AURIFEROUS QUARTZ VEINS AT ROMIT AREA, SOUTH EASTERN DESERT, EGYPT: GEOLOGIC SETTING AND GEOCHEMICAL SIGNATURE

Romit area is located in the southern part of Eastern Desert and covered by late Proterozoic igneous and metamorphic rocks. Metavolcanics and tonalite-granodiorites form most of the main outcrops in the area, which is cut off by quartz veins carrying radioactive and rare earth elements, in addition to gold. Major oxides were analyzed using conventional wet chemical analysis, trace element using X-ray fluorescence (XRF), rare earth elements (REE’s) by an Inductively Coupled Plasma Emission Spectrometry (ICP-ES) and U and Th chemically by Arsenazo III. The heavy minerals were investigated by using environmental scanning electron microscope (ESEM) and identified by X-ray diffraction technique (XRD). Gold concentration was confirmed using fire assay methods (EMRA). This work aims to study the geologic, geochemical and mineralogical characteristics of auriferous uraniferous quartz veins at the Romit area. The discovery of radionuclides and gold mineralization were recorded in quartz veins for the first time. The Romit quartz veins have relatively high uranium and thorium contents. The average uranium and thorium contents are 49 ppm and 75 ppm, respectively. The quartz veins of the Romit area show enrichment in some rare metal (Zr, Y, Nb, Pb and Au). The high content in some rare metal in these quartz veins is due to the invading hydrothermal fluids in the later stages of magmatic activity. So, these hydrothermal fluids are potentially important in the dissolution, transportation and precipitation of these elements in these quartz veins. Generally, the rock is characterized by relatively high content of rare earth elements and characterized by negative Eu and Ce anomalies. The identified minerals in the studied quartz veins can be grouped into U-Th-REE-bearing minerals (kasolite, uranothorite, columbite, monazite, allanite and xenotime), base metal minerals (gold, cerussite, pyrite and arsenopyrite), Oxide minerals (chromite, goethite, rutile and pyrolusite) and silicate minerals (kaolinite and spessartine). Environmental Scan Electron Microscope (ESEM) and fire assay techniques in quartz veins with high contents reach up to more than 1 ppm.