DOI: 10.1016/j.epsl.2018.02.040
Scopus记录号: 2-s2.0-85042904129
论文题名: Geochemical nature of sub-ridge mantle and opening dynamics of the South China Sea
作者: Zhang G.-L. ; Luo Q. ; Zhao J. ; Jackson M.G. ; Guo L.-S. ; Zhong L.-F.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 489 起始页码: 145
结束页码: 155
语种: 英语
英文关键词: continental rifting
; Dupal anomaly
; Hainan plume
; lower continental crust
; South China Sea
Scopus关键词: Geochemistry
; Hafnium
; Isotopes
; Lead
; Strontium
; Tectonics
; Trace elements
; Continental crusts
; Continental rifting
; DUPAL anomalies
; Hainan plume
; South China sea
; Basalt
; continental crust
; isotopic composition
; mantle convection
; mantle plume
; mantle source
; rifting
; Pacific Ocean
; South China Sea
英文摘要: The Indian-type mantle (i.e., above the north hemisphere reference line on the plot of 208Pb/204Pb vs. 206Pb/204Pb) has been considered as a “Southern Hemisphere” geochemical signature, whose origin remains enigmatic. The South China Sea is an extensional basin formed after rifting of the Euro-Asia continent in the Northern Hemisphere, however, the geochemical nature of the igneous crust remains unexplored. For the first time, IODP Expedition 349 has recovered seafloor basalts covered by the thick sediments in the Southwest sub-basin (Sites U1433 and U1434) and the East sub-basin (Site U1431). The Southwest sub-basin consists of enriched (E)-MORB type basalts, and the East sub-basin consists of both normal (N)-MORB-type and E-MORB-type basalts based on trace element compositions. The basalts of the two sub-basins are Indian-type MORBs based on Sr–Nd–Pb–Hf isotope compositions, and the Southwest sub-basin basalts show isotopic compositions (i.e., 206Pb/204Pb of 17.59–17.89) distinctly different from the East sub-basin (i.e., 206Pb/204Pb of 18.38–18.57), suggesting a sub-basin scale mantle compositional heterogeneity and different histories of mantle compositional evolution. Two different enriched mantle end-members (EM1 and EM2) are responsible for the genesis of the Indian-type mantle in the South China Sea. We have modeled the influences of Hainan mantle plume and lower continental crust based on Sr–Nd–Pb–Hf isotope compositions. The results indicate that the influence of Hainan plume can explain the elevated 206Pb/204Pb of the East sub-basin basalts, and the recycling of lower continental crust can explain the low 206Pb/204Pb of the Southwest sub-basin basalts. Based on the strong geochemical imprints of Hainan plume in the ridge magmatism, we propose that the Hainan plume might have promoted the opening of the South China Sea, during which the Hainan plume contributed enriched component to the sub-ridge mantle and caused thermal erosion and return of lower continental crust to the convective mantle. These results imply an in situ origin of the Indian-type mantle that can help understand the genesis of the “Southern Hemisphere” geochemical anomaly in the Northern Hemispheric extensional basin. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109957
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
There are no files associated with this item.
作者单位: Key Laboratory of Marine Geology and Environment, Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China; Radiogenic Isotope Laboratory, Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland 4072, Australia; Department of Earth Sciences, University of California Santa Barbara, Santa Barbara, CA 93106, United States; The Institute of Crustal Dynamics, China Earthquake Administration, Beijing, 100085, China; School of Marine Sciences, Sun Yat-Sen University, Guang Zhou, 510275, China
Recommended Citation:
Zhang G.-L.,Luo Q.,Zhao J.,et al. Geochemical nature of sub-ridge mantle and opening dynamics of the South China Sea[J]. Earth and Planetary Science Letters,2018-01-01,489