Nature and evolution of lithospheric mantle beneath the southern Ethiopian rift zone: evidence from petrology and geochemistry of mantle xenoliths

doi:10.1007/s00531-016-1342-z

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 > 岩石圈演化国家重点实验室

	Nature and evolution of lithospheric mantle beneath the southern Ethiopian rift zone: evidence from petrology and geochemistry of mantle xenoliths
	Alemayehu, Melesse 1,2; Zhang, Hong-Fu 1,3; Sakyi, Patrick Asamoah 4
刊名	INTERNATIONAL JOURNAL OF EARTH SCIENCES
	2017-04-01
卷号	106 期号:3 页码:939-958
关键词	Dillo-megado Mantle Xenoliths Depletion Enrichment Sr-nd-hf Isotopes
ISSN号	1437-3254
DOI	10.1007/s00531-016-1342-z
文献子类	Article
英文摘要	Mantle xenoliths hosted in Quaternary basaltic lavas from the Dillo and Megado areas of the southern Ethiopian rift are investigated to understand the geochemical composition and associated processes occurring in the lithospheric mantle beneath the region. The xenoliths are comprised of predominantly spinel lherzolite with subordinate harzburgite and clinopyroxenite. Fo content of olivine and Cr# of spinel for peridotites from both localities positively correlate and suggest the occurrence of variable degrees of partial melting and melt extraction. The clinopyroxene from lherzolites is both LREE depleted (La/Sm-(N) = 0.11-0.37 x Cl) and LREE enriched (La/Sm-(N) = 1.88-15.72 x Cl) with flat HREEs (Dy/Lu-(N) = 0.96-1.31 x Cl). All clinopyroxene from the harzburgites and clinopyroxenites exhibits LREE-enriched (La/Sm-(N) = 2.92-27.63.1 x Cl and, 0.45 and 1.38 x Cl, respectively) patterns with slight fractionation of HREE. The Nd-143/Nd-144 and Hf-176/Hf-177 ratios of clinopyroxene from lherzolite range from 0.51291 to 0.51370 and 0.28289 to 0.28385, respectively. Most of the samples define ages of 900 and 500 Ma on Sm-Nd and Lu-Hf reference isochrons, within the age range of Pan-African crustal formation. The initial Nd and Hf isotopic ratios were calculated at 1, 1.5, 2 and 2.5 Ga plot away from the trends defined by MORB, DMM and E-DMM which were determined from southern Ethiopian peridotites, thus indicating that the Dillo and Megado xenoliths could have been produced by melt extraction from the asthenosphere during the Pan-African orogenic event. There is no significant difference in Sr-87/Sr-86 ratios between the depleted and enriched clinopyroxene. This suggests that the melts that caused the enrichment of the clinopyroxene are mainly derived from the depleted asthenospheric mantle from which the xenoliths are extracted. Largely, the mineralogical and isotopic compositions of the xenoliths show heterogeneity of the CLM that could have been produced from various degrees of melt extraction, followed by metasomatism.
WOS关键词	SPINEL PERIDOTITE XENOLITHS ; EAST-AFRICAN RIFT ; NORTH CHINA CRATON ; IONIZATION MASS-SPECTROMETRY ; OCEANIC UPPER-MANTLE ; LA-ICP-MS ; CARBONATITE METASOMATISM ; DEPLETED MANTLE ; TRACE-ELEMENTS ; CONTINENTAL LITHOSPHERE
WOS研究方向	Geology
语种	英语
出版者	SPRINGER
WOS记录号	WOS:000398931600008
资助机构	Chinese Academy of Sciences(2014FFBZ003) ; Chinese Academy of Sciences(2014FFBZ003) ; National Science Foundation of China(41450110429 ; National Science Foundation of China(41450110429 ; 91414301) ; 91414301) ; Chinese Academy of Sciences(2014FFBZ003) ; Chinese Academy of Sciences(2014FFBZ003) ; National Science Foundation of China(41450110429 ; National Science Foundation of China(41450110429 ; 91414301) ; 91414301) ; Chinese Academy of Sciences(2014FFBZ003) ; Chinese Academy of Sciences(2014FFBZ003) ; National Science Foundation of China(41450110429 ; National Science Foundation of China(41450110429 ; 91414301) ; 91414301) ; Chinese Academy of Sciences(2014FFBZ003) ; Chinese Academy of Sciences(2014FFBZ003) ; National Science Foundation of China(41450110429 ; National Science Foundation of China(41450110429 ; 91414301) ; 91414301)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/52969]
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	Alemayehu, Melesse; Zhang, Hong-Fu
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, POB 9825, Beijing 100029, Peoples R China 2.Addis Ababa Sci & Technol Univ, Sch Earth Sci & Min Engn, Dept Earth Sci, POB 16417, Addis Ababa, Ethiopia 3.Northwest Univ, State Key Lab Continental Dynam, Dept Geol, Xian 710069, Peoples R China 4.Univ Ghana, Dept Earth Sci, POB LG 58, Legon, Ghana
推荐引用方式 GB/T 7714	Alemayehu, Melesse,Zhang, Hong-Fu,Sakyi, Patrick Asamoah. Nature and evolution of lithospheric mantle beneath the southern Ethiopian rift zone: evidence from petrology and geochemistry of mantle xenoliths[J]. INTERNATIONAL JOURNAL OF EARTH SCIENCES,2017,106(3):939-958.
APA	Alemayehu, Melesse,Zhang, Hong-Fu,&Sakyi, Patrick Asamoah.(2017).Nature and evolution of lithospheric mantle beneath the southern Ethiopian rift zone: evidence from petrology and geochemistry of mantle xenoliths.INTERNATIONAL JOURNAL OF EARTH SCIENCES,106(3),939-958.
MLA	Alemayehu, Melesse,et al."Nature and evolution of lithospheric mantle beneath the southern Ethiopian rift zone: evidence from petrology and geochemistry of mantle xenoliths".INTERNATIONAL JOURNAL OF EARTH SCIENCES 106.3(2017):939-958.