Two Types of Plagiogranite from Mesozoic Ashin Ophiolite (Central Iran): a Mark of Tectonic Setting Change from Jurassic to Cretaceous
- Авторлар: Torabi G.1, Morishita T.2, Arai S.3
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Мекемелер:
- University of Isfahan, Department of Geology
- Kanazawa University-School of Natural System, College of Science and Engineering
- Kanazawa University-Institute of Liberal Arts and Science
- Шығарылым: Том 53, № 1 (2019)
- Беттер: 110-124
- Бөлім: Article
- URL: https://journals.rcsi.science/0016-8521/article/view/156763
- DOI: https://doi.org/10.1134/S0016852119010084
- ID: 156763
Дәйексөз келтіру
Аннотация
The Ashin ophiolite is situated in the western part of Central Iran and presents two stages of Jurassic and Cretaceous spreading. The Ashin ophiolite represents fragments of the Neo-Tethys oceanic lithosphere. Plagiogranite intrusions of this ophiolite have good exposures. Plagiogranites of Cretaceous are more fresh than the metamorphosed samples of Jurassic. The main minerals of plagiogranites from the Ashin ophiolite are plagioclase, quartz and amphibole. Plagiogranites of the Jurassic have tholeitic nature with higher amounts of amphibole, \({\text{F}}{{{\text{e}}}_{2}}{\text{O}}_{3}^{*},\) TiO2, Co and lower values of Mg#, Th and Sr than the Cretaceous calc-alkaline plagiogranites. The chondrite-normalized REE patterns of these plagiogranites are characterized by higher values of REEs and negative Eu anomalies for the Jurassic samples and low values of REEs and positive Eu anomalies for the Cretaceous ones. Very low values of HREEs in the Cretaceous plagiogranites indicates a non-peridotitic source rock. We suggest that the Jurassic plagiogranites are formed by fractional crystallization of a low-K tholeitic magma; and the adakitic Cretaceous plagiogranites are formed by partial melting of an amphibolite in the subducting slab. Geochemical criteria of the Ashin plagiogranites indicate changing the Ashin ophiolite tectonic setting from a mid-ocean ridge system in the Jurassic to a supra-subduction zone in the Cretaceous.
Негізгі сөздер
Авторлар туралы
G. Torabi
University of Isfahan, Department of Geology
Хат алмасуға жауапты Автор.
Email: Torabighodrat@sci.ui.ac.ir
Иран, Isfahan, P.C. 8174673441
T. Morishita
Kanazawa University-School of Natural System, College of Science and Engineering
Email: Torabighodrat@sci.ui.ac.ir
Жапония, Kanazawa, P.C. 920‒1192
S. Arai
Kanazawa University-Institute of Liberal Arts and Science
Email: Torabighodrat@sci.ui.ac.ir
Жапония, Kanazawa, 920‒1192
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