干旱区生态环境知识资源中心(Arid): Petrogenesis of the similar to 740 Korab Kansi mafic-ultramafic intrusion, South Eastern Desert of Egypt: Evidence of Ti-rich ferropicritic magmatism

Arid

DOI	10.1016/j.gr.2019.12.013
	Petrogenesis of the similar to 740 Korab Kansi mafic-ultramafic intrusion, South Eastern Desert of Egypt: Evidence of Ti-rich ferropicritic magmatism
	Khedr, Mohamed Zaki 1; El-Awady, Amr 2; Arai, Shoji 3; Hauzenberger, Christoph 4; Tamura, Akihiro 3; Stern, Robert J.5; Morishita, Tomoaki 3
通讯作者	Khedr, Mohamed Zaki
来源期刊	GONDWANA RESEARCH
ISSN	1342-937X
EISSN	1878-0571
出版年	2020
卷号	82 页码:48-72
英文摘要	The Neoproterozoic Korab Kansi mafic-ultramafic intrusion is one of the largest (100 km(2)) intrusions in the Southern Eastern Desert of Egypt. The intrusion consists of Fe-Ti-bearing dunite layers, amphibole peridotites, pyroxenites, troctolites, olivine gabbros, gabbronorites, pyroxene gabbros and pyroxene-homblende gabbros, and also hosts significant Fe-Ti deposits, mainly as titanomagnetite-ilmenite. These lithologies show rhythmic layers and intrusive contacts against the surrounding granites and ophiolitic-island arc assemblages. The wide ranges of olivine forsterite contents (Fo(67.9-85.7)), clinopyroxene Mg# (0.57-0.95), amphibole Mg# (0.47-0.88), and plagioclase compositions (An(85.8-40.9)) indicate the role of fractional crystallization in the evolution from ultramafic to mafic rock types. Clinopyroxene (Cpx) has high REE contents (2-30 times chondrite) with depleted LREE relative to HREE, like those crystallized from ferropicritic melts generated in an island-arc setting. Melts in equilibrium with Cpx also resemble ferropicrites crystallized from olivine-rich mantle melts. Cpx chemistry and its host rock compositions have affinities to tholeiitic and talc-alkaline magma types. Compositions of maficultramafic rocks are depleted in HFSE (e.g. Nb, Ta, Zr, Th and U) relative to LILE (e.g. Li, Rb, Ba, Pb and Sr) due to the addition of subduction-related hydrous fluids (rich in LILE) to the mantle source, suggesting an islandarc setting. Fine-grained olivine gabbros may represent quenched melts approximating the primary magma compositions because they are typically similar in assemblage and chemistry as well as in whole-rock chemistry to ferropicrites. We suggest that the Korab Kansi intrusion crystallized at temperatures ranging from similar to 700 to 1100 degrees C from ferropicritic magma derived from melting of metasomatized mantle at <5 Kbar. These hydrous ferropicritic melts were generated in the deep mantle and evolved by fractional crystallization under high fO(2) at relatively shallow depth. Fractionation formed calc-alkaline magmas during the maturation of an island arc system, reflecting the role of subduction-related fluids. The interaction of metasomatized lithosphere with upwelling asthenospheric melts produced the Fe and Ti-rich ferropicritic parental melts that are responsible for precipitating large quantities of Fe-Ti oxide layers in the Korab Kansi mafic-ultramafic intrusion. The other factors controlling these economic Fe-Ti deposits beside parental melts are high oxygen fugacity, water content and increasing degrees of mantle partial melting. The generation of Ti-rich melts and formation of Fe-Ti deposits in few layered intrusions in Egypt possibly reflect the Neoproterozoic mantle heterogeneity in the Nubian Shield. We suggest that Cryogenian-Tonian mafic intrusions in SE Egypt can be subdivided into Alaskan-type intrusions that are enriched in PGEs whereas Korab Kansi-type layered intrusions are enriched in Fe-Ti-V deposits. (C) 2020 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
英文关键词	layered intrusion gabbroic rocks ferropicritic melt Fe-Ti oxides island arc setting, Egypt
类型	Article
语种	英语
国家	Egypt ; Japan ; Austria ; USA
收录类别	SCI-E
WOS记录号	WOS:000530084800004
WOS关键词	LARGE IGNEOUS PROVINCE ; ALASKAN-TYPE COMPLEX ; ARABIAN-NUBIAN SHIELD ; NI-PGE MINERALIZATION ; OXYGEN FUGACITY ; CLINOPYROXENE COMPOSITION ; LAYERED INTRUSION ; CHEMICAL CHARACTERISTICS ; SKAERGAARD INTRUSION ; PANZHIHUA INTRUSION
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/318728
作者单位	1.Kafrelsheikh Univ, Fac Sci, Dept Geol, Kafrelsheikh 33516, Egypt; 2.Zagazig Univ, Fac Sci, Geol Dept, Zagazig 44519, Egypt; 3.Kanazawa Univ, Dept Earth Sci, Kanazawa, Ishikawa 9201192, Japan; 4.Karl Franzen Univ Graz, NAWI Graz Geoctr, Inst Earth Sci, A-28010 Graz, Austria; 5.Univ Texas Dallas, Geosci Dept, Richardson, TX 75083 USA
推荐引用方式 GB/T 7714	Khedr, Mohamed Zaki,El-Awady, Amr,Arai, Shoji,et al. Petrogenesis of the similar to 740 Korab Kansi mafic-ultramafic intrusion, South Eastern Desert of Egypt: Evidence of Ti-rich ferropicritic magmatism[J],2020,82:48-72.
APA	Khedr, Mohamed Zaki.,El-Awady, Amr.,Arai, Shoji.,Hauzenberger, Christoph.,Tamura, Akihiro.,...&Morishita, Tomoaki.(2020).Petrogenesis of the similar to 740 Korab Kansi mafic-ultramafic intrusion, South Eastern Desert of Egypt: Evidence of Ti-rich ferropicritic magmatism.GONDWANA RESEARCH,82,48-72.
MLA	Khedr, Mohamed Zaki,et al."Petrogenesis of the similar to 740 Korab Kansi mafic-ultramafic intrusion, South Eastern Desert of Egypt: Evidence of Ti-rich ferropicritic magmatism".GONDWANA RESEARCH 82(2020):48-72.