Gold and trace elements distribution in pyrite from the Senjedeh gold deposit Muteh mining district, according to EPMA results
Subject Areas :Zahra Nourian 1 , Mohammad yazdi 2 , Fariborz Masoudi 3
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Keywords: EPMA Pyrite Gold Senjedeh Muteh,
Abstract :
Muteh district is located in the central part of Sanandaj- Sirjan Zone. It consists of two active mines, including the Chah Khatoon and Senjedeh open pits. Exposed rock units in the area underwent greenschist to lower amphibolite metamorphism. They consist of deformed and metamorphosed volcano-sedimentary and acidic volcanic rocks. Gold mineralization is hosted in metamorphic rocks and pyrite is the most important Au-hosting mineral in the Muteh minig district; therefore, pyrite from the Senjedeh gold deposit was investigated using a combination of ore microscopy, including back-scattered imaging (BSE), and electron probe microanalysis (EPMA) with the aim to investigate gold and trace elements (Se, As, Pb, Bi, Sb, Co, Ag, Te, Zn, Cu, Ni) distribution. Based on our studies, there are two generations of pyrite: medium-grained, anhedral and deformed of first generation of pyrite that is characterized by abundance of microfractures, contains high level of gold ( up to 810 ppm) and coarse grained, euhedral of second generation of pyrite, contains low- medium level of gold (bdl- 110 ppm). Results of this study show that there are no systematic differences between the trace element compositions of two generations of pyrite. According to BSE, visible gold is widespread and present as irregular grains of native gold mostly along grain boundaries or filling microfractures of first generation of pyrite. Element mapping indicates that Co is incorporated in pyrite crystal lattice and shows compositional zoning in pyrite grains. Ultramafic, and to a lesser extent, mafic rocks are typically strongly enriched in Co; in contrast, felsic rocks usually contain low Co concentrations. Therefore, high Co concentrations should be a good indicator of a high proportion of mafic to ultramafic over felsic rocks in the fluid source area. Co concentrations in pyrite ,possibly linked to mafic/ultramafic metamorphic rocks, provide further evidence for the orogenic gold deposit affinity.
-حسنی، ح.، محجل، م.، 1378. تحلیل ساختاری و مدل تکتونیکی معدن طلای موته و ارتباط کانی‌سازی با آن. هجدهمین گردهمایی علوم زمین، سازمان زمین شناسی و اکتشافات معدنی
-رشید نژاد عمران، ن.، 1381. پترولوژی و ژئوشیمی سنگ‌های متاولکانو-سدیمنتری و پلوتونیک منطقه موته (جنوب دلیجان) با نگرشی بر خاستگاه و کانی سازی طلا. رساله دکتری، دانشکده علوم پایه، دانشگاه تربیت مدرس، 404.
-صدیق، م.، 1378. تحلیل ساختاری سنگ‌های دگرگونه در ناحیه موته، پایان‌نامه کارشناسی ارشد، دانشکده علوم پایه، دانشگاه تربیت مدرس، 93.
-کوهستانی، ح.، 1383. زمین شناسی، کانی شناسی و فابریک کانه‌زایی طلا در پهنه‌های برشی ناحیه چاه باغ در منطقه موته (جنوبغرب دلیجان، استان اصفهان). پایان نامه کارشناسی ارشد، دانشکده علوم پایه، دانشگاه تربیت مدرس، 228.
-Alavi, M., 1994. Tectonics of the Zagros orogenic belt of Iran: new data and interpretations. Tectonophysics, 229, 211–238.
-Ciobanu, C.L., Cook, N.J., and Pring, A., 2005. Bismuth tellurides as gold scavengers. Mineralium Deposita, 13, 1383–1386.
-Cook, N.J., and Chryssoulis, S.L., 1990. Concentrations of “invisible gold” in the common sulphides. Canadian Mineralogist, 28, 1–16.
-Cook, N.J., Ciobanu, C.L. and Mao, J.W., 2009. Textural control on gold distribution in As-free pyrite from the Dongping, Huangtuliang and Hougou gold deposits, North China Craton, (Hebei Province, China). Chemical Geology, 264, 101–121.
-Cook, N.J., Ciobanu, C.L., Meria, D., Silcock, D. and Wade, B., 2013. Arsenopyrite-Pyrite Association in an Orogenic Gold Ore: Tracing Mineralization History from Textures and Trace Elements. Economic Geology, 108, 1273–1283.
-Koglin, N., Frimmel, H.E., Minter, W.E.L. and Brätz, H., 2010. Trace-element characteristics of different pyrite types in Mesoarchaean to Palaeoproterozoic placer deposits. Mineralium Deposita, 45, 259–280.
-Kouhestani, H., Rashidnejad-Omran, N., Rastad, E., Mohajjel, M., Goldfarb, R.J., and Ghaderi, M., 2014. Orogenic gold mineralization at the Chah Bagh deposit, Muteh gold district, Iran. Journal of Asian Earth Sciences, 91, 89–106.
-Large, R.R., Danyushevsky, L., Hollit, C., Maslennikov, V., Meffre, S., Gilbert, S., Bull, S., Scott, R., Emsbo, P., Thomas, H., Singh, B. and Foster, J., 2009. Gold and trace element zonation in pyrite using a laser imaging technique: implications for the timing of gold in Orogenic and Carlin-style sediment-hosted deposits. Economic Geology, 104, 635–668.
-Masoudy, F., 1997. Contact Metamorphism and Pegmatite Development in the Region SW of Arak, Iran, Ph.D. thesis, University of Leeds, UK.
-Mohajjel, M., Fergusson, C.L. and Sahandi, M. R., 2003. Cretaceous–Tertiary convergence and continental collision Sanandaj–Sirjan Zone, western Iran. Journal of Asian Earth Sciences, 21, 397–412.
-Moritz, R., Ghazban, F. and Singer, B.S., 2006. Eocene gold ore formation at Muteh, Sanandaj-Sirjan tectonic zone, Western Iran: a result of late-stage extension and exhumation of metamorphic basement rocks within the Zagros Orogen. Economic Geology, 101, 1497–1524.
-Morse, J.W. and Luther, G.W., 1999. Chemical influences on trace metal-sulphide interactions in anoxic sediments. Geochimica et Cosmochimica. Acta, 63, 3373–3378.
-Nourian Ramsheh, Z., Mao, J., Yazdi, M., Xiang, J., Rasa I. and Masoudi, F. 2014. Gold Distribution in Pyrite of the Senjedeh Gold Deposit, Muteh Mining District, NW of Iran. Acta Geologica Sinica (English Edition), 88, 829-830.
-Omrani, J., Agard, P., Whitechurch, H., Benoit, M., Prouteau, G. and Jolivet, L., 2008. Arcmagmatism and subduction history beneath the Zagros Mountains, Iran, A new report of adakites and geodynamic consequences. Lithos, 106, 380–398.
-Paidar-Saravi, H., 1989. Petrographisch-lagerstattenkundliche Untersuchungen an golfuhrenden Gesteinen im Muteh Gebiet im Western vom Zentral Iran. Ruprecht-Karts Heidelberg University,174.
-Samani, B.A., 1988. Metallogeny of the Precambrian in Iran. Precambrian Resource, 39, 85– 106.
-Thiele, O., Alavi, M., Assefi, R., Hushmandzadeh, A., SeyedEmami, K., and Zahedi, M. 1968. Exploration text of the Golpaygan quadrangle map scale 1:250,000. Geological Survey of Iran. E7, 24.
-Zhao, H.X., Frimmel, H.E., Jiang,.S.Y., and Dai, B.Z., 2011. LA -ICP-MS trace element analysis of pyrite from the Xiaoqinling gold district, China: Implications for ore genesis. Ore Geology Reviews, 43, 142–153.