Petrology, Geochemistry and Petrogenetic Aspects of Ediacaran Dokhan Volcanics at Wadi Zareib, Central Eastern Desert, Egypt

The present study embodies the results of field work and laboratory investigations and attempts to present the geology, petrography, geochemistry and petrogenesis of the Ediacaran Dokhan Volcanics at Wadi Zareib, Central Eastern Desert, Egypt. The investigated area is located along the Red Sea Coast and most common rock types among the Dokhan Volcanics are rhyolites and trachyandesites are commonly interbedded with lava flows successions. Microphenocrysts of quartz, alkali feldspars and plagioclase set in a fine-grained groundmass of microcrystalline to felsitic aggregates of quartz and plagioclase together with chlorite, epidote, sericite and hematite. Major element oxides and trace element data suggest that the trachyandesites are genetically related through crystal fractionation. The trace elements Y, Pb, Cu, Zr and Ga show negative anomalies (enriched) relative to Sr and Ba element. Wadi Zareib Dokhan Volcanics were originated from typical calc-alkaline reflecting the magmatic differentiation of metaluminous to peraluminous magma type. The geochemical trends of major oxides and trace elements of the studied volcanic rock varieties may suggest their co- magmatic nature. The Wadi Zareib Dokhan Volcanics display geochemical characteristics of both orogenic arc-type and anorogenic within-plate environments, suggesting eruption in a transitional "post-collisional tectonic setting. These rocks were derived from a single magma and suffered subsequence fractional crystallization.