Petrogenesis of early Paleozoic granitoids in the North Qinling Orogen,Central China:Implications for crustal evolution in an accretionary orogen  

作　　者：Leran Hao Debin Yang Anqi Wang Yikang Quan Xiangyu Yan Shuo Wang 

机构地区：[1]College of Earth Sciences,Jilin University,Changchun 130061,China [2]Key Laboratory of Mineral Resources Evaluation in Northeast Asia(Jilin University),Ministry of Natural Resources,Changchun 130061,China

出　　处：《Geoscience Frontiers》2024年第2期183-201,共19页地学前缘（英文版）

基　　金：This work was financially supported by the Natural Science Foundation of China(grant Nos.42072063,41722204);Program for Jilin University Science and Technology Inovative Research Team(2021TD-05);Postgraduate Innovation Research Program of Jilin University(101832020CX199).

摘　　要：Accretionary orogens are sites of extensive continental crustal growth and modification.The mechanism by which mafic crust is transformed into silicic melts(i.e.,maturation of continental crust)is important for understanding the formation of the continental crust.The North Qinling Orogen(NQO)is a composite orogenic belt and contains an early Paleozoic accretion-dominated orogenic system,which is ideal for investigating continental crustal maturation.We obtained zircon and monazite U–Pb age and O isotope data,zircon Lu–Hf isotope data,and whole-rock major-and trace-element and Sr–Nd isotope data for early Paleozoic granitoids of the NQO.The granitoids are divided into three groups.Group 1 includes the Taiping tonalite(445±3 Ma),the Manziying syenogranite(445±2 Ma),and the Huoshenmiao granodiorite(436±2 Ma).The Taiping and Huoshenmiao plutons have relatively high SiO_(2)contents(68.64–71.67 wt.%)and Na_(2)O/K_(2)O ratios(1.15–4.19),with enrichments in Rb,Ba,Th,and U and depletions in Nb,Ta,P,and Ti,and they are geochemically similar to sodic arc magmas.The Manziying syenogranite is a peraluminous potassic granite with high K_(2)O contents(4.59–5.27 wt.%).Grantioids from Group 1 have similarly depleted Sr–Nd–Hf–O isotopic features(eHf[t]=+5.9 to+8.8;δ^(18)O=3.98‰–5.41‰),indicative of derivation via partial melting of oceanic arc crust,which suggests that partial melting of oceanic arc crust in a subduction system contributes to the generation of continental crust and causes its maturation.Group 2 consists of the Wuduoshan monzogranite(418±2 Ma)and the Sikeshu granodiorite(423±3 Ma).These plutons have relatively high SiO_(2)(65.59–72.06 wt.%),K_(2)O(3.26–4.79 wt.%),and Al2O3(14.65–16.12 wt.%)contents and Sr/Y(33–87)and(La/Yb)N(23–48)ratios.The Wuduoshan monzogranite has positive zircon eHf(t)(+0.4 to+3.1)and uniformδ^(18)O(6.38‰–8.07‰)values,but the Sikeshu granodiorite has more variable isotopic compositions(eHf[t]=-1.9 to+5.0;δ^(18)O=6.37‰–10.60‰).The Wuduoshan

关 键 词：Zircon Hf-O isotopes GRANITE Continental crust Accretionary orogen 

分 类 号：P542.2[天文地球—构造地质学] P534.4[天文地球—地质学]