New hypothesis on time and thermal gradient of subducted slab with emphasis on dolomitic and shale host rocks in formation of Pb-Zn deposits of Irankuh-Ahangaran belt

زمین شناسی اقتصادی

Article 15, Volume 10, Issue 2 - Serial Number 19, March 2019, Pages 677-706   

Document Type: Research Article

DOI: 10.22067/econg.v10i2.76528

Authors

Mohammad Hassan Karimpour^{* 1}; Azadeh Malekzadeh Shafaroudi¹; Zahra Alaminia²; Abbas Esmaeili Sevieri³; Charles R. Stern⁴

¹Ferdowsi University of Mashhad

²Isfahan

³Ferdowsi University of Mashhad,

⁴Colorado

Abstract

Introduction
Mississippi Valley-Type (MVT) deposits are epigenetic zinc and lead deposits with minor copper hosted by dolostone, limestone, and locally sandstone in platform carbonate sequences inboard of major orogenic belts (Leach and Sangster, 1993; Leach et al., 2010).
The Irankuh-Ahangaran Belt, which is the most important Pb-Zn mineralized zone of Iran, is situated within the Sanandaj-Sirjan tectonic zone. This belt is 400 km in length and 100 km in width. Three deposits including Irankuh mininig district, Ahangaran and Hosseinabad deposits were studied in this article (Fig. 1).
The aim of this research is study of thermal gradient of subducted slab and age of formation of Pb-Zn deposits at Irankuh-Ahangaran belt, which is contrary information has been published so far on the type and their formation. Also, chemistry of ore-fluid in MVT deposits and impact of dolomitic and shale host rock on paragenesis, alteration, style, reserves and grade of deposits were discussed.These parameters will certainly be useful for exploration of the hidden MVT type deposits in the Irankou-Ahangan belt.
 
 Result and Discussion
The Irankuh mineralization is hosted by Cretaceous dolostone and minor Jurassic shale rocks as epigenetic. The constructive thrust fault, which has been cut the Jurassic and Cretaceous host rocks, has played a major role in the rising of fluid and formation of mineralization. Mineralization is occurred as replacement and open space filling (fault breccia, veinlets and cavity of rock) in dolostone and breccia, veinlet and open space filling in shale host rock. The mineral assembelages are Fe-rich sphalerite, Fe- and Mn-rich dolomite, ankrite, galena, minor pyrite, bituminous, calcite ± quartz ± barite within carbonate host rocks, whereas quartz, pyrite, Fe-rich sphalerite, galena, minor chalcopyrite, low Fe-dolomite, bituminous, ± barite ± calcite are important primary minerals at clastic hos rocks (Karimpour et al., 2018).
The Ahangaran deposit is very similar to Irankuh in host rock, alteration, paragenesis, and form of mineralization. Thrust fault has a constructive role for occurrence of mineralization and later destructive strike slip and normal faults have caused the displacement and destruction of mineralization.
The Hosseinabad deposit is hosted by Jurassic shale, siltstone, and sandstone rocks as vein-veinlets, breccia and open space filling with structural control. Alteratin consists of silicification, chlorite, bituminous, and minor siderite, dolomite and ankerite similar to mineralization hosted by shale in Irankuh district. The mineral assemblages are galena, Fe-rich sphalerite, pyrite, chalcopyrite and minor phyrotite. Due to the lack of a proper dolostone unit in the Husseinabad deposit, mineralization is concentrated in particular areas with low-grade and low-reserves.
Based on lithology, alteration, mineralization style, structural control by thrust faults, mineral paragenesis, and comparison with differnet types of Pb-Zn deposits, all deposits of Irankuh-Ahangaran belt are MVT-type. Deep-seated thrust faults formed during the early stages of subduction (~ 70 to 75 Ma), and played an important role in the upward migration of hydrothermal fluids from the basement to shallow depths. The geochronology of pyrite in Irankuh district based on Re-Os method indicate age of Irankuh Pb-Zn mineralization is 66.5 ± 1.6 Ma (Liu et al., 2019). Since the thrust faults have been cut the Jurassic to Upper Cretaceous rocks, and according to the absoulte age determined in Irankuh, the mineralization of this belt have been formed in the age range of 66 to 56 million years ago, mainly in the Paleocene (Fig. 15).
Karimpour and Sadeghi (2018) suggested the hydrothermal fluid originated from the dehydration of a hot and young oceanic subducted slab, which liberated Pb, Zn, and other metals, and may have removed metals from rocks and organic material of the continental crust. More than 90% of all the water within the oceanic slab was released in the depth zone of the forearc region (depth of 30 to 50 km) (Karimpour and Sadeghi, 2018). In the depth zone, Mg-rich silicate minerals (such as antigorite, hornblende, chlorite, talc) have broken and the produced fluid is rich in Mg and Fe (Fig. 17).
The ore-fluid of MVT deposits is Si-poor and Fe- and Mg- rich. Such fluid is mineralized on the hosts of the dolstone (Irankuh and Ahangaran) or Shale-Siltstone (Hossein Abad, and part of Irankuh and Ahangaran). There are significant differences in the type of paragenesis, alteration, shape, dimensions, reserves and grade in the deposits of this belt, which is controlled by the host rock type.
Based on all lithological evidence, alteration, shape of mineralization, existence of thrust faults, mineral paragenesis and specific geological and geographic location, it can be used to exploration of the hidden MVT deposits in this belt.
 
References
Karimpour, M.H., Malekzadeh Shafaroudi, A., Esmaeili Sevieri, A., Shabani, S., Allaz, J.M. and Stern, C.R., 2018b. Geology, mineralization, mineral chemistry, and ore-fluid conditions of Irankuh Pb-Zn mining district, south of Isfahan. Journal of Economic Geology, 9(2): 267–294. (in Persian with English abstract)
Karimpour, M.H. and Sadeghi, M., 2018. Dehydration of hot oceanic slab at depth 30–50 km: KEY to formation of Irankuh-Emarat Pb-Zn MVT belt, Central Iran. Journal of Geochemical Exploration, 194: 88–103.
Leach, D.L. and Sangster, D., 1993. Mississippi Valley-type lead-zinc deposits. Geological Association of Canadian. Specific Paper, 40: 289–314.
Leach, D.L, Taylor, R.D., Fey, D.L., Diehl, S.F. and Saltus, R.W., 2010. A Deposit Model for Mississippi Valley-Type Lead-Zinc Ores, Chapter A of Mineral Deposit Models for Resource Assessment. U.S. Geological Survey, Reston, Virginia, Scientific Investigations Report 2010–5070–A., 64 pp.
Liu, Y., Song, Y., Fard, M., Zhou, L., Hou, Z. and Kendricke, M.A., 2019. Pyrite Re-Os age constraints on the Irankuh Zn-Pb deposit, Iran, and regional implications. Ore Geology Reviews, 104: 148–159.

Keywords

MVT-type deposits; Shale; dolomite; Thrust fault; subduction; Malayer-Isfahan belt

References

Agard, P., Omrani, J., Jolivet, L. and Mouthereau, F., 2005. Convergence history across Zagros, Iran: Constraints from collisional and earlier deformation. International Journal of Earth Sciences, 94(3): 401–419.

Akbari, Z., 2017. Model for the genesis of Ahangaran Fe-Pb deposit (SE of Malayer), based on ore types, Geochemistry and stable isotopic studies. Ph.D. Thesis, Shahid Beheshti University, Tehran, Iran, 264 pp.

Appold, M.S. and Garven, G., 1999. The hydrology of ore formation in the Southeast Missouri District: numerical models of topography-driven fluid flow during the Ouachita Orogeny. Economic Geology, 94(6): 913–936.

Ayati, F., Dehghani, H., Mokhtari, A.R. and Mojtahedzadeh, H., 2013. Geochemistry and mineralogy studies of Gushfil Pb-Zn deposit, Irankuh, Isfahan. Journal of Analytical and Numerical Methods in Mining Engineering, 3(6): 83–91 (in Persian).

Barrie, C.T. and Hannington, M.D., 1999. Introduction: Classification of VMS deposits based on host rock composition. In C.T. Barrie and M.D. Hannington (Editors), Volcanic-Associated Massive Sulfide Deposits: Processes and Examples in Modern and Ancient Settings. Society of Economic Geologists, Reviews in Economic Geology 8, pp. 2–10.

Bradley, D.C., 1993. Role of lithospheric flexure and plate convergence in the genesis of some Appalachian zinc deposits. U.S. Geological Survey Bulletin, 2039: 35–43.

Bradley, D.C. and Leach, D.L., 2003. Tectonic controls of Mississippi Valley-type lead–zinc mineralization in orogenic forelands. Mineralium Deposita, 38(6): 652–667.

Boveiri Konari, M. and Rastad, E., 2017. Nature and origin of dolomitization associated with sulphide mineralization: new insights from the Tappehsorkh Zn-Pb (-Ag-Ba) deposit, Irankuh Mining District, Iran. Geological Journal, 53(1): 1–211

Boveiri Konari, M., Rastad, E., Mohajjel, M., Nakini, A. and Haghdoost, M., 2016. Structure, Texture, Mineralogy and Genesis of Sulphide Ore Facies in Tappehsorkh Detrital-Carbonate-Hosted Zn-Pb-(Ag) Deposit, South of Esfahan. Scientific Quarterly Journal, Geosciences, 25‌(97): 221–236. (in Persian with English abstract).

Duane, M.J. and de Wit, M.J., 1988. Pb-Zn ore deposits of the northern Caledonides; products of continental-scale fluid mixing and tectonic expulsion during continental collision. Geology, 16(11): 999–1002.

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, 37(2): 186–194.

Garven, G., 1985. The role of regional fluid flow in the genesis of the Pine Point deposit, Western Canada Sedimentary Basin. Economic Geology, 80(2): 307–324.

Ge, S. and Garven, G., 1992. Hydromechanical modeling of tectonically driven groundwater flow with application to the Arkoma Foreland Basin. Journal of Geophysical Research, 97(B6): 9119–9144.

Ghasemi, A., 1995. Facies analysis and geochemistry of Kolah-Darvazaeh, Goud-Zendan, and Khaneh-Gorgi Pb-Zn deposits from south of Irankuh. M.Sc. Thesis, Tarbiat Modares University, Tehran, Iran, 158 pp. (in Persian)

Ghasemi, A. and Talbot, C.J., 2006. A new tectonic scenario for the Sanandaj-Sirjan Zone (Iran). Journal of Asian Earth Sciences, 26(6): 683–693.

Ghazban, F., McNutt, R.H. and Schwarcz, H.P., 1994. Genesis of sediment-hosted Zn-Pb-Ba deposits in the Irankuh district, Esfahan area, west-central Iran. Economic Geology, 89(6): 1262–1278.

Hosseini-Dinani, H. and Aftabi, A., 2016. Vertical lithogeochemical halos and zoning vectors at Goushfil Zn–Pb deposit, Irankuh district, southwestern Isfahan, Iran: Implications for concealed ore exploration and genetic models. Ore Geology Reviews, 72(1): 1004–1021.

Hosseini-Dinani, H., Aftabi, A., Esmaeili, A. and Rabbani, M., 2015. Composite soil-geochemical halos delineating carbonate-hosted zinc–lead–barium mineralization in the Irankuh district, Isfahan, west-central Iran. Journal of Geochemical Exploration, 156: 114–130.

Hosseinkhani, A. and Molasalehi, F., 2013. Lead and silver mineralogical studies and lead isotope investigations in Ahangaran mine, Malayer, Iran. Scientific Quarterly Journal, Geosciences, 24(94): 359–368. (in Persian with English abstract)

Houshmandzadeh, A.R., Ohanian, T., Sahandi, M.R., Taraz, H., Aganabati, A., Soheili, M., Azarm, F. and Hamdi, B., 1975. Geological map of Eglid, scale 1:250000. Geological Survey of Iran, Tehran, Iran.

Kaiser, C.J. and Ohmoto, H., 1988. Ore-controlling structures of Mississippi Valley-type mineralization on the North American midcontinent as products of late Paleozoic convergent plate tectonism. In: G. Kisvarsanyi and S.K. Grant (Editors), North American Conference on the Tectonic Control of Ore Deposits and the Vertical and Horizontal Extent of Ore Systems, Proceedings Volume: Rolla. University of Missouri-Rolla, Missouri, pp. 424–430.

Karimpour, M.H., Malekzadeh Shafaroudi, A., Esmaeili Sevieri, A. and Shabani, S., 2018a. Mineralogy and geochemical varations of altered host rock in Irankuh Pb-Zn mining district, SW Isfahan. Journal of Advanced Applied Geology, in press. (in Persian)

Karimpour, M.H., Malekzadeh Shafaroudi, A., Esmaeili Sevieri, A., Shabani, S., Allaz, J.M. and Stern, C.R., 2018b. Geology, mineralization, mineral chemistry, and ore-fluid conditions of Irankuh Pb-Zn mining district, south of Isfahan. Journal of Economic Geology, 9(2): 267–294. (in Persian with English abstract)

Karimpour, M.H. and Sadeghi, M., 2018. Dehydration of hot oceanic slab at depth 30–50 km: KEY to formation of Irankuh-Emarat Pb-Zn MVT belt, Central Iran. Journal of Geochemical Exploration, 194: 88–103.

Kesler, S.E. and Carrigan, C.W., 2002. Discussion on “Mississippi Valley-type lead–zinc deposits through geological time: implications from recent age-dating research” by DL Leach, D.L., Bradley, D., Lewchuk, M.T., Symons, D.T.A., de Marsily, G. and Brannon, J. (2001) Mineralium Deposita, 36: 711–740. Mineralium Deposita, 37(8): 800–802.

Kesler, S.E. and van der Pluijm, B.A., 1990. Timing of Mississippi Valley-type mineralization: relation to Appalachian orogenic events. Geology, 18(11): 1115–1118.

Khosrobeygi, M., 2019. Mineralization, geochemistry and microthermometry studies in the Hossein-Abad deposit (southwest Arak). M.Sc. Thesis, University of Isfahan, Isfahan, Iran, In Press.

Leach, D.L., Bradley, D.C., Lewchuk, M., Symons, D.T.A., Brannon, J. and de Marsily, G., 2001. Mississippi Valley-type lead-zinc deposits through geological time: implications from recent age-dating research. Mineralium Deposita, 36(8): 711–740.

Leach, D.L. and Sangster, D., 1993. Mississippi Valley-type lead-zinc deposits. Geological Association of Canadian. Specific Paper, 40: 289–314.

Leach, D.L., Sangster, D.F., Kelley, K.D., Ross, R.L., Garven, G. and Allen, C.R., 2005. Sediment-hosted Pb-Zn deposits: a global perspective. Economic Geology, 100th Anniversary, 1905–2005: 561–608.

Leach, D.L, Taylor, R.D., Fey, D.L., Diehl, S.F. and Saltus, R.W., 2010. A Deposit Model for Mississippi Valley-Type Lead-Zinc Ores, Chapter A of Mineral Deposit Models for Resource Assessment. U.S. Geological Survey, Reston, Virginia, Scientific Investigations Report 2010–5070–A., 64 pp.

Liu, Y., Song, Y., Fard, M., Zhou, L., Hou, Z. and Kendricke, M.A., 2019. Pyrite Re-Os age constraints on the Irankuh Zn-Pb deposit, Iran, and regional implications. Ore Geology Reviews, 104: 148–159.

Maanijou, M., Vafaei Zad, M. and Aliani, F., 2015. Fluid inclusion and sulfur stable isotope evidence for the origin of the Ahangran Pb-Ag deposit. Journal of Economic Geology, 7(2): 343–367. (in Persian with English abstract)

Mahmoodi, P., Rastad, P., Rajabi, A. and Peter, J.M., 2018. Ore facies, mineral chemical and fluid inclusion characteristics of the Hossein-Abad and Western Haft-Savaran sediment-hosted Zn-Pb deposits, Arak Mining District, Iran. Ore Geology Reviews, 95: 342–365.

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(4): 397–412.

Momenzadeh, M., Shafighi, S., Rastad, E. and Amstutz, G.C., 1979. The Ahangaran lead-silver Deposits, SE-Malayer, west central Iran. Mineralium Deposita, 14(3): 323–341.

Rajabi, A., Rastad, E. and Canet, C., 2012. Metallogeny of Cretaceous carbonate-hosted Zn–Pb deposits of Iran: geotectonic setting and data integration for future mineral exploration. International Geology Review, 54(14): 1649–1672.

Ranjbaran, M., 1991. Sedimentary environment and diagenesis of carbonate rocks containing lead and zinc in Ahangaran mine, Malayer. M.Sc. Thesis, Tehran University, Tehran, Iran, 137 pp.

Rastad, E., 1981. Geological, mineralogical and ore facies investigations on the Lower Cretaceous stratabound Zn – Pb – Ba – Cu deposits of the Irankuh mountain range, Isfahan, west central Iran. Ph.D. Thesis, Heidelberg University, Heidelberg, Germany, 334 pp.

Reichert, J., 2007. A metallogenetic model for carbonate-hosted non-sulphide zinc deposits based on observations of Mehdi Abad and Irankuh, Central and Southwestern Iran. Ph.D. Thesis, Martin Luther University Halle Wittenberg, Halle, Germany, 152 pp.

Timoori-Asl, F., 2010. Sedimentology and petrology of Jurassic deposits and Basinal brines studies in formation of Irankuh deposit. M.Sc. Thesis, Isfahan University, Isfahan, Iran, 120 pp. (in Persian)

Timoori-Asl, F., Pakzad, H.R. and Bagheri, H., 2011. Source of metals and ore-bearing fluids in Irankuh Pb-Zn deposit. Sedimentology and Stratigraphy Research, 27(44): 83–102. (in Persian)

Zahedi, M., 1976. Geological map of Esfahan, scale 1:250,000. Geological Survey of Iran.

Zamanian, H., 1993. Mineralogy, paragenesis and genesis of lead and silver of Ahangaran, Malayer. M.Sc. Thesis, Tarbiat Moalem University, Tehran, Iran, 280 pp.