Calk-alkaline magmatism of Jebal-e-Barez plutonic complex, SE Iran: implication for subduction-related magmatic arc
- PDF / 2,884,024 Bytes
- 22 Pages / 595.276 x 790.866 pts Page_size
- 49 Downloads / 143 Views
ORIGINAL PAPER
Calk-alkaline magmatism of Jebal-e-Barez plutonic complex, SE Iran: implication for subduction-related magmatic arc Jamal Rasouli 1 & Mansour Ghorbani 1 & Vahid Ahadnejad 2 & Giampiero Poli 3
Received: 15 March 2015 / Accepted: 10 September 2015 # Saudi Society for Geosciences 2016
Abstract The Uromia–Dokhtar Magmatic Arc (UDMA) is a northwest–southeast trending magmatic belt which is formed due to oblique subduction of Neotethys underneath Central Iran and dominantly comprises magmatic rocks. The Jebal-e-Barez Plutonic Complex (JBPC) is located southeast of the UDMA and composed of quartz diorite, granodiorite, granite, and alkali granite. Magmatic enclaves, ranging in composition from felsic to mafic, are abundant in the studied rocks. Based on the whole rock and mineral chemistry study, the granitoids are typically medium-high K calc-alkaline and metaluminous to peraluminous that show characteristics of I-type granitoids. The high field strength (HFS) and large ionic radius lithophile (LIL) element geochemistry suggests fractional crystallization as a major process in the evolution of the JBPC. The tectonomagmatic setting of the granitoids is compatible with the arc-related granitic suite, a pre-plate collision granitic suite, and a syncollision granitic suite. Field observations and petrographic and geochemical studies suggest that the rocks in this area are I-type granitoids and continental collision granitoids (CCG), continental arc granitoids (CAG), and island arc granitoid (IAG) subsections. The geothermobarometry based on the electron probe microanalysis of amphibole, feldspars, and * Jamal Rasouli [email protected] 1
Faculty of Geology, Department of Earth Sciences, Shahid Beheshti University, Tehran, Iran
2
Department of Geology, Payame Noor University, P.O Box 19395-3697, Tehran, Iran
3
Department of Earth Sciences, University of Perugia, Perugia, Italy
biotite from selected rocks of JBPC implies that the complex formed at high-level depths (i.e., 9–12 km; upper continental crust) and at temperatures ranging from 650 to 750 °C under oxidation conditions. It seems that JBPC is located within a shear zone period, and structural setting of JBPC is extensional shear fractures which are product of transpression tectonic regime. All available data suggested that these granitoids may be derived from a magmatic arc that was formed by northeastern ward subduction of the Neotethyan oceanic crust beneath the Central Iran in Paleogene and subsequent collision between the Arabian and Iranian plates in Miocene. Keywords Uromia–Dokhtar Magmatic Arc . Central Iran . Neotethys . Magmatic arc . Jebal-e-Barez
Introduction The spreading and consequent subduction of the Neotethyan oceanic crust underneath Central Iran Block (CIB) have formed the first magmatic arc, which is the so-called Sanandaj–Sirjan Magmatic Arc (SSMA). The initiation of subduction dates back to Late Triassic– Early Jurassic (Berberian and Berberian 1981, Berberian and King, 1981). Subsequent closure of the ocean cause
Data Loading...
