Geological and Petrographical Investigation of the Neoproterozoic Basement Rocks of Wadi Arak-Wadi El Qash area, Central Eastern Desert, Egypt

Abdelhameed, Mohamed; Abudeif, Abdelbaset M.; Abd El-Wahed, Mohamed; Kassem, Osama M.K.

doi:10.21608/sjsci.2023.226128.1104

Geological and Petrographical Investigation of the Neoproterozoic Basement Rocks of Wadi Arak-Wadi El Qash area, Central Eastern Desert, Egypt

Document Type : Regular Articles

Authors

¹ Geology Department, Faculty of Science, Sohag University, Sohag 82524, Egypt

² Geology Department, Faculty of Science, Tanta University, Tanta 31527, Egypt

³ Geology Department, National Research Center, Al-Behoos Str., Dokki, Cairo 12622, Egypt

10.21608/sjsci.2023.226128.1104

Abstract

The present paper focuses primarily on the geology and petrography of the Neoproterozoic basement rocks encountered in the Wadi Arak-Wadi El Qash area which is located in the extreme western side of the Central Eastern Desert of Egypt. The Wadi Arak-Wadi El Qash area is occupied and dominated by the Hammamat molasses-type sediments which overlie unconformably upon a basement of ophiolitic, arc assemblages and Dokhan volcanic, and is intruded by felsites and late to post-tectonic granites. Geological and petrographical examination revealed that the ophiolitic rocks form a NW-SE elongate belt of imbricate thrust sheets and slices of ultrabasic and basic association including serpentinites and Muweilih metabasalts together with sheared amphibolites and actinolite chlorite schist. The Arc assemblages comprise arc metavolcanic and Muweilih metaconglomerates. The island arc metavolcanic are commonly basic to intermediate with subordinate felsic composition and comprise metabasalts, metadolerite, metabasaltic andesite, metaandesite and metadacites together with their associated metaconglomerate rocks. The Muweilih metaconglomerates are intensely deformed, and their clasts were derived from pre-Dokhan volcanic rocks. The Dokhan volcanic are unmetamorphosed and embrace an association of basic to acidic lava flows together with their corresponding bedded pyroclastics. The Hammamat molasses sediments are dominated by red Igla Formation with subordinate green Shihimiya Formation. They are unmetamorphosed and classified into oligomictic and polymictic conglomerates, lithic arenites, feldspathic greywackes, siltstones, and mudstones. Felsites are characterized by plugs and dyke-like bodies and sharply intrude the Hammamat sediments. Late to post-tectonic granites are leucocratic of roughly syenogranite composition forming NW-trending pluton and intruding both Hammamat sediments and metavolcanics.

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