USING ASTER AND GEOCHEMICAL DATA FOR GOLD EXPLORATION, SAMUT AREA, SOUTH EASTERN DESERT, EGYPT

Abstract

This study investigates the use of ASTER and geochemical data in the exploration of new gold occurrences in altered granodiorite rocks at Samut area in the Eastern Desert of Egypt. The mapping approach developed and applied in this study integrates image (ASTER) and field data sets to produce a map showing the alteration zones within granitoid rocks in the Samut area. Due to the differences in hydrothermally mineral components as well as intensities and influences of these hydrothermal activities on the surrounding rocks, various alteration processes have occurred within the host granodiorite rock. These alteration processes include sericitization, chloritization, silicification and ferrugination, resulted from the chemical interaction between the host rock minerals and mineral bearing ascending solutions. Each of the alteration processes is characterised by significantly altered minerals, in which the sericite and altered plagioclase minerals characterise the sericitization process. The biotite, muscovite, chlorite and hornblende minerals are related to chloritization. The silicification process is manifested by the quartz veins and fractured quartz grains. As well as the iron oxide (magnetite altered to goethite) minerals are characterize the ferrugination process. The chemical analyses of the unaltered granodiorites country rocks yielded Au content between 0.01 ppm and 1.61 ppm, while in the altered granodiorite, Au content is around 0.02 to 14.79 ppm. The presence of gold in the unaltered and altered granodiorite even in a low percentage, but in huge tonnages gives an importance and makes the study area worthy of gold exploration and possible exploitation and hence international propagation. Samut district is made up of intermediate to acidic metavolcanics intruded by a hornblende granodioritic pluton and cut by acidic dykes and quartz veins and veinlets. The associated hydrothermal activity to the plutonic intrusion led to the formation of promising alteration zones for gold in the granodiorite. The clarity and studying of these alterations represent the core and target of this study.