Petrology and Radioactivity of the Areas Surrounding Wadi Um Sidra and Wadi Um Asmer, North Eastern Desert, Egypt

Abstract

The areas surrounding Wadi Um Sidra and Wadi Um Asmer is located at about 50 km northwest of Hurghada City in the North Eastern Desert of Egypt between Latitudes 27° 14´ and 27º 26´ N and Longitudes 33º 8´ and 33º 22´ E. The present thesis provides the geology, petrography, geochemistry and radioactivity of the exposed Neoproterozoic basement rocks. These rocks include metavolcanics, Dokhan Volcanics, monzogranites, syenogranites and alkali feldspar granites. The main target of the present work is to shed more light on the mineralogical and geochemical characteristics of younger granites and their associated uranium mineralizations with performing intensive radiometrical survey on these granites. Geologically, the metavolcanics are exposed at G. Kherm Al Asmar and represent the oldest exposed rock type in the area. They are intruded by the syenogranites and alkali feldspar granites, which send off-shoots to these volcanics and enclose them as xenoliths along their contacts. The contacts between the metavolcanics with seyogranites and alkali feldspar granites are sharp. The metavolcanics range in composition from metabasalts to meta-andesites. Petrographically, they are commonly porphyroblastic. The metabasalts are essentially composed of plagioclases (An40-60), hornblende and pyroxene phenocrysts embedded in fine-grained groundmass of the same compositions. Opaques are the main accessory minerals while chlorite, epidote and saussurite occur as secondary minerals. The meta-andesites are composed essentially of plagioclases (An30-45) and hornblende phenocrysts embedded in