Saheb Granitoid Batholith, North of Kurdistan: An Evidence of Cretaceous- Paleocene Magmatism in the Sanandaj-Sirjan Zone

Document Type : Research Article

Authors

• Farid Abdollahi ¹
• Ghasem Nabatian ¹
• Jian Wei Li ²
• Maryam Honarmand ³
• Mohammad Ebrahimi ¹

¹ Department of Geology, Faculty of Sciences, University of Zanjan, Zanjan, Iran

² State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, 430074 Wuhan, China

³ Department of Earth Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran

10.22067/econg.v12i3.80773

Abstract

Introduction
The Iranian plateau is part of the Alpine-Himalayan orogenic belt, which consists of several continental fragments separated from each other by major boundary faults and/or ophiolitic suture zones (Gansser, 1981). Generally, the tectonic evolution of Iran has been controlled by the opening and closure of the Proto-Tethys, Paleo-Tethys and the Neo-Tethys during the Precambrian-Cambrian, Paleozoic and Cenozoic, respectively.
The study area is located in the northwest of Iran (the Kurdistan province) and 20 km northeast of the city of Saqez. This area is a part of the northern Sanandaj-Sirjan Zone (Aghanabati, 2005). This belt is response to opening and subduction of Neo-Tethyan oceanic crust beneath the Central Iran (Alavi, 1994). During Cretaceous-Tertiary eras, numerous granitoid bodies were formed in this belt. The Saheb granitoid is one of these granitoid bodies which mainly consists of monzogranite, quartz monzonite and quartz monzodiorite. The aim of this research study is to discuss the evolution of the Late Cretaceous-Early Paleocene Saheb granitoids in the Sanandaj-Sirjan zone based on geology, petrography and geochronology results.
 
Material and methods
In this study, 70 rock samples were collected from different types of intrusive rocks from which 30 thin sections were prepared for petrographic studies. Furthermore, four samples from the granitoid bodies (quartz monzonite, quartz monzodiorite and monzogranite) were selected for U-Pb dating. Approximately 100 to 150 zircon grains were hand-picked by a binocular microscope from each sample. Cathodo-luminescence imaging and dating of zircon grains were examined at the China University Geosciences (Wuhan branch). Geochronological analysis were performed by using the (LA)-ICP-MS method at the China University Geosciences (Wuhan branch). The detailed analytical method is presented in Liu et al. (2010a, 2010b).
 
Geology of the study area
The Saheb granitoid body is located in the Sanandaj-Sirjan zone. According to the geological map of Chapan (scale: 1/100000, Kholghi khosraghi, 1999), the Precambrian to Quaternary units are exposed in the study area. The oldest units are the Kahar, Bayandor and Soltanieh Formations with Precambrian to Cambrian age. The Permian sediments, the Ruteh and Doroud Formations, include sandstone, shale and carbonate. The Jurassic units are found in the northwest of the region, and include sandstones and shale. The Cretaceous sedimentary units are located in the south of the study area. These sediments contain sandstone, limestone, silty-limestone, shale and dolomitic limestone. During Late Cretaceous-Early Paleocene era the Saheb granitoid intruded within the oldest units and caused Fe skarn type deposits in the Saheb area. The Saheb granitoid have been cut by a series of diabasic dikes.
 
Results
The Saheb granitoid consists of several intrusive bodies containing quartz monzonite, quartz monzodiorite and monzogranite. The major minerals in the quartz monzodiorite consist of plagioclase (35- 40%), quartz (15- 20%), orthoclase (20- 25%), and mafic minerals such as biotite and amphibole (10-15%) with granular texture. The quartz monzonitic rocks show granular and poikilitic textures. Plagioclase (25- 35%), quartz, orthoclase (30- 40%), biotite and amphibole (10-15%) are the main important minerals in the quartz monzonite. Plagioclase (20-25%), quartz (20-30%), orthoclase (30-40%), biotite and amphibole (15%) are the major minerals in the monzogranite.
Zoning in zircon crystals from all four samples is well developed representing their magmatic origin (Hancar and Miller, 1993). Measurements of U-Pb in the Saheb granitoid zircon grains of quartz monzonite samples show their ages to be 62.03±0.56 Ma and 58.9±0.9 Ma. The age of monzogranite is 67.9±1.3 Ma and the age of quartz monzodiorite is 61.1±0.56 Ma. Generally, the age of this granitoid body indicates that the Saheb granitoid has occurred during the Cretaceous- Paleocene time.
 
Discussion
Based on field and microscopic studies, the Saheb granitoid bodies have been divided into three types of quartz-monzonite, quartz-monzodiorite and monzogranite. The field and mineralogical studies suggest that the Saheb granitoid is an I-type granitoid. The mineralogical variations in this granitoid suggest that the fractional crystallization has played an important role in differentiation of different compositional phases in the Saheb granitoid.
According to the geochronological results, during Late Cretaceous to Early Paleocene, the Saheb granitoid intruded within the Permian and Cretaceous units in the magmatic-metamorphic Sanandaj-Sirjan zone. These granitoids were formed by subduction of Neo-Tethys Ocean beneath the Iranian plateau. It should be mentioned that the intrusion of these granitoids into the Permian carbonates and Cretaceous carbonate and shale caused formation of skarn type iron oxide mineralization.
 
Acknowledgements
The authors are grateful to the authorities at the University of Zanjan for their financial support. We also thank the authorities at the China University Geosciences (Wuhan branch) for their financial support to perform U-Pb zircon analysis.
 
References
Aghanabati, A., 2005. Geology of Iran. Geological Survey of Iran, Tehran, 586 pp. (in Persian)
Alavi, M., 1994. Tectonics of the Zagros Orogenic belt of Iran; new data and interpretations. Tectonophysics, 299(3): 211–238.
 Gansser A., 1981. The Geodynamic History of the Himalaya. In: H.K. Gupta and F.M. Delany (Editors), Zagros Hindu Kush Himalaya Geodynamic Evolution, Vol. 3, Geodynamic Series. American Geophysical Union, Washington DC, pp. 111–121.
Kholghi khosraghi, M.H., 1999. Geological map of Chapan, scale 1: 100000. Geological Survey of Iran. (in Persian)
Liu, Y., Gao, S., Hu, Z., Gao, C., Zong, K. and Wang, D., 2010a. Continental and oceanic crust recycling-induced melt-peridotite interactions in the Trans-North China orogen: U-Pb dating, Hf isotopes and trace elements in zircons from mantle xenoliths. Journal of Petrology, 51(1–2): 537–571.
Liu, Y.S., Hu, Z.C., Zong, K.Q., Gao, C.G., Gao, S., Xu, J.A. and Chen, H.H., 2010b. Reappraisement and refinement of zircon U-Pb isotope and trace element analyses by LA-ICP-MS. Chinese Science Bulletin, 55(15):1535–1546.

Keywords

• U-Pb dating
• Paleocene
• Sanandaj-Sirjan Zone
• Saheb
• Granitoid
• Saqez
• Kurdistan

20.1001.1.20087306.1399.12.3.5.6

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References

Abdollahi, F., Nabatian, Gh., Honarmand, M. and Ebrahimi, M., 2018. Geology and petrography of Saheb granitoid intrusive bodies, north of Saqez. The 36th National and the 3rd International Geosciences Congress, Geological Survey of Iran, Tehran, Iran. (in Persian)

Agard, P.H., Omrani, J., Jolivet, L., Whitechurch, H. and Vrielynck, B., 2011. Zagros orogeny: a subduction-dominated process. Geological Magazine, 148(5–6): 692–725.

Aghanabati, A., 2005. Geology of Iran. Geological Survey of Iran, Tehran, 586 pp. (in Persian)

Ahadnejad, V., Valizadeh, M.V., Deevsalar, R. and Rezaei-Kahkhaei, M., 2011. Age and geotectonic position of the Malayer granitoids: implication for plutonism in the Sanandaj-Sirjan zone, W Iran. Neues Jahrbuch für Geologie und Palaontologie, 261(1): 61–75.

Alavi, M., 1994. Tectonics of the Zagros Orogenic belt of Iran; new data and interpretations. Tectonophysics, 299(3): 211–238.

Alavi, M., 2004. Regional stratigraphy of the Zagros fold-thrust belt of Iran and its proforeland evolution. American Journal of Science, 304(1): 1–20.

Alavi, M. and Amidi, M., 1976. Geological map of Takab, scale 1: 250000. Geological Survey of Iran. (in Persian)

Arian, M.A., Emamalipour, A. and Amini, M., 2011. Petrology and geochemistry of granitic mass and those metamorphic hallow in north-east of Saghez. Quarterly Journal of The Earth, 6(19): 65–80. (in Persian)

Arvin, M., Pan, Y., Dargahi, S., Malekizadeh, A. and Babaei, A., 2007. Petrochemistry of the Siah-Kuh granitoid stock southwest of Kerman, Iran: implications for initiation of Neotethys subduction. Journal of Asian Earth Sciences, 30(3–4): 474–489.

Azizi, H., Tanaka, T., Asahara, Y., Mehrabi, B. and Chung, S.L., 2011. Geochronological and geochemical constraints on the petrogenesis of high-K granite from the Suffiabad area, Sanandaj-Sirjan Zone, NW Iran.  Geochemistry, 71‌(4): 363–376.

 

Baharifar, A.A., Bellon, H., Pique, A. and Moein-Vaziri, H., 2004. The crystalline complexes of Hamadan (Sanandaj-Sirjan zone, western Iran): metasedimentary Mesozoic sequences affected by late Cretaceous tectono-metamorphic and plutonic events. Comptes Rendus Geoscience, 336(16):1443–1452.

Berberian, M. and King, G.C.P., 1981. Towards a paleogeography and tectonic evolution of Iran. Canadian Journal of Earth Sciences, 18(2): 210–265.

Dana, K., 2009. Investigation of geological, mineralogical and geochemical properties of Saheb skarn. M.Sc. Thesis, Tabriz University, Tabriz, Iran, 155 pp. (in Persian)

Eftekharnezhad, J., 1977. Geological map of Mahabad, scale 1: 250000. Geological Survey of Iran. (in Persian)

 Elyasi, E. and Ahangari, M., 2015. Petrology and geochemistry of felsic to mafic plutonic rocks from the Saheb, West Iran. Iranian Journal of Geology, 9(33): 15–30. (in Persian)

Gansser A., 1981. The Geodynamic History of the Himalaya. In: H.K. Gupta and F.M. Delany (Editors), Zagros Hindu Kush Himalaya Geodynamic Evolution, Vol. 3, Geodynamic Series. American Geophysical Union, Washington DC, pp. 111–121.

Ghalamghash, J., Nedelec, A., Bellon, H., Vosoughi-Abedini, M. and Bouchez, J.L., 2009. The Urumieh plutonic complex (NW Iran): record of the geodynamic evolution of the Sanandaj-Sirjan zone during cretaceous times - Part I: petrogenesis and K/Ar dating. Journal Asian Earth Sciences, 35(5): 401–415.

Ghalamghash, J., Vousoughi Abedini, M., Bellon, H., Emami, M.H., Pourmafi, M. and Rashid, H., 2003. K/Ar age dating of the Oshnavieh plutonic complex. Scientific Quarterly Geosciences Journal, 11(47–48): 16–27. (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.

Hanchar, J.M. and Miller, C.F., 1993. Zircon zonation patterns as revealed cathodoluminescence and backscattered electron images: implications for interpretation of complex crustal histories. Chemical Geology, 110(1–3): 1–13.

Hariri, A., 2004. Geological map of Saqez, scale 1: 100000. Geological Survey of Iran. (in Persian)

Hassanzadeh, J., Stockli, D.F., Horton, B.K., Axen, G.J., Stockli, L.D., Grove, M., Schmitt, A.K. and Walker, J.D., 2008. U–Pb zircon geochronology of late Neoproterozoic–Early Cambrian granitoids in Iran: implications for paleogeography, magmatism, and exhumation history of Iranian basement. Tectonophysics, 451(1–4): 71–96.

Jafari, A., Fazlnia, A. and Jamei, S., 2018. Geochemistry, petrology and geodynamic setting of the Urumieh plutonic complex, Sanandaj–Sirjan zone, NW Iran: New implication for Arabian and Central Iranian plate collision. Journal of African Earth Sciences, 139‌(1): 421–439.

Kholghi, M.H. and Vossoughi Abedini, M., 2008. Petrogenesis, geodynamics and radiometric age dating of Safakhaneh mass, Northwest of Iran. Scientific Quarterly Journal, Geosciences, 17(66): 24–39. (in Persian)

Kholghi khosraghi, M.H., 1999. Geological map of Chapan, scale 1: 100000. Geological Survey of Iran. (in Persian)

Liu, Y., Gao, S., Hu, Z., Gao, C., Zong, K. and Wang, D., 2010a. Continental and oceanic crust recycling-induced melt-peridotite interactions in the Trans-North China orogen: U-Pb dating, Hf isotopes and trace elements in zircons from mantle xenoliths. Journal of Petrology, 51(1–2): 537–571.

Liu, Y.S., Hu, Z.C., Zong, K.Q., Gao, C.G., Gao, S., Xu, J.A. and Chen, H.H., 2010b. Reappraisement and refinement of zircon U-Pb isotope and trace element analyses by LA-ICP-MS. Chinese Science Bulletin, 55(15):1535–1546.

Mahmoudi, S., Corfu, F., Masoudi, F., Mehrabi, B. and Mohajjel, M., 2011. U-Pb dating and emplacement history of granitoid plutons in the northern Sanandaj-Sirjan Zone, Iran. Journal of Asian Earth Sciences, 41(3): 238–249.

Malekzadeh Shafarodi, A. and Karimpour, M,H., 2011. Zircon U-Pb dating of Maherabad porphyry copper-gold prospect area: evidence for a late Eocene porphyry-related metallogenic epoch in east of Iran. Journal of Economic Geology, 3(1): 41–60. (in Persian with English abstract)

Masoodi, F., Mahmoodi, Sh., Mohajel, M. and Mehrabi, B., 2012. Dating of Arak –Borujerd granitoid intrusions in northern Sanandaj –Sirjan using U-Pb. Journal of Science Kharazmi University, 9(2): 437–446 pp. (in Persian)

Mazhari, S.A, Amini, S., Ghalamghash, J. and Bea, F. 2011. The origin of mafic rocks in the Naqadeh intrusive complex, Sanandaj-Sirjan Zone, NW Iran. Arabian Journal of Geosciences, 4(7–8): 1207–1214.

Mazhari, S.A, Bea, F., Amini, S., Ghalamghash, J., molina, J.F., Montero, P., Scarrow, J.H. and Williams, I.S. 2009. The Eocene bimodal Piranshahr massif of the Sanandaj-Sirjan Zone, NW Iran: a marker of the end of the collision in the Zagros orogeny. Journal of the Geological Society, 166(1): 53–69.

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.

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

Zandi, Z., jafarirad, A., Gourabjeripour, A. and Lotfi, M., 2018. Mineralization, Mineralogy and Geochemistry of Saheb Fe-Cu Deposit of Saqqez (Kurdestan), NW Iran. Open Journal of Geology, 8(5): 514–528.

Zarasvandi, A., Rezaei, M., Tashi, M., Fereydouni, Z. and Saed, M., 2019. Comparison of geochemistry and porphyry copper mineralization efficiency in granitoids of the Sanandaj-Sirjan and Urumieh-Dokhtar zones; using rare earth elements geochemistry. Journal of Economic Geology, 11(1): 1–32. (in Persian wtith English abstract)