干旱区生态环境知识资源中心(Arid): Geotectonic significance of the Neoproterozoic ophiolitic metagabbros of Muiswirab area, South Eastern Desert, Egypt: constraints from their mineralogical and geochemical characteristics

Arid

DOI	10.1007/s11631-020-00404-8
	Geotectonic significance of the Neoproterozoic ophiolitic metagabbros of Muiswirab area, South Eastern Desert, Egypt: constraints from their mineralogical and geochemical characteristics
	Mogahed, Moustafa M.; Saad, Wlaa Mahmoud
通讯作者	Mogahed, MM
来源期刊	ACTA GEOCHIMICA
ISSN	2096-0956
EISSN	2365-7499
出版年	2020
卷号	39 期号:6 页码:887-910
英文摘要	Petrological and geochemical studies of Neoproterozoic metagabbros were carried out in the Muiswirab area, South Eastern Desert of Egypt. The Muiswirab area comprises of ophiolitic metagabbroic rocks (MOM), which are tectonically thrusted over a thick pile of metavolcanic rocks and intruded by syn- and post-tectonic granitoid rocks. The whole-rock geochemical variations coupled with chemical compositions of mineral constituents are used to attain the genesis and tectonic evolution of the studied metagabbros. The geothermobarometric investigation of the analyzed amphiboles from (MOM) revealed that these metagabbros underwent regional metamorphism under lower to upper greenschist facies (biotite zone) conditions (at a temperature of 450 to 500 degrees C and pressure of 1-3 kbar). Geochemically, the metagabbros (MOM) show tholeiitic affinity and exhibiting both arc- and MORB- like characters as evidenced by their clinopyroxene compositions and the Ti/V ratios (11.84-31.65), which considered as prominent features of forearc tectonic regime. The geochemical features suggest a probable fractionation of olivine +/- clinopyroxene +/- plagioclase as well as insignificant crustal contamination. The parental magma of the investigated MOM rocks seems to be developed in a sub-arc mantle wedge setting due to the enrichments of LILE (e.g., Rb, Ba, Sr, Pb) over HFSE (e.g., Ti, Nb, Y, Zr, Hf, Ta). The studied MOM rocks have lower values of Nb/U relative to MORB and OIB indicating that their geochemical variation produced due to the enrichment of a lithosphere mantle by OIB-like components. The ratios of Zn/Fet, La/Sm, Sm/Yb, Th/Yb and Nb/Yb indicate that the MOM rocks represent a fragment of oceanic crust originated at a supra-subduction zone environment and their parental magma developed by 5-30 % partial melting of a spinel lherzolite mantle rather than pyroxenite in an island arc setting and conformable with most of the Egyptian ophiolitic metagabbros.
英文关键词	Egypt Eastern Desert Muiswirab area Ophiolitic metagabbros N-MORB Arc tholeiites Forearc tectonic regime Volcanic-arc setting
类型	Article
语种	英语
收录类别	ESCI
WOS记录号	WOS:000516054100001
WOS关键词	IZU-BONIN-MARIANA ; DISTINCT MANTLE SOURCES ; ALASKAN-TYPE COMPLEX ; MIDOCEAN RIDGE ; CLINOPYROXENE COMPOSITION ; CONTINENTAL-CRUST ; CHLORITE GEOTHERMOMETRY ; TECTONIC IMPLICATIONS ; ARABIAN SHIELD ; TRACE-ELEMENTS
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/334234
作者单位	[Mogahed, Moustafa M.; Saad, Wlaa Mahmoud] Benha Univ Egypt, Fac Sci, Geol Dept, POB 13518, Banha, Egypt
推荐引用方式 GB/T 7714	Mogahed, Moustafa M.,Saad, Wlaa Mahmoud. Geotectonic significance of the Neoproterozoic ophiolitic metagabbros of Muiswirab area, South Eastern Desert, Egypt: constraints from their mineralogical and geochemical characteristics[J],2020,39(6):887-910.
APA	Mogahed, Moustafa M.,&Saad, Wlaa Mahmoud.(2020).Geotectonic significance of the Neoproterozoic ophiolitic metagabbros of Muiswirab area, South Eastern Desert, Egypt: constraints from their mineralogical and geochemical characteristics.ACTA GEOCHIMICA,39(6),887-910.
MLA	Mogahed, Moustafa M.,et al."Geotectonic significance of the Neoproterozoic ophiolitic metagabbros of Muiswirab area, South Eastern Desert, Egypt: constraints from their mineralogical and geochemical characteristics".ACTA GEOCHIMICA 39.6(2020):887-910.