Document Type : Original Research Paper

Authors

1 Ph.D., Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran

2 Ph.D., Faculty of Basic Science, Tarbiat Modarres University, Tehran, Iran

3 Professor, Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran

Abstract

The Fe-Pb Ahangaran deposit, hosted by tuffaceous siltstone of the Early Cretaceous sedimentary sequence in the northern part of the Malayer-Esfahan Metallogenic Belt (MEMB), Iran. Ore mineralization occurred as stratiform and a widespread veinlet zone in the upper part of Lower Cretaceous terrigenous unit (Kc). Four different ore types can be distinguished in deposit include: (1) veinlet (feeder) zone, (2) sulfide-Fe- oxide stratiform ore (3) barite ore and (4) vein ore. Ore minerals in the different ore types are pyrite, siderite, magnetite, galena, barite, chalcopyrite and tetrahedrite and rare minerals are pyrrhotite, arsenopyrite, and freibergiteCarbonatization and silicification are the main hydrothermal alterations in this deposit. The orebodies in the Ahangaran deposit have been replaced by iron oxide minerals in supergene process and have been formed a thick gossan zone. The textural and mineralogical data provide evidence of three stages of mineralization (Early, main and late stage) in Ahangaran deposit. According to evidences such as tectonic setting, type of host rock, geometry of deposit, sulfide-Fe oxide ore types, textures and structures indicate that the Ahangaran deposit is compatible with a sub-seafloor replacement mineralization that has been suggested for some Sedex deposits.

Keywords

Main Subjects

References
Broadbent, G. C., Andrews, S. J. and Kelso, I. J., 2002- A decade of new ideas: geology and exploration history of the Century Zn–Pb–Ag deposit, Northwestern Queensland, Australia. In: Goldfarb, R.J., Nielsen, R.L. (eds.), Integrated Methods for Discovery: Global Exploration in the Twenty-First Century, vol. 9. Society of Economic Geologists Special Publication SPE.3, p. 119- 140.
Ehya, F., Lotfi, M. and Rasa, I., 2010- Emarat carbonate-hosted Zn–Pb deposit, Markazi Province, Iran: A geological, mineralogical and isotopic (S, Pb) study.  Journal of Asian Earth Sciences, v. 37, p. 186-194.
Ghasemi, A. and Talbot, C. J., 2006- A new tectonic scenario forthe Sanandaj–Sirjan Zone (Iran): Journal of Asian EarthSciences, v. 26, p. 683–693.
Ghazban, F., McNutt, R. H., and Schwarcz, H. P., 1994- Genesis of sediment-hosted Zn-Pb-Ba deposits in the Iran Kouh district, Esfaha area, west-Central Iran. Economic Geology, v. 89, p. 1262- 1278.
Goodfellow, W. D. and Lydon, J. W., 2007- Sedimentary exhalative (SEDEX) deposits, in Goodfellow, W.D., (eds.), Mineral deposits of Canada: A synthesis of major deposit types, district metallogeny, the evolution of geological provinces, and exploration methods. Geological Association of Canada, Mineral Deposits Division, Special Publication 5, p. 163-183.
Kelley, K. D., Leach, D. L., Johnson, C. A., Clark, J. L., Fayek, M., Slack, J. F., Anderson, V. M, Ayuso, R. A. and Ridley, W. I, 2004- Textural, compositional, and sulfur isotope variations of sulfide minerals in the Red Dog Zn-Pb-Ag deposits, Brooks Range, Alaska. Implications for ore formation. Economic Geology, v. 99, p. 1509- 1532.
Large, R. R., McGoldrick, P., Bull, S. and Cooke, D., 2004- Proterozoic startiform  sediment-hosted zinc-lead-silver deposits of northern Australia, in Deb, M. Goodfellow, W.D., (eds.), Sediment-hosted lead-zinc sulphide deposits: Attributes and models of some major deposits of India, Australia and Canada. Narosa publishing house, Delhi, India, p.1- 24.
Leach, D. L., Bradley, D. C., Huston, D., Pisarevsky, S. A., Taylor, R. D. and Gardoll, S. J., 2010- Sediment-hosted lead-zinc deposits in Earth history: Economic Geology, v. 105, p. 593- 625.
Mohajjel, M. and Fergusson, C. L., 2014- Jurassic to Cenozoic tectonics of the Zagros Orogen in northwestern Iran. International Geology Review,v. 56, p. 263- 287.
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, v. 21, p. 397- 412.
Momenzadeh, M., 1976- Stratabound lead–zinc ores in the lower Cretaceous and Jurassic sediments in the Malayer–Esfahan district, lithology, metal content, zonation and genesis. Unpublished Ph.D. thesis, University of Heidelberg, 300 p.
Rajabi, A., Rastad, E. and Canet, C., 2012a- Metallogeny of Cretaceous carbonatehosted Zn- Pb deposits of Iran: geotectonic setting and data integration for future mineral exploration, International Geology Review, v. 54(14), p. 1649- 1672.
Rajabi, A., Rastad, E., Alfonso, P. and Canet, C., 2012b- Geology, ore facies and sulphur isotopes of the Koushk vent-proximal sedimentary-exhalative deposit, Posht-e-Badam Block, Central Iran. International Geology Review, v. 5(14), p.1635- 1648.
Rastad, E., 1981- Geological, mineralogical, and facies investigations on the Lower Cretaceous stratabound Zn–Pb–(Ba–Cu) deposits of the Iran Kouh Mountain Range, Esfahan.Unpublished Ph.D. thesis, Heidelberg, University of Heidelberg, 334 p.
Reynold, N. and Muhling, P., 2011- Diversity of Zinc-Lead Metallogeny Implications for Targeting and Discovery. AIG Base Metals Seminar, Perth, Australia.
Velasco, F., Herrero, J. M., Suárez, S., Yusta, I., Alvaro, A. and Tornos, F., 2013- Supergene features and evolution of gossans capping massive sulphide deposits in the Iberian Pyrite Belt. Ore Geology Reviews, v. 53, p. 181- 203.
Wilkinson, J. J., 2014- Sediment-Hosted Zinc–Lead Mineralization: Processes and Perspectives. Treatise on Geochemistry 2nd Edition, p. 219-249.