Geochemistry of platinum-group elements in the podiform chromitites and associated peridotites of the Nain ophiolites,Central Iran:Implications for geotectonic setting

作     者：Batoul Taghipour Somayeh Shabani Alireza K Somarin Batoul Taghipour;Somayeh Shabani;Alireza K Somarin

作者机构：Department of Earth SciencesFaculty of SciencesShiraz UniversityShirazIran Department of GeologyBrandon UniversityBrandonMBCanada 

出 版 物：《Acta Geochimica》 (地球化学学报（英文）)

年 卷 期：2021年第40卷第5期

页      面：752-772页

核心收录：

学科分类：070904[理学-构造地质学] 070902[理学-地球化学] 0709[理学-地质学] 07[理学] 

基　　金：the Research committee of Shiraz University and the Iranian Mineral Processing Research Center(IMPRC)that provided financial support for this study 

主　　题：Nain chromitite Platinum group elements Ushaped REE pattern Boninitic magma Supra-subduction zone 

摘      要：The Nain ophiolite complex with an extent of[600 km2 is a part of the Central Iranian ophiolite,which is related to the opening and subsequent closure of the Neo-Tethys *** and serpentinized harzburgite in the Nain area host podiform chromitites that occur as three(eastern Hajhossein,western Hajhossein,and Soheil Pakuh)schlieren-type tabular and aligned massive lenses with various *** most common chromitite ore textures are massive,nodular,disseminated,and banded,reflecting crystal settling *** Cr#[Cr/(Cr+Al)]ranges from 0.43 to 0.81(average 0.63).The Mg#[Mg/(Mg+Fe2+)]varies from 0.25 to 0.78(average0.62).The Nain ophiolite and hosted chromitite are generally characterized by high Cr#,reflecting crystallization from a very hot boninite magma in a MORB *** high Cr#in the Nain chromitite also indicates a high degree of melting(15%–35%)of the depleted *** average total PGE content in the ophiolitic host rock(harzburgite and dunite)and chromite are 107 and 221 ppb,*** Nain ophiolite and chromitite have high IPGE/PPGE and negative Pt*(Pt/Pt*=0.6)anomaly,which is a characteristic of high Cr#*** U-shaped REE pattern of dunite host rock suggests the interaction of depleted mantle peridotite with boninitic *** data suggest that the Nain chromitites are related to the boninitic magma emplacement in a suprasubduction zone.