Geochemistry, Sr-Nd-Pb Isotopic Compositions and Zircon U-Pb Geochronology of Neoproterozoic Mafic Dyke in the Douling Complex, South Qinling Belt, China  

作　　者：Tong Li Liang Liu Xiao-Ying Liao Yong-Sheng Gai Tuo Ma Chao Wang 

机构地区：[1]State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi'an 710069,China

出　　处：《Journal of Earth Science》2020年第2期237-248,共12页地球科学学刊（英文版）

基　　金：We are grateful to three anonymous reviewers for their constructive comments and suggestions;This study was financially supported by the National Nature Science Foundation of China(Nos.41572049,41902050,41430209,41421002);the Major State Basic Research Development Projects(No.2015CB856103);the State Key Laboratory of Continental Dynamics,Northwest University.

摘　　要：Mafic dyke swarm is widely developed in Proterozoic continental lithosphere.The Gangou diabase dyke from the Xixia area,intruded into the Douling complex of the South Qinling belt,yields zircon UPb age of 731 Ma.It has low SiO2 content(49.02 wt.%-49.37 wt.%)and Mg^#(34.0–37.7)and shows characteristics of subalkaline tholeiite series.They show highΣREE(155.5×10^-6–184.7×10^-6),weak negative Eu anomaly(δEu=0.88-0.93),slight depletion of Nb and Ta,and enrichment of LILE.Their major and trace element,Sr-Nd-Pb isotope and clinopyroxene compositions indicate that it originated from the partial melting of the asthenospheric mantle within-plate extension setting and was slightly contaminated by crust compositions.The similarities of formation age,petrogenesis,source characteristic and tectonic setting for Gangou diabase with mafic dykes in Wudang Block and mafic volcanic rocks in Yaolinghe Group indicate that the South Qinling belt underwent strong continental extension in Neoproterozoic during 796–685 Ma most likely correspondence to the breaking-up of the Rodinia supercontinent.

关 键 词：Douling COMPLEX DIABASE DYKE LA-ICP-MS zircon U-Pb dating SR-ND-PB isotope RODINIA SUPERCONTINENT break-up 

分 类 号：P618.31[天文地球—矿床学] P597[天文地球—地质学] P548