Pan-African magmatism in the Wadi El-Imra district, Central Eastern Desert, Egypt: geochemistry and tectonic environment

Autor:	H. Furnes, Mohamed M. El-Sayed, M. A. Hassanen, S. O. Khalil
Rok vydání:	1996
Předmět:	Precambrian Igneous rock Provenance Proterozoic Magmatism Partial melting Geochemistry Geology Diorite Petrogenesis
Zdroj:	Journal of the Geological Society. 153:705-718
ISSN:	2041-479X 0016-7649
DOI:	10.1144/gsjgs.153.5.0705
Popis:	The Late Proterozoic rocks of the Wadi El-Imra district of the Central Eastern Desert, Egypt, comprise a metagabbro-diorite complex (oldest) and Older and Younger Granitoid complexes. Trace element characteristics show that the basic and granitoid rocks are of calc-alkaline affinity, but some of the Younger Granitoids grade into alkaline granites. The o Nd values of the the basic and granitoid rocks range from +8.3 to +4.9, and Nd model ages are younger or rather similar to crystallization ages. These data suggest a predominant depleted mantle derivation, indicating formation by subduction in an oceanic setting. REE patterns of the granitoid rocks suggest different modes of petrogenesis. This, coupled with the occurrence of amphibolite xenoliths in the Older Granitoids, may indicate that some of these rocks represent partial melts from basic rocks that have been amphibolitized at deep crustal levels of the oceanic arc.
Databáze:	OpenAIRE
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