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The Bikou basalts in the northwestern Yangtze block, South China: Remnants of 820-810 Ma continental flood basalts?

2008; Geological Society of America; Volume: 120; Issue: 11-12 Linguagem: Inglês

10.1130/b26310.1

1943-2674

Xuan‐Ce Wang, X.-H. Li, W.-X. Li, Zheng‐Xiang Li, Yan Liu, Yue‐Heng Yang, Xiujuan Liang, Xiaoxian Tu,

earthquake and tectonic studies

Research Article| November 01, 2008 The Bikou basalts in the northwestern Yangtze block, South China: Remnants of 820–810 Ma continental flood basalts? Xuan-Ce Wang; Xuan-Ce Wang 1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China 2Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Xian-Hua Li; Xian-Hua Li † 1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China 2Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China †E-mail: lixh@gig.ac.cn. Search for other works by this author on: GSW Google Scholar Wu-Xian Li; Wu-Xian Li 3Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Zheng-Xiang Li; Zheng-Xiang Li 4Institute for Geoscience Research, Department of Applied Geology, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia Search for other works by this author on: GSW Google Scholar Ying Liu; Ying Liu 5Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Yue-Heng Yang; Yue-Heng Yang 6State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China Search for other works by this author on: GSW Google Scholar Xi-Rong Liang; Xi-Rong Liang 7Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Xiang-Lin Tu Xiang-Lin Tu 7Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Author and Article Information Xuan-Ce Wang 1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China 2Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Xian-Hua Li † 1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China 2Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Wu-Xian Li 3Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Zheng-Xiang Li 4Institute for Geoscience Research, Department of Applied Geology, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia Ying Liu 5Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Yue-Heng Yang 6State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China Xi-Rong Liang 7Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Xiang-Lin Tu 7Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China †E-mail: lixh@gig.ac.cn. Publisher: Geological Society of America Received: 14 Aug 2007 Revision Received: 16 Jan 2008 Accepted: 21 Jan 2008 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2008 Geological Society of America GSA Bulletin (2008) 120 (11-12): 1478–1492. https://doi.org/10.1130/B26310.1 Article history Received: 14 Aug 2007 Revision Received: 16 Jan 2008 Accepted: 21 Jan 2008 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Xuan-Ce Wang, Xian-Hua Li, Wu-Xian Li, Zheng-Xiang Li, Ying Liu, Yue-Heng Yang, Xi-Rong Liang, Xiang-Lin Tu; The Bikou basalts in the northwestern Yangtze block, South China: Remnants of 820–810 Ma continental flood basalts?. GSA Bulletin 2008;; 120 (11-12): 1478–1492. doi: https://doi.org/10.1130/B26310.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Mantle plume or superplume activities have often been invoked as a cause for the breakup of the Neoproterozoic supercontinent Rodinia. However, associated Neoproterozoic continental flood basalts, a requisite product of mantle plume ac tivities, have rarely been identified. New sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon ages, geochemical, and Hf-Nd isotopic data are reported here for the Bikou Group basalts, the largest Neoproterozoic volcanic units in the northwestern Yangtze block, South China. The Bikou basalts are mainly tholeiitic in composition, and they can be stratigraphically subdivided into the lower and upper groups. SHRIMP U-Pb zircon dating of intercalated rhyolites indicates that the lower and upper group basalts were erupted at 821 ± 7 Ma and 811 ± 12 Ma, respectively. The two basalt groups define two populations on most elemental and isotopic diagrams. The lower group basalts display strong sub-continental lithospheric mantle affinities and large variable ϵNd(t) and ϵHf(t) values that correlate negatively with Th/Ta and positively with MgO. The upper group basalts, on the other hand, show ocean-island basalt (OIB) affinities and highly positive ϵHf(t) and ϵNd(t) values. Numerical modeling indicates that the lower and upper group basalts were formed at melting temperatures of >1350 °C and >1450 °C and mantle potential temperatures of 1400–1488 °C and 1550 ± 30 °C, respectively. Thus, the upper group basalts were derived from an anomalously hot asthenosphere mantle, ~160 °C hotter than the contemporary ambient mid-ocean-ridge basalt (MORB) source mantle. Our results are at clear variance with the alternative tectonic model that the Bikou basalts were part of a continental magmatic arc. Our work suggests that the Bikou basalts are likely the remnants of Neoproterozoic continental flood basalts that formed in response to a mantle plume starting ca. 825 Ma during the breakup of the supercontinent Rodinia. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.