Geochemical and Nd-Sr Isotopic Compositions of Hypabyssal Adakites in the Torud-Ahmad Abad Magmatic Belt,Northern Central Iran Zone:Analysis of Petrogenesis and Geodynamic Implications

作     者：Fazilat Yousefi Ryan D.Mills Mahmoud Sadeghian David R.Lentz Christina Wanhainen Habibollah Ghasemi Laicheng Miao Fazilat Yousefi;Ryan D.Mills;Mahmoud Sadeghian;David R.Lentz;Christina Wanhainen;Habibollah Ghasemi;Laicheng Miao

作者机构：Department of Earth SciencesUniversity of New BrunswickFrederictonCanada Department of Geological SciencesUniversity of North Carolina at Chapel HillChapel HillUSA Faculty of Earth SciencesShahrood University of TechnologyShahroodIran Department of CivilEnvironmental and Natural Resources EngineeringLulea University of TechnologyLuleaSweden Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China 

出 版 物：《Journal of Earth Science》 (地球科学学刊（英文版）)

年 卷 期：2021年第32卷第6期

页      面：1428-1444页

核心收录：

学科分类：070902[理学-地球化学] 0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 0708[理学-地球物理学] 0704[理学-天文学] 

基　　金：supported by the NSERC Discovery to David R.Lentz 

主　　题：isotope geochemistry adakite rocks Central Iran zone Shahrood Iran 

摘      要：Eocene intermediate to felsic subvolcanic rocks of the Torud-Ahmad Abad magmatic belt(TAMB),in the northern part of the Central Iran zone,are exposed between the Torud and Ahmad Abad regions in South-Southeast *** igneous rocks include hypabyssal dacite,trachyte,andesite,trachy-andesite,and basaltic andesite;they are mainly composed of phenocrysts and microcrystalline groundmass of pyroxene,amphibole,and plagioclase,with minor biotite and titanomagnetite;they form domal structures(plugs and stocks),dikes,and sills that intruded into Neoproterozoic to cogenetic Eocene volcano-sedimentary *** on isotopic analysis of these intermediate to acidic rocks,initial ratios of^(143)Nd/^(144)Nd range from 0.512775 to 0.512893 and initial ratios of^(87)Sr/^(86)Sr range from 0.703746 to 0.705314,with quite positiveε_(Nd(i))values of+3.69 to+*** are enriched in light rare earth elements and large ion lithophile elements and depleted in heavy rare earth elements and high-field strength elements,the SiO_(2) content is(52-62)wt.%,and Na_(2)O content3 wt.%,Al_(2)O_(3) content16 wt.%,Yb1.8 ppm,and Y18 *** geological,geochemical,and Sr and Nd isotopic data are consistent with adakitic signatures originating by partial melting of the subducted Neo-Tethys oceanic slab(Sabzevar branch)and lithospheric suprasubduction zone *** mantle signatures typifying the rapidly emplaced adakitic rocks(slab(high-silica adakite)and suprasubduction zone(low-silica adakite)melts)together with their locally voluminous extent are evidences that support a locally extensional geodynamic setting;and the evidence is consistent with an evolution to local transpression in the Late Eocene in this convergent margin are environment to rifting(basalts to adakites)towards submarine conditions in the Neogene.