The tectonic setting of Jurassic magmatism in the Northeast China(NE China)is unclear.Here,we present new petrological,whole-rock geochemical,zircon U-Pb geochronological,and zircon Lu-Hf isotope data for Jurassic gra...The tectonic setting of Jurassic magmatism in the Northeast China(NE China)is unclear.Here,we present new petrological,whole-rock geochemical,zircon U-Pb geochronological,and zircon Lu-Hf isotope data for Jurassic granitoids of the Wulong region,Liaodong Peninsula,NE China.Laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS)zircon U-Pb data indicate that these granitoids were emplaced at 165-156 Ma.The biotite monzogranite,two-mica monzogranite,monzogranite,granodiorite,biotite granodiorite,and syenogranite are strongly peraluminous(A/CNK=1.09-1.29),contain peraluminous minerals such as muscovite,have high normative corundum abundances(1.26 wt.%-3.28 wt.%),and have high K2_(O)/Na2O ratios(0.76-1.48),all of which indicate an S-type granite affinity.However,the biotite granodiorite and syenogranite have high Sr(391 ppm-570 ppm)and low Y(3.06 ppm-5.94 ppm)contents,with high Sr/Y(65.8-185.9)ratios,and the two-mica monzogranite,monzogranite,and granodiorite have relatively high Sr(138 ppm-379 ppm)and low Y(3.38 ppm-8.71 ppm)contents,with high Sr/Y ratios(19.1-77.9).All of the analyzed samples have negative zircon eHf(t)values(-41.4 to-20.6)with old two-stage Hf model ages(TDM2(Hf)=2.50-3.76 Ga).Therefore,we infer that the biotite monzogranite is the typical feature of S-type granite that was derived by partial melting of metagraywacke.The monzogranite,two-mica monzogranite,granodiorite,biotite granodiorite,and syenogranite exhibit geochemical characteristics of S-type granite with K-rich adakitic features,and were possibly derived by mixing of melts from clastic crustal materials and ada-kitic magmas.There are voluminous Jurassic igneous rocks in the NE China.By combining our study with the previous researches,this paper infers that the Jurassic magmatism within the Erguna-Xing'an Massif was related to the southward subduction and closure of the Mongol-Okhotsk Ocean;the Early Jurassic magmatism to the east of the Songliao Basin and in the northern North China Cra-ton(NCC)was related to the subduction of the Pacific Plate;however,the Middle-Late Jurassic igne-ous rocks to the west of the Songliao Basin were related to the closure of the Mongol-Okhotsk Ocean and,in the northern NCC,were related to closure of the Mongol-Okhotsk Ocean with an influence from flat-slab subduction of the Pacific Plate.展开更多
基金This research was funded by the NationalKey R&D Program of China(No.2018YFC0603804)the National Natural Science Foundation of China(No.41402060)+3 种基金Science and Technology Project of Department ofEducation,Jilin Province(No.JJKH20200946KJ)the NaturalScience Foundation of Jilin Province(No.20170101201JC)Self-Determined Foundation of Key Laboratory of MineralResources Evaluation in Northeast Asia,Ministry of NaturalResources(Nos.DBY-ZZ-19-13 and DBY-ZZ-19-15)Supported by Graduate Innovation Fund of Jilin University(No.101832020CX211).
文摘The tectonic setting of Jurassic magmatism in the Northeast China(NE China)is unclear.Here,we present new petrological,whole-rock geochemical,zircon U-Pb geochronological,and zircon Lu-Hf isotope data for Jurassic granitoids of the Wulong region,Liaodong Peninsula,NE China.Laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS)zircon U-Pb data indicate that these granitoids were emplaced at 165-156 Ma.The biotite monzogranite,two-mica monzogranite,monzogranite,granodiorite,biotite granodiorite,and syenogranite are strongly peraluminous(A/CNK=1.09-1.29),contain peraluminous minerals such as muscovite,have high normative corundum abundances(1.26 wt.%-3.28 wt.%),and have high K2_(O)/Na2O ratios(0.76-1.48),all of which indicate an S-type granite affinity.However,the biotite granodiorite and syenogranite have high Sr(391 ppm-570 ppm)and low Y(3.06 ppm-5.94 ppm)contents,with high Sr/Y(65.8-185.9)ratios,and the two-mica monzogranite,monzogranite,and granodiorite have relatively high Sr(138 ppm-379 ppm)and low Y(3.38 ppm-8.71 ppm)contents,with high Sr/Y ratios(19.1-77.9).All of the analyzed samples have negative zircon eHf(t)values(-41.4 to-20.6)with old two-stage Hf model ages(TDM2(Hf)=2.50-3.76 Ga).Therefore,we infer that the biotite monzogranite is the typical feature of S-type granite that was derived by partial melting of metagraywacke.The monzogranite,two-mica monzogranite,granodiorite,biotite granodiorite,and syenogranite exhibit geochemical characteristics of S-type granite with K-rich adakitic features,and were possibly derived by mixing of melts from clastic crustal materials and ada-kitic magmas.There are voluminous Jurassic igneous rocks in the NE China.By combining our study with the previous researches,this paper infers that the Jurassic magmatism within the Erguna-Xing'an Massif was related to the southward subduction and closure of the Mongol-Okhotsk Ocean;the Early Jurassic magmatism to the east of the Songliao Basin and in the northern North China Cra-ton(NCC)was related to the subduction of the Pacific Plate;however,the Middle-Late Jurassic igne-ous rocks to the west of the Songliao Basin were related to the closure of the Mongol-Okhotsk Ocean and,in the northern NCC,were related to closure of the Mongol-Okhotsk Ocean with an influence from flat-slab subduction of the Pacific Plate.
