The spatial and compositional evolution of the Jurassic Ghorveh-Dehgolan plutons of the Zagros Orogen, Iran: SHRIMP zircon U-Pb and Sr and Nd isotope evidence

Authors

  • S. YAJAM Department of Geology, Faculty of Earth Sciences, Kharazmi University. 49 Mofatteh Av., Tehran 15614, Iran. Payam Nppr University of Manjil. Isargaran Av., Manjil, Iran.
  • P. MONTERO Departamento de Mineralogía y Petrología, Facultad de Ciencias, Universidad de Granada. Av/ Fuentenueva, s/n, 18002, Granada, Spain.
  • J.H. SCARROW Departamento de Mineralogía y Petrología, Facultad de Ciencias, Universidad de Granada. Av/ Fuentenueva, s/n, 18002, Granada, Spain.
  • J. GHALAMGHASH Geological Survey of Iran, Research Institute for Earth Sciences. PO Box 13185-1494, Tehran, Iran.
  • S. M. H. RAZAVI Department of Geology, Faculty of Earth Sciences, Kharazmi University, 49 Mofatteh Av., Tehran 15614, Iran.
  • F. BEA Departamento de Mineralogía y Petrología, Facultad de Ciencias, Universidad de GranadaAv/ Fuentenueva, s/n, 18002, Granada, Spain.

Keywords:

U-Pb SHRIMP dating, Sanandaj-Sirjan Zone, Neoproterozoic Arabian-Nubian crust, Neotethys, A-type granites

Abstract

The Ghorveh-Dehgolan plutons of the northern Sanandaj-Sirjan Zone, Zagros Orogen, comprise seven composite intrusive bodies that were generated during northeastward subduction of Neotethys beneath the Iranian sector of the Eurasian plate. Zircon U-Pb SHRIMP dating reveals that the magmatic activity spanned from ~160 to ~140Ma. It started with intrusion of arc-related calc-alkaline mafic to intermediate rocks closely followed by felsic I-type granitoids. This magmatism was post-dated by felsic alkaline A-type granites. In addition to compositional changes over time, the plutons forming the arc young towards the southwest: the north Ghorveh batholith (161±4Ma) and Shanevareh (160±2Ma); Qalaylan (159±3Ma); then central Ghorveh, Galali and Saranjianeh (151±0.2Ma to 148±1Ma); and, lastly, the south Ghorveh batholith (147±3Ma) and Bolbanabad-Havarpan (144±1Ma). Whatever the process driving the changes, be it arc- or ridge-collision with the subducting system, slab roll-back, slab breakoff, subduction initiation transference, etc., the progression from I-type to A-type magmatism appears to mark a significant change from a collisional to an extensional setting in the region in the Late Jurassic. Geochemical and isotopic characteristics of the Ghorveh-Dehgolan plutons indicate that Arabian-Nubian-like crust was an important component of the magmatic sources.

Author Biographies

S. YAJAM, Department of Geology, Faculty of Earth Sciences, Kharazmi University. 49 Mofatteh Av., Tehran 15614, Iran. Payam Nppr University of Manjil. Isargaran Av., Manjil, Iran.

PhD student of Faculty of geoscience, Kharazmi university, Tehran, Iran.

P. MONTERO, Departamento de Mineralogía y Petrología, Facultad de Ciencias, Universidad de Granada. Av/ Fuentenueva, s/n, 18002, Granada, Spain.

Prof. Dr. Pilar G. Montero. Dpt. Mineralogía y Petrología. Fac. Ciencias. Campus Fuentenueva.

Univ. Granada. 18002 Granada (Spain)

J.H. SCARROW, Departamento de Mineralogía y Petrología, Facultad de Ciencias, Universidad de Granada. Av/ Fuentenueva, s/n, 18002, Granada, Spain.

Dr. Jane H.Scarrow. Dpt. Mineralogía y Petrología. Fac. Ciencias. Campus Fuentenueva.

Univ. Granada. 18002 Granada (Spain)

J. GHALAMGHASH, Geological Survey of Iran, Research Institute for Earth Sciences. PO Box 13185-1494, Tehran, Iran.

Dr. Jalil Ghalamghash, Manager for regional geology at Geological survey of Iran

S. M. H. RAZAVI, Department of Geology, Faculty of Earth Sciences, Kharazmi University, 49 Mofatteh Av., Tehran 15614, Iran.

Dr. S.M.H.Razavi, department of geology, Faculty of geoscience, Kharazmi university,Tehran,Iran

F. BEA, Departamento de Mineralogía y Petrología, Facultad de Ciencias, Universidad de GranadaAv/ Fuentenueva, s/n, 18002, Granada, Spain.

Prof. Dr. Fernando Bea

Dept. Mineralogía y Petrología

Campus Fuentenueva, Univ. Granada

18002 Granada, Spain

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Published

2015-03-26

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