Mineralogical signature of Khor Um Safi stream sediments, Central Eastern Desert, Egypt

Abstract

The present work deals with the investigation of the mineralogical characteristics of stream sediments, as possible source of economic heavy minerals. Their heavy minerals content was separated and identified, and the most abundant economic heavy minerals are ilmenite, magnetite, garnet, rutile, leucoxene, zircon, monazite, and cassiterite. Besides the identified economic heavy minerals, some radioactive and REE-bearing minerals were found too including: thorite, xenotime, and chernovite. Also, fluorite, apatite and gold occur in the sediments. The studied stream sediments are characterized by moderate concentrations of major oxides and trace elements commonly associated with mafic rocks, and high concentrations of those associated with felsic rocks, suggesting that they were derived from different sources. The existence of some elements was interpreted in terms of their occurrence in the structure of the recorded accessory minerals such as Th, Zr, and Y. The low values of the Cr/V ratio of the stream sediments (Average = 0.48) indicate a negligible contribution from ultrabasic sources. The radioactivity measurements show a predominance of thorium over uranium as these sediments are most likely pronounced natural trap for the thorium minerals such as thorite and monazite. The low values of eU/eTh ratio (average = 0.17) indicate the removal of uranium due to supergene processes.