江南造山带东段齐溪富铌玄武岩的成因及大地构造意义OACHSSCD

The distribution of niobium-rich basalts in the eastern section of the Jiangnan orogenic belt is considered to be genetically related to the breakup of the Rodinia supercontinent,but the output of niobium-rich basalts in Qixi,Zhejiang lacks direct evidence in response to this global event.Therefore,in this paper,the niobium-rich basalt samples in Qixi were systematically collected,and the main and trace elements were analyzed.Combined with zircon U-Pb dating data,the following understandings were obtained:The main elements of niobium-rich basalt in Qixi show obvious lithological differentiation characteristics.The rare earth elements show a right-leaning distribution pattern of light rare earth enrichment and heavy rare earth loss,with obvious negative Eu anomaly and enrichment of high field strength elements such as Nb,Ta and Ti,which is consistent with the geochemical characteristics of subduction zone arc magmatic rocks.Chronological result is 769.1±4.5 Ma,reflecting that the basalt was formed in the Neoproterozoic Nanhua period.The tectonic environment discrimination shows that the Qixi niobium-rich basalt was formed in the subduction-extension transition environment after the combination of the Yangtze block and the Cathaysia block in the late Neoproterozoic,which is the magmatic response product of crust-mantle interaction and subduction-extension tectonic transformation.