| 1 | Petrogenesis of Jurassic Granitoids on Liaodong Peninsula,Northeast China:Constraints on the Evolution of the Mongol-Okhotsk and Pacific Tectonic Regimes显示文摘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. | Jinyu Li Ye Qian Leontine Tekoumc Changji Zhao Jinlei Sun Tao Zheng Fengyue Sun Yanjie Shen | 2021 | Journal of Earth Science2021，32，1： | 2 |
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