Mineralogy and Radioactivity of Stream Sediments of Wadi Abu Marw, South Eastern Desert, Egypt

Abstract

Abu Marw area is situated in the southeastern part of the Eastern Desert, about 120 km South East of Aswan. Geologically, the area is covered by late Proterozoic igneous and metamorphic rocks. These rocks are non-conformably overlain by cretaceous Nubian sandstone. The rocks are arranged from oldest to youngest rocks as follows: metagabbros, metavolcanics, older granites and younger granites. The area is dissected by several wadies e.g. Wadi Abu Marw and dissected by several drainage lines and their tributaries. The available data propose that, the studied stream sediments are potential think for accessory minerals as well as rare metal minerals that may control the geochemical enrichment of trace elements as; Co, Cu, Zn, Zr, Rb, Y, Pb and Nb. The present work adopts the ESEM/EDX –BSE and XRD an appropriate tool for the identification of the accessory minerals. These minerals are categorized as radioactive minerals (uranothorite), radioactive-bearing minerals (monazite and zircon) and non-radioactive minerals (magnetite, ilmenite, leucoxene, titanite, jarosite, spessartine, rutile, fluorite, pyrite, apatite, stibiconite, wolframite, hübnerite, scheelite, cuprotungstite meneghinite, bayldonite, cassiterite and bismuth). The radiometric study of the stream sediments of Abu Marw area indicates that the average concentrations of U and Th are 3ppm and 11.59ppm respectively, ranging from 1 to 6ppm for U and 4 to 24ppm for Th, which reveals a significant fractionation during weathering of these sediments.