Dupal Anomaly and Identification using Nd-Hf Isotopes

作     者：TIAN Ye XU Jifeng LIU Xijun TIAN Ye;XU Jifeng;LIU Xijun

作者机构：School of Earth Science and Resourcesand State Key Laboratory of Geological Processes and Mineral ResourcesChina University of GeosciencesBeijing 100083China Guangxi Key Laboratory of Hidden Metallic Ore Deposits ExplorationCollege of Earth SciencesGuilin University of TechnologyGuilinGuangxi 541004China 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2022年第96卷第2期

页      面：416-429页

核心收录：

学科分类：070902[理学-地球化学] 0709[理学-地质学] 07[理学] 

基　　金：funded by the National Key Research and Development Project of China (Project 2020YFA0714800) 

主　　题：Dupal anomaly LLSVPs Pb isotope Nd-Hf isotope mantle heterogeneity 

摘      要：The Dupal anomaly has attracted widespread attention since being discovered and is regarded as the most direct manifestation of mantle inhomogeneity at present. From the initially defined anomalies limited to the southern hemisphere to the global scale, the criteria for identifying anomalies defined by Pb isotopes have also been adjusted, providing an important method and reference for the study of the mantle evolution. Pearce and Peate(1995) proposed the method of NdHf isotope and element ratio to identify the Dupal anomaly. The Nd-Hf method also offers a possible way to discriminate the mantle region of arc magmatism through the correction of Nd in the subduction process. This paper introduces the concepts and determination methods of the Dupal anomaly, and reports new Hf isotopic data of MORB-type rocks with Dupal signature in the several Tethys ophiolites. Our results of Nd-Hf method are in good agreement with those of previous Pb isotope identification. Moreover, origins and their controversy of Dupal anomaly are reviewed, and possible internal connections between Dupal anomalies and the two Large Low Shear Velocity Provinces(LLSVPs) in the lower mantle are discussed in depth. Further studies on origin and evolution of the Dupal anomaly are suggested, especially using integrated approach of Hf-Nd and Pb isotopes.