Mineralogy, alteration, fluid inclusion and geochemical constraints of the Tappeh-Khargoosh Cu-Au deposit (SW Ardestan)

زمین شناسی اقتصادی

Article 1, Volume 10, Issue 2 - Serial Number 19, March 2019, Pages 299-324   

Document Type: Research Article

DOI: 10.22067/econg.v10i2.62445

Authors

Elham Hashemian¹; Hemayat Jamali^{* 1}; Jamshid Ahmadian²

¹Isfahan

²Payame Noor

Abstract

Introduction
The Tappeh-Khargoosh area is located at the 15 km SW of Ardestan, in the middle section of the Urumieh-Dokhtar magmatic arc (Aghanabati, 2004). Exploration in the study area began in 2006 by Kani Pajohan-e- Spadana Company and continued in detail by the Ardestan Copper-Gold Company. Their exploration activities consist of preparing the geological map (1:5000 in scale), drilling trenches and boreholes. Also minor extraction has been done. In this paper, our focus is on mineralogy, alteration, geochemistry and fluid inclusion of the Tappeh-Khargoosh deposit for determining the genesis of mineralization. The results of this study can be used for more exploration in the study and adjacent areas.
 
Methodology
Samples collected along a traverses perpendicular to the mineralized veins and their alteration haloes. The geometry, morphology, mineralogy and texture of mineralization were examined. After careful microscopic studies, 7 samples were analyzed by the XRF method in the laboratory of the Tarbiat Modarres University and Iranian Mineral Processing Research Center (IMPRC) in Karaj. Six thin-polished sections and 8 polished sections were examined. Also, 32 samples of mineralized and altered zones were analyzed by Inductively Coupled Plasma with optical emission spectrometer (ICP-OES) in IMPRC. Six samples were analyzed for gold by Atomic Absorption Spectroscopy (A.A.S) method in the Kimia Pajoh Alborz laboratory. Three double polished sections prepared from mineralized quartz vein and micro thermometric studies had been analyzed by a model HF-S90 microscope in the University of Isfahan. For detail understanding of mineral composition and determination of some fine and rare minerals, the electron microprobe analyzing (EMPA) technique (model SX100) is used in IMPRC.
 
Discussion and results
The Tappeh-Khargoosh deposit consist of quartz vein and veinlets which occur as open space filling in Eocene andesite and dacite. The mineralized veins mainly occur in the fault zones. The subparallel fault systems of dextral strike sleep Qom-Zefreh crustal scale fault (Tajmir Riahi et al., 2012) has had the main role in localization of mineralizing fluids.
The alteration mainly consist of silicificaion, propylitization with minor sericitization and argillization represented as vein-veinlets, dissemination and pervasively in host volcanics. These alteration assemblages are indicative of near neutral to little alkaline hydrothermal fluids (Simmons et al., 2005). The silicic alteration has occurred in a wide range of pH and temperature, while the argillic alteration has occurred in low temperature and a wide range of pH. So where the silicic and argillic alterations have occurred together, the temperature of the causing fluid must be lower in the range of clay mineral stability field (Robb, 2005). The fluid inclusion in the quartz shows the low temperature (137-194˚C) and low to medium salinity (4-12.5 %) which coincide with low to medium sulfidation epithermal deposit conditions. According to fluid inclusion data, bisulfides were the main ligand for metals transportation. The absence of halite/sylvite daughter minerals in fluid inclusions and low salinity of fluid inclusions show that the chloride complexes not act as effective ligands. Opposed to high sulfidation epithermal deposits in which the magmatic waters are common, in the low sulfidation type, the meteoric waters are dominant (Foster, 1991; Vahabi Moghadam, 1993). Dilution by cold and low salinity meteoric water has the main role in mineral deposition. Pyrite, chalcopyrite, bornite, chalcocite and native gold are the primary minerals and hematite, goethite, covellite, chalcocite, cuprite, malachite, chrysocolla, azurite and atacamite are the secondary minerals, which have occurred as veinlets, open space filling, colloform, amygdal filling and dissemination in quartz vein and host rocks. Fine grain gold had be seen in the colloidal secondary Fe-oxides, which indicate that the gold probably occurred primarily in sulfide minerals and was released in the supergene process. According to microprobe analysis, Ag was measured as impurity in chalcocite. These features coincide with high correlation coefficient between precious metals and copper. So, the Cu can be used as a pathfinder element for gold exploration in this and adjacent areas. The abundance of Cu-bearing secondary minerals in the surface, indicate that the Cu has not leached effectively as a result of the little amount of pyrite and aridity of the area. In this condition, Cu which was created by oxidation of primary Cu minerals was fixed in the surface as silicate, carbonate and oxide minerals (Chavez, 2000). Geology, geometry, texture and structure, geochemistry, alteration schema, fluid inclusion and mineralogical data of the Tappeh-Khargoosh make it similar to low sulfidation (L.S) epithermal deposits.
 
References
Aghanabati, A., 2004. Geology of Iran. Geological Survey of Iran Publications, Tehran, 709 pp. (in Persian)
Chavez, W.X., 2000. Supergene oxidation of copper deposits: Zoning and distribution of copper oxide minerals. Society of Economic Geologists Newsletter, 41(1): 10–21.
Foster, R.P., 1991. Gold metallogeny and exploration. Springer, London, 431 pp.
Robb, L., 2005. Introduction to ore- forming processes. Blackwell Publication, Australia. 373 pp.
Simmons, S.F., White, N.C. and John, D.A., 2005. Geological characteristics of epithermal precious and base metal deposits. In: J.W. Hedenquist, J.F.H. Thompson, R.J. Goldfarb and J.P. Richard (Editors), Economic Geology, 100th Anniversary Volume: 1905-2005. Society of Economic Geologists, Littleton, Colorado, pp. 485–522.
Tajmir Riahi, Z., Beigi, S., Safaei, H. and Nadimi, A., 2012. Identification active faults and seismic tectonic Shahreza area. 31th Geosciences Conference, Geological survey and mineral explorations, Tehran, Iran. (in Persian)
Vahabi Moghadam, B., 1993. Petrographic and petrology metamorphic- magmatic rocks south of Nain. M.Sc. Thesis, University of Tarbiat Moalem, Tehran, Iran, 250 pp.

Keywords

Mineralography; Alteration; fluid inclusion; Geochemistry; low Sulfidation Epithermal; Tappeh-Khargoosh; Ardestan

References

Aghanabati, A., 2004. Geology of Iran. Geological Survey of Iran Publications, Tehran, 709 pp. (in Persian)

Alikhani, M., Shamanian, Gh.H. and Jafary Zanglanelo, M., 2014. Mineralization and hydrothermal alteration of the vein system of Tajrud, south of Neyshabur. Journal of Economic Geology, 5(2): 325–339. (in Persian)

Barnes, H.L., 1997. Geochemistry of hydrothermal ore deposits. John Wiley and Sons, New York, 992 pp.

Bodnar, R.J., 1993. Revised equation and table for determining the freezing point depression of H2O-NaCl solutions. Geochimica et Cosmochimica Acta, 57(3): 683–684.

Chavez, W.X., 2000. Supergene oxidation of copper deposits: Zoning and distribution of copper oxide minerals. Society of Economic Geologists Newsletter, 41(1): 10–21.

Cisternas, M.E. and Hermosilla, J., 2006. The role of bitumen in strata-bound copper deposit formation in the Copiapo area, Northern Chile. Mineralium Deposita, 41(4): 339–355.

Cooke, D.R., Mcpall, D.C. and Blom, M.S., 1996. Epithermal gold mineralization, Acupan, Baguio District, Philipines, geology, mineralization, alteration and the thermochemical environment of ore deposition. Economic Geology, 91(2): 243–272.

Craig, J.R. and Vaughan, D.J., 1981. Ore microscopy and ore petrography. Wiley Interscience, New York, 417 pp.

Dong, G., Morrison, G. and Jaireth, H., 1995. Quartz texture in epithermal veins, Queensland- classification, Origin, and implication. Economic geology, 90(6): 1841–1856.

Feyzi, M., Ebrahimi, M., Hossein Kouhestani, H. and Mokhtari, M.A.A., 2017. Geology, mineralization and geochemistry of the Aqkand Cu occurrence (north of Zanjan, Tarom-Hashtjin zone). Journal of Economic Geology, 8(2): 507–524. (in Persian with English abstract)

Foster, R.P., 1991. Gold metallogeny and exploration. Springer, London, 431 pp.

Guilbert, J.M. and Park, Ch.F., 1986. The geology of ore deposits. Freeman and company, New York, 985 pp.

Hashemian, E., 2016. The study of alteration, geochemistry, fluid inclusion and genesis of the Tappeh- Khargoosh Cu-Au deposit, southwest Ardestan. M.Sc. thesis, University of Isfahan, Isfahan, Iran, 115 pp.

Hayba, D.O., Bethke, P.M., Heald, P. and Foley, N.K., 1985. Geologic, mineralogic, and geochemical characteristics of volcanic-hosted epithermal precious-metal deposits. In: B.R. Berger and P.M. Bethke (Editors), Geology and Geochemistry of Epithermal Systems. Society of Economic Geologists, Chelsea, pp. 129–166.

Hedenquist, J.W., 1987. Mineralization associated with volcanic-related hydrothermal systems in the circum-Pacific basin. In: M.K., Horn (Editor), Transction of the Fourth Circum-Pacific Energy and Mineral Resources Conference. American Association of Petroleum Geologists, Singapore, pp. 513–524.

Hedenquist, J.W. and Arribas, A., 2017. Epithermal ore deposits: First-order features relevant to exploration and assessment. 14th Conference: Mineral Resources to Discovery. The Society for Geology Applied to Mineral Deposits Biennial Meeting, Quebec, Canada.

Hedenquist, J.W., Arribas, A. and Gonzalez-Urien, E., 2000. Exploration for epithermal gold deposits. Reviews in Economic Geology, 13(7): 221–244.

Huston, D.L. and Large, R.R., 1989. A chemical model for the concentration of gold in volcanogenic massive sulphide deposits. Ore Geology Reviews, 4(3): 171–200.

John, D.A., 2011. Epithermal gold-silver deposits of the Hauraki Goldfield, New Zealand: An Introduction. Economic Geology, 106(6): 915–919.

Kojima, S., Astudillo, J., Trista, D. and Hayashi, K., 2003. Ore mineralogy, fluid inclusion, and stable isotopic characteristics of stratiform copper deposits in the coastal Cordillera of Northern Chile. Mineralium Deposita, 38(1): 208–216.

Kojima, S., Trista-Aguilera, D. and Hayashi, K., 2008. Genetic aspects of the manto-type copper deposits. Resource Geology, 59(1): 87–98.

Lowell, J.D. and Guilbert, J.M., 1970. Lateral and vertical alteration-mineralization zoning in porphyry ore deposits. Economic Geology, 65(4): 373–408.

Maksaev, V. and Zentilli, M., 2002. Chilean Strata-bound Cu-(Ag) Deposits. An Overview: T.M. Porter (Editor), Hydrothermal Iron Oxide Copper-Gold and Related Deposits: A Global Perspective. Porter GeoConsultancy Publishing, Adelaide, pp. 185–205.

Mauk, J.L. and Simpson, M., 2007. Geochemistry and stable isotope composition of altered rocks at the Golden Cross epithermal Au-Ag deposit, New Zealand. Economic Geology, 102(5): 841–871.

Mehvari, R., Shamsipour, R., Bagheri, H., Noghreyan, M. and Mackizadeh M.A., 2010. Mineralogical and fluid inclusion studies in the Kalchueh copper- gold deposit, East of Isfahan. Journal of Economic Geology, 1(1): 47–55. (in Persian with English abstract)

Moncada, D., Mutchler, S., Niebto, A., Reynolds, T.J., Rimstidt, J.D. and Bodnar, R.J. 2012. Mineral textures and fluid inclusion petrography of the epithermal Ag-Au deposits at Guanajuato, Mexico: Application to exploration. Geochemical Exploration, 114(12): 20–35.

Monecke, T., Kempe, U. and Gotze, J., 2002. Genetic significance of the trace element content in metamorphic and hydrothermal quartz: a reconnaissance study. Earth and Planetary Science Letters, 202(3–4): 709–724.

Nadimi, A., 2010. Active Strike- slip faults in the central part of the Sanandaj-Sirjan Zone of Zagros Orogen (Iran). Ph.D. Thesis, University of Warsaw, Warsaw, Poland, 121 pp.

Oliveros, V., Feraud, G., Aguirre, L., Ramirez, L., Fornari, M., Palacios, C. and Parada, M., 2008. Detailed 40Ar/39Ar dating of geologic events associated with the Mantos Blancos copper deposit, northern Chile. Mineralium Deposita, 43(3): 281–293.

Omrani, J., Agard, P., Whitechurch, H., Benoit, M., Prouteau, G. and Jolivet, L., 2008. Arc-magmatism and subduction history beneath the Zagros Mountains, Iran: A new report of adakites and geodynamic consequences. Lithos, 106(3): 380–398.

Pirajno, F., 2009. Hydrothermal processes and mineral systems. Springer, New York, 1273 pp.

Pourkaseb, H., Zarasvandi1, A., Saed, M. and Ali Reza Davoudian Dehkordy, A.R., 2017. Magmatic-hydrothermal fluid evolution of the Dalli porphyry Cu-Au deposit; using Amphibole and Plagioclas mineral chemistry. Journal of Economic Geology, 9(1): 73–92. (in Persian with English abstract)

Radfar, J., 1992. Geological map quadrangle Ardestan, scale 1:100000. Geological Survey of Iran. (in Persian)

Ramdohr, P., 1980. The Ore mineral and their intergrowths. Pergamon, New York, 1205 pp.

Ramirez, L.E., Palacios, C., Townley, B., Parada, M.A., Sial, A.N., Fernandez-Turiel, J.L., Gimeno, D., GarciaValles, M. and Lehmann, B., 2006. The mantos blancos copper deposit: An upper Jurassic breccia-style hydrothermal system in the coastal range of northern Chile. Mineralium Deposita, 41(3): 246–258.

Robb, L., 2005. Introduction to ore- forming processes. Blackwell Publication, Australia. 373 pp.

Rowland, J.V. and Simmons, S.F., 2012. Hydrologic, magmatic, and tectonic controls on hydrothermal flow, Taupo Volcanic Zone, New Zealand: Implications for the formation of epithermal vein deposits. Economic Geology, 107(3): 427–457.

Salehi, M., 2015. Petrology and geochemistry of volcanic rocks, southwest of Ardestan. M.Sc. Thesis, Tarbiat Modarres University, Tehran, Iran, 100 pp.

Sergio Espinoza, R., Hector Veliz, G., Justo Esqivel, L., Jaime Arias, F. and Aldo Mroago, B., 1994. The Cupriferous Province of the costal Range, Northern Chile. Society of Economic Geologists, London, 16 pp.

Shahabpour, J., 2007. Economic Geology. Shahid Bahonar University, Kerman, 536 pp. (in Persian)

Shepherd, T.J., Rankin, A.H. and Alderton, D.H.M., 1985. A practical guide to fluid inclusion studies. Glasgow: Blackie, Chapman and Hall, New York, 239 pp.

Sikka, D.B., Petruk, W., Nehru, C.E. and Zhang, Z., 1991. Geochemistry of secondary copper minerals from Proterozoic porphyry copper deposit, Malanjkhand, India. Ore Geology Reviews, 6(2–3): 257–290.

Sillitoe, R.H. and Hedenquist, J.W., 2003. Linkages between volcanotectonic settings, ore-fluid compositions, and epithermal precious metal deposits. Society of Economic Geologists, Special Publication, 10(1): 315–343.

Simmons, S.F. and Browne, P.R.L., 2000. Hydrothermal minerals and precious metals in the Broadlands-Ohaaki Geothermal System: Implications for understanding low-sulfdation epithermal environments. Economic Geology, 95(5): 971–999.

Simmons, S.F., White, N.C. and John, D.A., 2005. Geological characteristics of epithermal precious and base metal deposits. In: J.W. Hedenquist, J.F.H. Thompson, R.J. Goldfarb and J.P. Richard (Editors), Economic Geology, 100th Anniversary Volume: 1905-2005. Society of Economic Geologists, Littleton, Colorado, pp. 485–522.

Simpson, M., Mauk, J.L. and Simmons, S.F., 2001. Hydrothermal alteration and hydrologic evolution of the Golden Cross epithermal Au-Ag deposit, New- Zealand. Economic Geology, 96(4): 773–796.

Sparkes, G.W., 2012. A prospector’s guide to alteration and epithermal gold mineralization – Examples from Eastern Avalon. Technical Report, Geological Survey Newfoundland and Labrador, Canada, 27 pp.

Tajmir Riahi, Z., Beigi, S., Safaei, H. and Nadimi, A., 2012. Identification active faults and seismic tectonic Shahreza area. 31th Geosciences Conference, Geological survey and mineral explorations, Tehran, Iran. (in Persian)

Trista-Aguilera, D., Barra, F., Ruiz, J., Morata, D., Talavera-Mendoza, O., Kojima, S. and Ferraris, F., 2006. Re-Os isotope systematics for the Lince–Estefania deposit: constraints on the timing and source of copper mineralization in a stratabound copper deposit, Coastal Cordillera of Northern Chile. Mineralium Deposita, 41(1): 99–105.

Vahabi Moghadam, B., 1993. Petrographic and petrology metamorphic- magmatic rocks south of Nain. M.Sc. Thesis, University of Tarbiat Moalem, Tehran, Iran, 250 pp.

White, N.C. and Hedenquist, J.W., 1995. Epithermal gold deposits: Styles, characteristics, and exploration. Society of Economic Geologists Newsletter, 23(1): 9–13.

Whitney, D.L. and Evans, B.W., 2010. Abbreviations for names of rock-forming minerals. American Mineralogist, 95(1): 185–187.

Wilkinson, J.J., 2001. Fluid inclusions in hydrothermal ore deposits. Lithos, 55(1–4): 229–272.

Yeganefar, H., 2007. Petrology and Geochemistry of volcanic rocks south Ardestan. M.Sc. Thesis, Tarbiat Modarres University, Tehran, Iran, 118 pp. (in Persian with English abstract)

Yeganefar, H., Ghorbani, M.R., Shinjo, R. and Ghaderi, M., 2013. Magmatic and geodynamic evolution of Urumieh–Dokhtar basic volcanism, Central Iran: major, trace element, isotopic, and geochronologic implications. International Geology Review, 55(6): 767–786.

Yılmaz, H., Oyman, T., Arehart, G.B., Çolakoğlu, A.R. and Billor, Z., 2007. Low-sulfidation type Au-Ag mineralization at Bergama, Izmir, Turkey. Ore Geology Reviews, 32(1–2): 81–124.

Yılmaz, H., Oyman, T., Sönmez, F.N., Arehart, G.B. and Billor, Z., 2010. Intermediate sulfidation epithermal gold-base metal deposits in tertiary subaerial volcanic rocks, Şahinli/Tespih Dere (Lapseki/Western Turkey). Ore Geology Reviews, 37(3–4): 236–258.