Geochemical Stream Sediment Survey in the Wadi Umm Rilan Area,South Eastern Desert,Egypt:A New Occurrence for Gold Mineralization

摘要

The present paper investigates the stream sediment geochemistry,behavior of gold and associated elements,delineates Au-anomalous sites and defines related sources in the Wadi Umm Rilan area.Fifty three major and trace elements were analyzed using ICP-MS and treated applying various statistical and mapping techniques.The results showed a significant difference of mean and median Au and most chemical elements in the three portions of the area,and higher values were recorded in the western portion.Furthermore,Au-anomalous sites appeared in upper and lower parts of the Wadi Umm Rilan,along the tributaries of metavolcanic unit and near granitoid contacts.This indicates the main source of Au mineralization is related to emplacement of granitoid plutons and accompanying hydrothermal solutions.There are significant indications for the presence of more than one mineralization event forming a probable single major episode of mineralization in the area,involving Au,Pb and U mineralizations.Geology,geomorphologic aspects and weathering processes could control stream sediment geochemistry,anomalies of Au and associated elements,elemental association and their dispersion patterns.Therefore,the area is fruitful and regarded as a promising target for Au exploration,using Ag,As,Sb,Cd,Cs,and Tl as pathfinder elements.