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AAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain

Petrogenesis and Tectonic Setting of Island Arc-Metavolcanics from UM Samiuki Area, South Eastern Desert, Egypt

Mohamed M. El-Taky1

(1) Geology, Faculty of science, Qena, Egypt.

Um Samiuki area is located at South Eastern Desert of Egypt. It occupied by a Neoproterozoic metavolcanics intruded by metadolerite and latter by granitoid rocks. The metavolcanics of investigated area are underwent low-grade regional metamorphism related to green-schist facies during Pan-African Orogeny. It is low-K content and distinguished into tholeiitic and calc-alkaline affinities. They range from basalt to rhyolite in compositions. Trace elements and rare earth elements refer that Um Smiuki metavolcanics erupted in island-arc setting and display typical island-arc geochemical signatures. It characterized by LILE enrichments, low abundances of HFSE as Ti, P, Zr, Hf and Ta with pronounced Nb anomalies and depleted HREE relative to LREE, this refer to mantle derived arc magma. Also, low Ti/V and high Ti/Zr ratios, low Nb/Y and Rb/Zr ratios, in adding to lower La/Yb<5 indicate an intra-oceanic arc setting. The constant ratios of La/Yb vs La and Ta/Th vs Sio2 through magma evolution refer to fractional crystallization of the felsic rocks through an island arc association. The presence of large amounts of pyroclastic and pillow lava refer that magma erupted in submarine environment.