chalcopyrite, pyrrhotite, sphalerite, marcasite, bismite, native gold, and rare stannite. Adjacent to and within zones of intense quartz veining the predominant alteration assemblage is quartz + sericite + tourmaline + chlorite. The sulfide mineral content in the veins is generally less than 3 vol.%. The gold contents of samples from Deh Hosein, Astaneh and Nezam Abad range up to 9.5, 13.3, and 36.2 ppm respectively. Gold contents correlate moderately well with As, Bi, and Se. Arsenopyrite geothermometry, yields deposition temperatures of 580° to 380°C for these occurrences. Stable-isotope data include ´18O values of 11.5 to 19.2 (quartz), and δ34S values of −5.6 to 4 (galena, pyrite, arsenopyrite, chalcopyrite). The sulfur data are compatible with a magmatic fluid source. Lead isotope results are consistent with a lower crustal source for the ores at Deh Hosein.
KeywordsIntrusion-related gold Deh Hosein Iran
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- Farhadian MB (1991) Geochemical and mineralogical investigation into Nezam Abad tungsten deposit, Arak, Iran. Unpublished MSc thesis (in Persian), Tehran University, IranGoogle Scholar
- Hashemi M (2002) Probable gold mineralization associated with igneous body of Astaneh, Arak, Iran. Unpublished MSc thesis (in Persian), Teacher Training University of Tehran, IranGoogle Scholar
- Kretschmar U, Scott SD (1976) Phase relations involving arsenopyrite in the system Fe-As-S and their application. Can Mineral. 14:364–386Google Scholar
- Maddox LM, Bancroft GM, Scaini MJ, Lorimer JW (1998) Invisible gold: Comparison of Au deposition on pyrite and arsenopyrite. American Geologist. 83:1240–1245Google Scholar
- Masoudi F (1997) Contact metamorphism and pegmatite development in the region SW of Arak, Iran. PhD thesis. The University of Leeds, UKGoogle Scholar
- McCoy D, Newberry RJ, Layer P, DiMarchi JJ, Bakke A, Masterman DL (1997) Plutonic-related gold deposits of Interior Alaska. In: Goldfarb RJ, Miller LD (eds) Mineral Deposits of Alaska. Economic Geology Monography 9:191–241Google Scholar
- Momenzadeh M, Nezafati N, Pernicka E (2002) First indication of tin at the ancient mining site near Deh Hosein, West central Iran: a possible source for Luristan bronze, Abstract, 33rd International symposium on Archaeometry, Amsterdam, The NetherlandsGoogle Scholar
- Radfar J (1987) Petrology of granitic rocks from Astaneh area, Iran. Unpublished MSc thesis (in Persian). Tehran University, IranGoogle Scholar
- Sharp ZD, Essene EJ, Kelly WC (1985) A re-examination of the arsenopyrite geothermometer: pressure considerations and applications to natural assemblages. Can Mineral. 23:517–534Google Scholar