DOI: 10.1007/s00531-016-1310-7
Scopus记录号: 2-s2.0-84961820275
论文题名: Petrogenesis and tectonic implications of the Neoproterozoic Datian mafic–ultramafic dykes in the Panzhihua area, western Yangtze Block, SW China
作者: Yang Y.-J. ; Zhu W.-G. ; Bai Z.-J. ; Zhong H. ; Ye X.-T. ; Fan H.-P.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2017
卷: 106, 期: 1 起始页码: 185
结束页码: 213
语种: 英语
英文关键词: Geochemistry
; Mafic–ultramafic dykes
; Neoproterozoic
; Rodinia
; Southwest China
Scopus关键词: age determination
; continental breakup
; dike
; igneous geochemistry
; mafic rock
; mantle source
; petrogenesis
; petrography
; Proterozoic
; Rodinia
; tectonic setting
; ultramafic rock
; China
; Panzhihua
; Sichuan
; Yangtze Platform
英文摘要: Mafic–ultramafic dykes are important geological markers that can punctuate the onset of crustal extension during the breakup of a continent and provide valuable information on the mantle source. This study reports secondary ion mass spectroscopy zircon and baddeleyite U–Pb ages, elemental and Nd isotopic data for the Datian mafic–ultramafic dykes in the Panzhihua area, western Yangtze Block, SW China. Two kinds of rocks are confirmed: the picritic rock and the dolerite. Based on petrographic and geochemical features, the dolerite dykes are further subdivided into two groups: Group I mafic and Group II mafic dykes, which emplaced at ~760 Ma (zircon U–Pb) and ~800 Ma (zircon and baddeleyite U–Pb), respectively. All samples from the picritic rocks and the Group I mafic rocks show the features of high-Ti and alkaline basaltic magma in composition as well as “humped” trace element patterns, which are similar to those of typical alkaline basalts associated with continental rifts except for the slightly negative Nb–Ta anomalies. The Group II mafic rocks display the features of low-Ti and tholeiitic magma, moderately enriched in LILE and LREE, and characterized by distinctively negative Nb–Ta anomalies. The primary magmas of the picritic rocks and the Group I mafic rocks were generated from ca 25 % partial melting of an OIB-like, Nd isotopically depleted but incompatible elements relatively enriched mantle source within a garnet stable field. The Group II mafic rocks crystallized from crustal contaminated mafic magmas that were derived from a spinel-bearing sub-continental lithospheric mantle source, because of low ratios of La/Yb, Ti/Y and Sm/Yb. Geochemical features suggest that these groups of mafic–ultramafic dykes were formed in a continental rift setting, but derived from different mantle sources. In combination with other Neoproterozoic igneous rocks in the western margin of Yangtze Block, it is suggested that the Datian mafic–ultramafic dykes in the Panzhihua area could have been formed in a multistage continental rift system, most likely related to the proposed mantle superplume, which centered beneath South China at ca. 820 Ma and may have finally triggered the breakup of the supercontinent Rodinia. © 2016, Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961820275&doi=10.1007%2fs00531-016-1310-7&partnerID=40&md5=015031fd703a5965ffe293d0cc1d97a3
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70089
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 99 West Lincheng Road, Guiyang, China; University of Chinese Academy of Sciences, Beijing, China
Recommended Citation:
Yang Y.-J.,Zhu W.-G.,Bai Z.-J.,et al. Petrogenesis and tectonic implications of the Neoproterozoic Datian mafic–ultramafic dykes in the Panzhihua area, western Yangtze Block, SW China[J]. International Journal of Earth Sciences,2017-01-01,106(1)