New geological, geochronological and geochemical investigations on the Khoy ophiolites and related formations, NW Iran

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• 作者：Morteza Khalatbari-Jafari ; Thierry Juteau ; Hervé ; Bellon ; Hubert Whitechurch ; Jo Cotten ; Hashem Emami
• 关键词：Ophiolites ; Iran ; Tethys ; ⁴⁰K– ; ⁴⁰Ar ages ; Metamorphism ; Trace element patterns
• 刊名：Journal of Asian Earth Sciences
• 出版年：2004
• 出版时间：August 2004
• 年：2004
• 卷：23
• 期：4
• 页码：507-535
• 全文大小：3327 K

文摘

This paper gives a detailed geological description of the region of Khoy (NW Iran) and its ophiolites, and presents a new geological map. The main conclusion is that there are not one, but two ophiolitic complexes in the Khoy area: (1) an old, poly-metamorphic ophiolite, tectonically included within a metamorphic subduction complex, whose oldest metamorphic amphiboles yield a Lower Jurassic apparent ⁴⁰Kn–⁴⁰Ar age, and whose primary magmatic age should logically be pre-Jurassic; (2) a younger non metamorphic ophiolite of Upper Cretaceous age, overlain by a turbiditic, flysch-like volcanogenic series, of Upper Cretaceous-Lower Paleocene age. This latter ophiolite was created at a slow-spreading oceanic center, according to the lherzolitic mantle sequence, the small volume of gabbroic rocks, the absence of a diabasic sheeted-dike complex, and the abundant phyric basalts in the extrusive sequence. A scenario for the geodynamic evolution of the Khoy oceanic basin is proposed in conclusion.