Geochemistry of Pan-African volcanic arc sequences in southeastern Sinai Peninsula and plate tectonic implications |
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| Authors: | Harald Furnes Aryeh E Shimron David Roberts |
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| Institution: | 1. Geologisk institutt, Avd.A, Allegt. 41, 5014 Bergen Norway;2. Geological Survey of Israel, Jerusalem Israel;3. Norges geologiske undersøkelse, Postboks 3006, 7001 Trondheim Norway |
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| Abstract: | Major and trace elements of lavas, dykes and plutonic rocks of the late Proterozoic orogenic sequence in SE Sinai, the Kid Group, have been analysed. The dykes and lavas of the southermost sequences, the Tarr Complex and Heib Formation, are calc-alkaline, whereas the lavas of the Malhak Formation and the Sharira Gabbro (to the north of the Heib Formation) show both calc-alkaline and tholeiitic trends. The trace element characteristics of the Tarr Complex and the Heib and Malhak Formations, despite between-sequence variations, are all comparable with ensialic island arc magmatism, whereas the Sharira Gabbro shows some MORB characteristics in addition to the island arc imprints. The Sharira Gabbro and the lavas of the Malhak Formation possibly formed in a developing back-arc basin behind a continental-marginal ensialic island arc (the Tarr Complex and Heib Formation). During the Pan-African orogeny, the constituent units of the Kid Group were mutually juxtaposed along major ductile shear zones of thrust-fault character. This plate-convergence regime involved initial magmatic arc development following northward subduction, and subsequent collision between the arc complex and the Proterozoic continental margin. |
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