干旱区生态环境知识资源中心(Arid): Metasomatized peridotite xenoliths from the cretaceous rift-related Natash volcanics and their bearing on the nature of the lithospheric mantle beneath the southern part of the Eastern Desert of Egypt

Arid

DOI	10.1016/j.lithos.2020.105642
	Metasomatized peridotite xenoliths from the cretaceous rift-related Natash volcanics and their bearing on the nature of the lithospheric mantle beneath the southern part of the Eastern Desert of Egypt
	Abe, Natsue; Surour, Adel A.; Madani, Ahmed A.; Arai, Shoji
通讯作者	Surour, AA
来源期刊	LITHOS
ISSN	0024-4937
EISSN	1872-6143
出版年	2020
卷号	370
英文摘要	Highly carbonated mantle xenoliths have been found in rift-related alkaline basalts at the Wadi Natash area in the southern part of the Eastern Desert of Egypt. Although all olivine and most orthopyroxene was replaced by carbonate and/or quartz, textural and mineral chemical features show that they are plagioclase-free spinel peridotites (lherzolite to harzburgite). Cr and Mg numbers (Cr#, Mg#) of Cr-spinel vary from 0.06 to 0.45 and 0.73 to 0.81, respectively. The correlation between Cr# and Mg# of the Cr-spine) in the studied xenoliths is weakly negative and its TiO2 content is slightly higher than in abyssal peridotite that was not affected by melt injection. The chemistry of ortho- and clinopyroxene suggests enstatite and chromian diopside compositions, respectively, with distinct signatures of a sub-continental mantle source. In particular, the Na2O contents (>1.0 wt%) and Al-VI/Al-IV ratios (12-2.6) of chromian diopside suggest such an origin. Two-pyroxene geothermome try indicates a temperature of about 900 degrees C, which is slightly lower than that of ordinary spinel peridotite xenoliths from other rift zones. It is evident that the studied peridotite xenoliths had experienced mantle processes (e.g. decompression melting, magma upwelling and metasomatism) at higher pressure than abyssal peridotites. The trace-element chemistry of clinopyroxene, e.g. high LREE/HREE ratios {(Ce/Yb)(n) = 7), high LREE contents (>3.6 ppm and up to 30.0 ppm Ce) and high Sr between >85.6 ppm and 466 ppm, indicates metasomatic alteration of the peridotite. Clinopyroxene in one sample has very low Ti/Eu and high LREE/HREE ratios. Clinopyroxene with (Ce/Yb)(n) higher than 3-4 and Ti/Eu ratio lower than 1500 may have experienced carbonatite or carbonate-rich melt metasomatism prior to their incorporation into the host basalt. The basalt itself is almost devoid of any carbonatization and hence the studied mantle peridotites were carbonatized before the generation of the basaltic magma but following an earlier event of K-metasomatism as indicated by the presence of phlogopite. The studied peridotites from the Wadi Natash area were altered by a carbonate-rich melt during a rifting stage. The results of the present paper indicate that the Natash basalts with their peridotite xenoliths extruded along transversal fractures of the NW-trending Nuqra-Kom Ombo-Kharit continental rift on its western shoulder in the south Eastern Desert of Egypt. (C) 2020 Elsevier B.V. All rights reserved.
英文关键词	Cretaceous Natash basalt Peridotite mantle xenoliths Carbonate metasomatism Abyssal sub-continental mantle
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000558896300027
WOS关键词	WESTERN SAUDI-ARABIA ; OCEANIC UPPER-MANTLE ; SPINEL PERIDOTITE ; CARBONATITE METASOMATISM ; GEOCHEMICAL CONSTRAINTS ; OXIDATION-STATE ; ORTHO-PYROXENE ; TRACE-ELEMENT ; LOWER CRUST ; RED-SEA
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/325583
作者单位	[Abe, Natsue] Japan Agcy Marine Earth Sci & Technol JAMSTEC, Res & Dev Ctr Ocean Drilling Sci, Yokosuka, Kanagawa, Japan; [Surour, Adel A.; Madani, Ahmed A.] Cairo Univ, Fac Sci, Dept Geol, Giza 12613, Egypt; [Arai, Shoji] Kanazawa Univ, Dept Earth Sci, Kanazawa, Ishikawa, Japan
推荐引用方式 GB/T 7714	Abe, Natsue,Surour, Adel A.,Madani, Ahmed A.,et al. Metasomatized peridotite xenoliths from the cretaceous rift-related Natash volcanics and their bearing on the nature of the lithospheric mantle beneath the southern part of the Eastern Desert of Egypt[J],2020,370.
APA	Abe, Natsue,Surour, Adel A.,Madani, Ahmed A.,&Arai, Shoji.(2020).Metasomatized peridotite xenoliths from the cretaceous rift-related Natash volcanics and their bearing on the nature of the lithospheric mantle beneath the southern part of the Eastern Desert of Egypt.LITHOS,370.
MLA	Abe, Natsue,et al."Metasomatized peridotite xenoliths from the cretaceous rift-related Natash volcanics and their bearing on the nature of the lithospheric mantle beneath the southern part of the Eastern Desert of Egypt".LITHOS 370(2020).