Title : ( Geochemistry and Sr–Nd isotopic characteristics of ferroan-magnesian metaluminous granites of the NW Sanandaj–Sirjan zone, Iran: granite formation in a compressional–extensional setting during Late Jurassic time )
Authors: Majid Shirmohammadi , Ali Asghar Sepahi Gerow , Jose Francisco Santos , Mohammad Maanijou , Ashraf Torkian , Hamed Vahidpour ,Access to full-text not allowed by authors
Abstract
The Almogholagh–Dehgolan region is in the North Sanandaj–Sirjan zone of NW Iran. The granites of the region are metaluminous and display geochemical and textural characteristics of transitional granites between ferroan (A-type) and I-type granites. In geotectonic discrimination diagrams, the Almogholagh–Dehgolan granites plot mainly in the fields of within-plate granites and volcanic arc granites. With the exception of the Qalaylan granites, parts of other granites resemble A2-type granites. Granites of the Qalaylan intrusive body have petrographic and geochemical features close to I-type granites and are not A-type. Primary mantle and chondrite-normalized spider diagrams show enrichments in light rare earth elements relative to heavy rare earth elements. For an age of 150 Ma, the initial 87Sr/86Sr and 143Nd/144Nd ratios vary from 0.702769 to 0.706545 and from 0.512431 to 0.512558, respectively. Epsilon Nd values vary in a relatively limited range between −0.3 and þ2.2, which corresponds to a mixed mantle– crustal source. On the basis of new geochemical and isotopic data, we suggest a geodynamic model involving partial melting of lower crustal rocks with the contribution of mantle magmas in a weakly extensional tectonic setting for the generation of the A-type granites of the region. The occurrence of ferroan (A-type) granites in this region of the Sanandaj–Sirjan zone indicates the existence of a partly extensional tectonic environment in a mainly compressional subduction-related regime in Late Jurassic time. 1. Introductio
Keywords
, A, type granites; Almogholagh–Dehgolan; ferroan; weakly extensional regime; Sanandaj– Sirjan zon@article{paperid:1102888,
author = {مجید شیر محمدی and Sepahi Gerow, Ali Asghar and خوزه فرانچسکو سانتوس and محمد مانیجو and اشرف ترکیان and حامد وحید پور},
title = {Geochemistry and Sr–Nd isotopic characteristics of ferroan-magnesian metaluminous granites of the NW Sanandaj–Sirjan zone, Iran: granite formation in a compressional–extensional setting during Late Jurassic time},
journal = {Geological Magazine},
year = {2023},
volume = {160},
number = {6},
month = {June},
issn = {0016-7568},
pages = {1065--1089},
numpages = {24},
keywords = {A-type granites; Almogholagh–Dehgolan;
ferroan; weakly extensional regime; Sanandaj–
Sirjan zon},
}
%0 Journal Article
%T Geochemistry and Sr–Nd isotopic characteristics of ferroan-magnesian metaluminous granites of the NW Sanandaj–Sirjan zone, Iran: granite formation in a compressional–extensional setting during Late Jurassic time
%A مجید شیر محمدی
%A Sepahi Gerow, Ali Asghar
%A خوزه فرانچسکو سانتوس
%A محمد مانیجو
%A اشرف ترکیان
%A حامد وحید پور
%J Geological Magazine
%@ 0016-7568
%D 2023