Adakite magmatism within the Sabzevar ophiolite zone, NE Iran: U-Pb geochronology and Sr-Nd isotopic evidences | ||
| Geopersia | ||
| مقاله 9، دوره 8، شماره 1 - شماره پیاپی 22287825، 2018، صفحه 111-131 اصل مقاله (1.21 M) | ||
| نوع مقاله: Research Paper | ||
| شناسه دیجیتال (DOI): 10.22059/geope.2017.242944.648352 | ||
| نویسندگان | ||
| Khadije Jamshidi* 1؛ Habibolah ghasemi1؛ Laicheng Miao2؛ Mahmoud Sadeghian1 | ||
| 1Department of Petrology, School of Geosciences, Shahrood University of Technology, Shahrood,Iran | ||
| 2Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, P.O. Box 9825 China | ||
| چکیده | ||
| Numerous post-ophiolite intrusions exposed into the late Cretaceous–Paleocene Sabzevar ophiolite belt, northeast Iran. The intrusions consist of calc-alkaline intermediate to felsic rocks with metaluminous to peraluminous in nature and adakitic affinities. Based on U-Th-Pb dating on separated zircons by SHRIMP Ⅱ, the emplacement age of these rocks into the ophiolite zone is constrained to ~45 Ma. All intrusions show similar MORB –like initial Nd and Sr values of 0.512911 to 0512846 and 0.704758 to 0.703790, respectively, with positive εNd (45 Ma) values of +5.26 to +6.45 implying their cogenetic nature. These isotopic signatures combined with geochemical evidences are corresponding to parental adakitic magmas derived from wet partial melting of a garnet-amphibolite source from Sabzevar subducted oceanic lithosphere. After emplacement in the deep magma storage region (equal to 700-900 MPa), this magma evolved to intensify adakitic signatures via amphibole–dominated magma fractionation. | ||
| کلیدواژهها | ||
| Geochronology؛ Sr–Nd Isotopes؛ Adakite؛ Sabzevar؛ Iran | ||
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