Petrogenesis and tectonic implications of the Early Cretaceous Dagushan adakitic porphyries in the Anshan area,North China Craton

作     者：Xiaohui Sun Haoshu Tang Yan Luan Xiaohui Sun;Haoshu Tang;Yan Luan

作者机构：Key Laboratory of Western China’s Mineral Resources and Geological EngineeringMOESchool of Earth Science and ResourcesChang’an UniversityXi'an 710054China State Key Laboratory of Ore Deposit GeochemistryInstitute of GeochemistryChinese Academy of SciencesGuiyang 550081China 

出 版 物：《Acta Geochimica》 (地球化学学报（英文）)

年 卷 期：2022年第41卷第1期

页      面：24-38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：jointly supported by the National Natural Science Foundation of China(Nos.41872085,41503035) the Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2019JM-160,2017JM4006) Fundamental Research Funds for the Central Universities(300102271201) 

主　　题：Diorite porphyry Adakite Lower crust Delamination NCC 

摘      要：The eastern part of the North China Craton suffered significant lithospheric thinning since the Mesozoic,and petrogenesis of the Dagushan adakitic diorite porphyries provides an excellent opportunity to investigate the lithospheric thinning mechanism and geodynamic *** zircon LA-ICP-MS U–Pb geochronology reveals that the representative Dagushan adakitic porphyry was formed at 120.5±0.5 *** Dagushan diorite porphyries are characterized by the relatively high contents of SiO_(2)(64.25–65.70 wt%),Al_(2) O_(3)(15.00–15.38 wt%),Sr(333–491 ppm),low contents of Y(6.50–10.3 ppm),and Yb(0.57–0.85 ppm),and resultant high Sr/Y(47–57)and La/Yb(37–55)ratios,exhibiting geochemical characteristics of typical ***,the relatively high Mg O contents(MgO=2.23–2.29 wt%)and Mg numbers(Mg^(#)-=54–56)of the Dagushan adakitic rocks imply that the pristine adakitic magma interacted with mantle ***,the zircon Hf isotopic signatures(εHf(t)=-19.0 to-28.0;TDM2=2378–2944 Ma)suggest an ancient lower crustal ***,it is proposed that the Dagushan adakitic rock was probably generated by partial melting of delaminated lower crust which was triggered by the Tan-Lu Fault Zone,and the interaction of pristine adakitic magma with mantle peridotite during the ascent finally generated the Dagushan high Mg^(#)adakitic *** is suggested that delamination was an important mechanism for lithospheric thinning of the NCC.