Pan African magmatism in the Zabara District, Central Eastern Desert, Egypt: Geochemistry and Petrogenesis

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contributor.author El Sayed, M. M. [محمد محمد السيد] en_US
date.accessioned 2009-11-25T15:24:49Z en_US
date.available 2009-11-25T15:24:49Z en_US
date.issued 1997 en_US
identifier.citation Qatar University Science Journal, 1997, Vol. 17, No. 2, Pages 431-454. en_US
identifier.uri http://hdl.handle.net/10576/10031 en_US
description.abstract The rocks of the Zabara district include ophiolitic and non-ophiolitic sequences. The ophiolitic ones are metagabbro and metabasalt associated with metasediments, whereas the non -ophiolitic sequence includes intermediate to acidic metavolcanics and two -mica younger granites. The metasediments are felsic with Si02 ranging from 68 to 72 wt% with relatively low Cr and Ni contents (51 ppm and 16 ppm, respectively), which suggest that felsic rocks were predominated in their source area. The Zabara metasediments are characterised by slightly flat REE patterns and have geochemical features similar to those of the ocean island arc metasediments. The ophiolitic metagabbro and metabasalt are similar in their major and trace element contents and show a tholeiitic affinity. The ophiolitic sequence exhibits geochemical characteristics on N-MORB with very low levels of K20, Nb, Zr, Rb and Ba and flat REE patterns. The REE modelling reveals that the ophiolitic sequence could be derived by non-modal batch partial melting of spinel Iherzolite source followed by subsequent fractional crystallization of olivine, clinopyroxene and plagioclase. The non-ophiolitic metavolcanics cover the entire spectrum from medium-K meta-andesite to high-K metadacite with calc-alkaline affinity. The metavolcanics have slightly fractionated LREE and unfractionated, flat HREE. The non-ophiolitic metavolcanics represent cogenetic fractionated sequence. The highly evolved post-orogenic alkaline two mica granite exhibits peraluminous character and shows close similarity with the metarhyolite with repeat to major and trace elements. The granite could be modelled by about 70% fractional crystallisation of plagioclase, alkali feldpar, biotite, titanite and zircon from the dacitic magma. en_US
description.abstract تتكون منطقة زتجارا من تتابع افيوليتب وتتابع غير افيوليتي ، التتابع الافوليتي يتكون من الجابرو المتحول والبازلت المتحول والمصاحبة للرسوبيات المتصولة، اما التتابع الغير اشيوليتي فيضفيضكون من البركانيات المتحولة المتوسطة والحامضية مع الجرانيت الحديث . . ar
language.iso en en_US
publisher Qatar University en_US
subject Geology en_US
subject الجيولوجيا ar
title Pan African magmatism in the Zabara District, Central Eastern Desert, Egypt: Geochemistry and Petrogenesis en_US
title.alternative النشاط المجماتي البان افريقي في منطقة زبارا وسط الصحراء الشرقية، مصر : جيوكيمياء والاصل ar
type Article en_US
identifier.pagination 431-454 en_US
identifier.issue 2 en_US
identifier.volume 17 en_US


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