The structures control the evolution of molasse basins and alteration zones occurrences in the northwestern sector of the Central Eastern Desert of Egypt

Abstract

Integration between the analyses of both fieldwork and remote sensing dataset were employed to assess the structural evolution of molasse basins and explore gold mineral deposits in the El Qash area, Central Eastern Desert of Egypt. Sandstone, mudstones, wacke, and pebbly conglomerates make up most of the sediments in the molasse basins. The younger basins (595–575 Ma) are small, less weathered, and mostly Dokhan detritus-filled basins compared to the larger older basins (> 625–605 Ma), which have more weathered sources mainly of arc metavolcanics. The molasse basins appear to have originated in a north–south regional extensional setting, characterized by a prolonged period of left-lateral transtension combined with the formation of NNE-trending synformal folds during an ENE–WSW compression phase. Notably, en-echelon arrays of normal faults, oriented perpendicular to the boundary of the strike-slip shear zone, are a recurring feature in basins formed through transtension. Furthermore, oblique NE-SW compression played a role in generating SW-dipping thrust faults and regional folding with NW–SE orientation, along with the reactivation of transtensional normal faults in a reverse manner. Multispectral satellite imagery data and radar data are used to map the relevant lithological units, structures, and hydrothermal alteration zones. This study concludes that the regions where gold deposits may be explored in connection with prospecting alteration minerals include the area around the ophiolitic assemblages, and the granitic intrusions, in addition to the felsite and the molasse sediments contacts.