中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
Geochemical and Sr-Nd-Pb isotopic constraints on the origin and petrogenesis of Paleozoic lamproites in the southern Yangtze Block, South China

文献类型:期刊论文

作者Xiang, Lu3,4; Zheng, Jianping4; Zhai, Mingguo2,3; Siebel, Wolfgang1
刊名CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
出版日期2020-03-12
卷号175期号:4页码:18
关键词Sr-Nd-Pb isotopes Subcontinental lithospheric mantle Mantle metasomatism Petrogenesis Baifen lamproites Yangtze Block
ISSN号0010-7999
DOI10.1007/s00410-020-1668-1
英文摘要Lamproites and kimberlites are natural probes of the subcontinental lithospheric mantle providing insights into the Earth's continental lithosphere. Whole-rock major-, trace-element and Sr-Nd-Pb isotopic compositions of the Paleozoic (similar to 253 Ma) lamproite dikes from the Baifen zone of the Zhenyuan area in southeastern Guizhou Province (in the southern Yangtze Block, South China) are presented. The Baifen lamproites are characterized by high MgO (7.84-14.1 wt%), K2O (3.94-5.07 wt%) and TiO2 (2.69-3.23 wt%) contents, low SiO2 (41.3-45.7 wt%), Na2O (0.21-0.28 wt%) and Al2O3 (6.10-7.20 wt%) contents. All lamproites have elevated Cr (452-599 ppm) and Ni (485-549 ppm) abundances, as well as high Ba (1884-3589 ppm), La (160-186 ppm), Sr (898-1152 ppm) and Zr (532-632 ppm) concentrations. They show uniform REE distribution patterns that are strongly enriched in light REEs relative to heavy REEs [(La/Yb)(N) = 71.1-87.6], and exhibit OIB-like geochemical features with obvious enrichment of both LILEs and HFSEs in the primitive mantle-normalized multi-element distribution diagram. Moderately radiogenic Sr (Sr-87/Sr-86(i) = 0.706336-0.707439), unradiogenic Nd (Nd-143/Nd-144(i) = 0.511687-0.511704 and epsilon(Nd)(t) = - 12.2 to - 11.9), and low initial Pb (Pb-206/Pb-204(i) = 16.80-16.90, Pb-207/Pb-204(i) = 15.34-15.35 and Pb-208/Pb-204(i) = 37.43-37.70) isotopic compositions are obtained from the rocks. They yield old model ages of T-DM(Nd) = 1.48-1.54 Ga. These signatures suggest that the Baifen lamproite magmas are alkaline, ultrapotassic and ultramafic in character and mainly represent mantle-derived primary melts, which have undergone insignificant crustal contamination and negligible fractional crystallization. The Baifen lamproites originated from a veined metasomatized lithospheric mantle source. We envisage that they were derived by partial melting of old, mineralogically complex metasomatic vein assemblages in the subcontinental lithospheric mantle beneath the southern Yangtze Block. The source region experienced ancient mantle metasomatism with complex modification by enriched fluids and melts. The metasomatic agents are most likely to originate from pre-existing slab subduction beneath the southeastern margin of the Yangtze Block. Tectonically, the Baifen lamproites were emplaced at the southern margin of the Yangtze Block, and they formed in an intraplate extensional setting, showing an anorogenic affinity. In terms of time and space, the genesis of Baifen lamproites is presumably related to the Emeishan large igneous province. The Emeishan mantle plume is suggested as an effective mechanism for rapid extension and thinning of the lithosphere, followed by decompression melting of the subcontinental lithospheric mantle. Combined with the thermal perturbation from asthenospheric upwelling induced by the Emeishan mantle plume, the lamproite magmas, representing small volume and limited partial melts of ancient enriched mantle lithosphere, arose. We propose that the generation of the Baifen lamproite dikes probably was a consequence of the far-field effects of the Emeishan mantle plume.
WOS关键词EMEISHAN FLOOD BASALTS ; ULTRAPOTASSIC VOLCANIC-ROCKS ; EASTERN DHARWAR CRATON ; LARGE IGNEOUS PROVINCE ; MANTLE SOURCE ; TRACE-ELEMENT ; CRUSTAL CONTAMINATION ; LITHOSPHERIC MANTLE ; MESOPROTEROZOIC LAMPROITES ; ULTRAMAFIC LAMPROPHYRES
资助项目National Natural Science Foundation of China[NSFC 41520104003] ; National Natural Science Foundation of China[41930215] ; China Geological Survey[12120114054201] ; China Geological Survey[12120114016801] ; Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan)[CUGCJ1709]
WOS研究方向Geochemistry & Geophysics ; Mineralogy
语种英语
WOS记录号WOS:000519344100001
出版者SPRINGER
资助机构National Natural Science Foundation of China ; National Natural Science Foundation of China ; China Geological Survey ; China Geological Survey ; Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) ; Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; China Geological Survey ; China Geological Survey ; Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) ; Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; China Geological Survey ; China Geological Survey ; Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) ; Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; China Geological Survey ; China Geological Survey ; Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) ; Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan)
源URL[http://ir.iggcas.ac.cn/handle/132A11/95583]  
专题地质与地球物理研究所_岩石圈演化国家重点实验室
通讯作者Zheng, Jianping
作者单位1.Albert Ludwigs Univ Freiburg, Inst Geo & Umweltnat Wissensch, Albertstr 23b, D-79104 Freiburg, Germany
2.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China
3.Zhejiang Univ, Sch Earth Sci, Hangzhou 310027, Peoples R China
4.China Univ Geosci, Sch Earth Sci, State Key Lab Geol Proc & Mineral Resources, Wuhan 430074, Peoples R China
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Xiang, Lu,Zheng, Jianping,Zhai, Mingguo,et al. Geochemical and Sr-Nd-Pb isotopic constraints on the origin and petrogenesis of Paleozoic lamproites in the southern Yangtze Block, South China[J]. CONTRIBUTIONS TO MINERALOGY AND PETROLOGY,2020,175(4):18.
APA Xiang, Lu,Zheng, Jianping,Zhai, Mingguo,&Siebel, Wolfgang.(2020).Geochemical and Sr-Nd-Pb isotopic constraints on the origin and petrogenesis of Paleozoic lamproites in the southern Yangtze Block, South China.CONTRIBUTIONS TO MINERALOGY AND PETROLOGY,175(4),18.
MLA Xiang, Lu,et al."Geochemical and Sr-Nd-Pb isotopic constraints on the origin and petrogenesis of Paleozoic lamproites in the southern Yangtze Block, South China".CONTRIBUTIONS TO MINERALOGY AND PETROLOGY 175.4(2020):18.

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来源:地质与地球物理研究所

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