Application of Remote Sensing in Lithological Mapping of Umm Tawat Precambrian Rock Assemblage, North Eastern Desert, Egypt

The Precambrian rock assemblages of Umm Tawat area in the North Eastern Desert of Egypt have a distinctive ENE-trending exposure of Hammamat sediments (HS) between the Gebel Gattar granitic pluton and the volcanoclastic succession of Gebel El Dokhan. The present work applies the Landsat-8 data and image processing techniques such as spectral signature, principal component analysis, decorrelation stretch, and band ratios to map the various Precambrian rock units and the lithofacies of the HS and their geological contacts. The recognized mappable units of this assemblage are fully identified by their spectral signature, field verification, lineament analysis, and petrographic description. The resultant high-resolution lithological map based on the maximum likelihood algorithm demonstrates ten fully discriminated mappable units of younger granitoid and HS lithofacies units besides the Dokhan volcanics and metagabro-diorite rock units. The identified five HS lithofacies units are brownish gray conglomerate and sandstone HSf1, a green conglomerate with dominant volcanic fragments HSf2, fine-grained sediments of graywacke and silty-mudstone HSf3, interbedded conglomerates and siltstone with uranium enrichments related to the intrusive contact HSf4, and thermally metamorphosed pelitic sediments HSf5. Remote sensing techniques have been applied for the first time to reveal detailed facies variation of the Hammamat sediments of Umm Tawat. Finally, the results aforementioned above are imported to the Arc GIS database to update the geologic map with precise rock unit boundaries.