Application of remote sensing data integration in detecting mineralized granitic zones: A case study of the Gabal Al-Ijlah Al-Hamra, Central Eastern Desert, Egypt

Abstract

The Gabal Al-Ijlah Al-Hamra granites in the Central Eastern Desert of Egypt are rich in rare metal-bearing minerals. The enhanced Senetinal-2-Planet fused image with 3 m spatial resolution using Gram–Schmidt fused technique was successfully used in detailed discrimination of the rock units in the study area. Various enhanced remote sensing data of Sentinel-2, Landsat-9, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and fused ASTER-Sentinel-2 datasets were used in the mapping process and verified by field investigation and petrographic analysis. The hydrothermal mineralized alteration zones related to rare metal-bearing granites were identified using ASTER and Sentinel-2 fused images. According to petrographic and ASTER mineral indices, various types of alteration zones, including sericitization, chloritization, carbonatization, kaolinitization and silicification were detected. The surface structural features were well detected using Soble directional filtering of Sentinel-1 enhanced image. The major structural directions that have been detected in Al-Ijlah Al-Hamra granitic pluton are NW-SE and NE-SW. These major trends were used to detect potential pathways for migration and concentration of rare-metals. The hyperspectral TerraSpec Halo mineral identifier (ASD) as well as petrographical investigation successfully identified the rock-forming minerals (i.e. quartz, K-feldspar, plagioclase, biotites, muscovite, chlorite, kaolinite, sericite) of syenogranites and alkali feldspar granites in the Gabal Al-Ijlah Al-Hamra area. Rare metal-bearing minerals including zircon, rutile, allanite, parisite and xenotime were identified using Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-Ray Spectroscopy (EDS). The results of remote sensing data, field observations and petrographic investigation are successfully used in exploration for rare metal-bearing minerals in the Central Eastern Desert of Egypt and similar areas worldwide.