Paleocene A-type igneous suites in the Sikhote-Alin(the East Asian continental margin):Petrological,geochronological,isotopic,and geodynamic constraints
作者机构:Far East Geological InstituteFar Eastern Branch of the Russian Academy of Sciences159Prospekt 100-letiya VladivostokaVladivostok 690022Russian Federation
出 版 物:《Geoscience Frontiers》 (地学前缘(英文版))
年 卷 期:2023年第14卷第6期
页 面:386-413页
核心收录:
学科分类:070904[理学-构造地质学] 070903[理学-古生物学与地层学(含:古人类学)] 0709[理学-地质学] 07[理学]
基 金:This work was financially supported by the Russian Science Foundation(No.22-27-00223)
主 题:Post-subduction magmatism Slab tear Sub-slab asthenosphere Strike-slip tectonic setting Lanthanide tetrad effect
摘 要:Global geodynamic reconstruction models of the Pacific margin of Asia refer to materials collected throughout Japan,Korea and northeastern China,but they lack data on southern ***,the Sikhote-Alin orogenic belt(NE Asia)constituted a single eastern margin of the paleo-Asian continent with the abovementioned territories in the *** isotopic,geochemical,and geochronological data show that Paleocene igneous activity(-61-55 Ma)is widely developed in south-ern *** rock compositions of the igneous rocks of this period yield ferroan,peraluminous,calc-alkaline to alkaline affinities,highly abundant LILE and HFSE(with pronounced Ba,Sr,Eu,and Ti neg-ative anomalies)and depleted *** initial melts,displaying Zr+Y+Ce+Nb350 ppm and 10,000×Ga/Al2.6,derived from an OIB-like mantle source crystallised under fairly reducing conditions(below FMQ buffer),and yield high temperature of zircon saturation(850℃),indicating typical A-type granite and related volcanic rock *** is logical to associate variations in A-type rock geochemical composition with an enrichment of the upper part of the magma chamber with fluid-mobile components involving a reditribution of major and trace elements through fluid-magmatic *** depletion in Ca,Mg,Ba,Sr,Eu in the A-type rocks is caused by an outflow of these elements by an oxi-dizing,initially reduced,acidic fluid beyond the zone of magma ***-rock Sr-Nd isotope data argue for the generation of the A-type rocks by melting of dominantly a juvenile mantle component with a subordinate component of the ancient *** variations of igneous rocks of the reference area:^(87)Sr/^(86)Sr(t)(0.7024-0.7118),ε_(Nd)(t)(-0.9 to-5.1)and T_(DM2)(934-1277 Ma),result from the mixing of the OIB-like mantle source with selective melts or from the metapelite contamination of the Samarka terrane accretionary prism and of the Zhuravlevka-Amur turbidite basin,later followed by fluid-magma