U–Pb zircon geochronology, petrochemical and Sr–Nd isotopic characteristic of Late Neoproterozoic granitoid of the Bornaward Complex (Bardaskan-NE Iran) R. Monazzami Bagherzadeh a,⇑ , M.H. Karimpour a , G. Lang Farmer b , C.R. Stern b , J.F. Santos c , B. Rahimi a , M.R. Heidarian Shahri a a Department of Geology, Ferdowsi University of Mashhad, Islamic Republic of Iran b Department of Geological Sciences, University of Colorado, USA c Department of Geosciences, University of Aveiro, Aveiro, Portugal article info Article history: Received 3 April 2014 Received in revised form 27 April 2015 Accepted 28 May 2015 Available online 8 June 2015 Keywords: Taknar Bornaward U–Pb dating Zircon Sr–Nd Late Neoproterozoic abstract The Bornaward Granitoid Complex (BGC) in the Taknar Zone is located in the northeast of Central Iranian Block. The BGC consists of granite, alkaligranite, syenogranite, leucogranite, granophyre, monzogranite, granodiorite, tonalite and diorite that have intruded into the center of Taknar Zone. These intrusive rocks affected by low grade metamorphism. Because of there are no reliable isotope dating data, for the Bornaward Granitoid Complex rocks have been proposed discordant ages (Jurassic, Cretaceous or even younger ages) by many studies. In the present study, new isotopic information based on zircon U–Pb dating has revealed the origin and time of the formation of the BGC. These new results do not confirm previously proposed ages. The results obtained from zircon U–Pb dating of the BGC rocks suggest late-Neoproterozoic (Precambrian) age (540–550 Ma). The Bornaward Granitoid Complex is middle-high metaluminous to lower-middle peraluminous and belongs to tholeiite, calc-alkaline to high-K calc-alkaline rock series with enrichment in LIL (Cs, Rb and Ba, U, K, Zr, Y, Th) and depletion in HIL (Sr and Nb, Ta, Ti) elements. Chondrite-normalized Rare Earth Elements (REE) plots indicate minor enrichment of LREE compared to HREE, and strong negative anomaly of Eu compared to other Rare Earth Elements. Furthermore, initial 87 Sr/ 86 Sr and 143 Nd/ 144 Nd range from 0.70351 to 0.71689 and 0.511585 to 0.512061, respectively, and initial eNd isotope values for granite, granodiorite and diorite range from 6.73 to 2.52. These all indicate that the BGC has derived from partial melting of distinct basement source regions with very high initial 87 Sr/ 86 Sr and undergoing extensive crustal contamination (S-type granite). Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction The geology of Central and Eastern Iranian terrains is immensely complicated because of the collision between the micro-continents and overprinting of many metamorphic and tec- tonic events (Stöcklin and Nabavi, 1972) as a result of continuous continental deformation in response to the ongoing convergence between the Arabian (Gondwana) and Turan (Eurasian) plates. However, the overall uniformity of Late Neoproterozoic and Paleozoic platform strata that covered the Zagros, the Central Iran and the Main Alborz provinces led to the predominant notion that all of these regions were once part of the undivided Paleozoic Arabian–Iranian platform of the Gondwanaland supercontinent (Stöcklin, 1968, 1974; Crawford, 1972). Nevertheless, neither the sparse Rb–Sr isochron data from the Central Iranian crystalline rocks (Crawford, 1977) nor the Pb–Pb isochron ages of lead ore bodies in the Central Iran (Huckriede et al., 1962) provided conclu- sive evidence for the presence of a Precambrian crust in this region. The absence of reliable isotope ages has further complicated inter- pretation of tectonic setting of other volcanic and granitic rocks. However, the study of Iranian geology has entered a new phase in the past decade. Recently, researchers (e.g., Hassanipak and Ghazi, 2000; Masoudi et al., 2002; Khalatbari-Jafari et al., 2003; http://dx.doi.org/10.1016/j.jseaes.2015.05.019 1367-9120/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +98 5138218146, mobile: +98 9155011318; fax: +98 5138212402. E-mail addresses: rmonazzami@yahoo.com (R.M. Bagherzadeh), mhkarim- pour@yahoo.com (M.H. Karimpour), Lang.Farmer@Colorado.EDU (G.L. Farmer), Charles.Stern@Colorado.EDU (C.R. Stern), Jfsantos@ua.pt (J.F. Santos), B_rahimi2000@Yahoo.com (B. Rahimi), Hshahri@Ferdowsi.um.ac.ir (M.R. Heidarian Shahri). Journal of Asian Earth Sciences 111 (2015) 54–71 Contents lists available at ScienceDirect Journal of Asian Earth Sciences journal homepage: www.elsevier.com/locate/jseaes