Origin of Late Cenozoic Abaga-Dalinuoer basalts, eastern China: Implications for a mixed pyroxenite-peridotite source related with deep subduction of the Pacific slab

doi:10.1016/j.gr.2016.05.014

CORC > 地质与地球物理研究所 > 中国科学院地质与地球物理研究所 > 中国科学院新生代地质与环境重点实验室

	Origin of Late Cenozoic Abaga-Dalinuoer basalts, eastern China: Implications for a mixed pyroxenite-peridotite source related with deep subduction of the Pacific slab
	Zhang, Maoliang 1,2; Guo, Zhengfu 1
刊名	GONDWANA RESEARCH
	2016-09-01
卷号	37 页码:130-151
关键词	Continental intraplate basalts Olivine Mixed pyroxenite-peridotite source Deep subduction of the Pacific slab Eastern China
DOI	10.1016/j.gr.2016.05.014
文献子类	Article
英文摘要	Continental intraplate basalts (15.42-0.16 Ma) from Abaga-Dalinuoer volcanic field (ADVF) in central Inner Mongolia of eastern China, as a part of Cenozoic volcanic province along eastern margin of the Eurasian continent, provide a good opportunity to explore potential links between deep subduction of the Pacific slab and continental intraplate volcanism. In this study, we report an integrated dataset of whole-rock K-Ar ages, major and trace elements and Sr-Nd-Pb isotopes, and olivine major and minor elements for the Abaga-Dalinuoer basalts (ADBs), and propose that mantle source lithology of the ADB magmas may consist of both pyroxenite and peridotite. The ADBs display low SiO2 (423-502 wt.%), high MgO (7.3-11.4 wt%) and moderate K2O + Na2O (3.8-6.4 wt.%), and can be subdivided into basanites, alkali basalts and tholeiitic basalts that are all characterized by ocean island basalt (OIB)-like rare earth elements (REE) and enrichment in both large ion lithosphile elements (LILE) and high field strength elements (HFSE). Olivine phenocrysts have higher Ni and Fe/Mn and lower Mn, Ca and Ca/Fe relative to those from peridotite melts, but exhibit clearly lower Ni contents (<2500 ppm) compared with expected Ni range (>3000 ppm) for olivines crystallized from olivine-free pyroxenite melts. Estimated compositions of the ADB primary magmas, together with olivine compositions, suggest an iron-rich mantle source related with silica deficient pyroxenite that is most likely derived from deeply subducted Pacific oceanic crust. Additionally, peridotite and recent subducted sediments are also required to account for high Ni and MgO in primary magmas together with their trace elements and Sr-Nd-Pb isotope systematics. We suggest that a mixed pyroxenite-peridotite source lithology can better match observed whole-rock and olivine signatures in the ADB, compared with either peridotite only or olivine-free pyroxenite only source lithology. In our model, pyroxenite melts would either react with or mechanically mix with peridotite, and the proportion of pyroxenite melts may range from 30% to 45% for mechanical mixing scenario. A continuous spectrum from tholeiitic to alkali melts revealed by melt-peridotite reaction experiment can explain formation of primary magmas of basanites, alkali basalts and tholeiitic basalts by increasing melting degree of a similar mantle source. Relatively higher Pb-206/Pb-24 of the ADB may suggest more significant role of recent (<0.5 Ga) subducted Pacific oceanic materials, in contrast to other Cenozoic basalts in eastern China (e.g., Changbai basalts) that exhibit varying contributions from ancient (>1.5 Ga) subducted continental sediments. We emphasize that coupled geochemical and geodynamic links (i.e., subduction polarity) between deeply subducted Pacific slab and continental intraplate volcanism in eastern China may exist, which directly support the involvement of deeply subducted Pacific materials in petrogenesis of the ADB. From the perspective of plate motion kinetics, decompression partial melting of upwelling fragmented Pacific slab (silica-deficient pyroxenite + recent subducted sediments) may be triggered by rollback of deeply subducted Pacific slab during Late Cenozoic times. Continental intraplate volcanism in the ADVF generally started with termination of opening of the Japan Sea, suggesting that deep subduction of the Pacific slab may have been an important geodynamic mechanism responsible for tectono-magmatic evolution of northeastern Asia.
WOS关键词	OCEAN-ISLAND BASALTS ; PARTIAL MELTING EXPERIMENTS ; MANTLE TRANSITION ZONE ; ASIAN OROGENIC BELT ; LITHOSPHERE-ASTHENOSPHERE INTERACTION ; IONIZATION MASS-SPECTROMETRY ; TRACE-ELEMENT COMPOSITIONS ; ND-PB ISOTOPE ; NORTH CHINA ; INNER-MONGOLIA
WOS研究方向	Geology
语种	英语
WOS记录号	WOS:000384703200009
资助机构	Chinese Academy of Sciences(XDB03010600) ; Chinese Academy of Sciences(XDB03010600) ; National Natural Science Foundation of China(41572321) ; National Natural Science Foundation of China(41572321) ; Chinese Academy of Sciences(XDB03010600) ; Chinese Academy of Sciences(XDB03010600) ; National Natural Science Foundation of China(41572321) ; National Natural Science Foundation of China(41572321)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/53313]
专题	地质与地球物理研究所_中国科学院新生代地质与环境重点实验室
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Cenozo Geol & Environm, Beijing 100029, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Maoliang,Guo, Zhengfu. Origin of Late Cenozoic Abaga-Dalinuoer basalts, eastern China: Implications for a mixed pyroxenite-peridotite source related with deep subduction of the Pacific slab[J]. GONDWANA RESEARCH,2016,37:130-151.
APA	Zhang, Maoliang,&Guo, Zhengfu.(2016).Origin of Late Cenozoic Abaga-Dalinuoer basalts, eastern China: Implications for a mixed pyroxenite-peridotite source related with deep subduction of the Pacific slab.GONDWANA RESEARCH,37,130-151.
MLA	Zhang, Maoliang,et al."Origin of Late Cenozoic Abaga-Dalinuoer basalts, eastern China: Implications for a mixed pyroxenite-peridotite source related with deep subduction of the Pacific slab".GONDWANA RESEARCH 37(2016):130-151.