Enhanced lithological mapping of Durba-Araba basement blocks, along the eastern margin of the Central Gulf of Suez Rift, Egypt, using Landsat-8 Data

Abstract

The eastern margin of the central Gulf of Suez rift exposes unique rotated basement blocks of Gabal Durba-Araba. According to geological maps, these blocks are composed of Dokhan volcanic, older, and younger granites cut by basaltic dikes and overlayed by a tilted sedimentary succession of Paleozoic to quaternary. Herein, we propose a workflow of stepwise preprocessing and classification procedures for Landsat-8 (OLI) data verified by control points from previous maps to update and improve lithological discrimination in converging areas that require further field mapping. The workflow applies digital image-processing techniques, including spectral signature analysis, band-ratio transformation, maximum likelihood, and Mahalanobis supervised classifications. The accuracy assessment of the lithological mapping reaches 86.6% and 75.7% for maximum likelihood and Mahalanobis classifications, respectively. By running the Tactical Hyperspectral Operations Resource (THOR) algorithm on the classified images, we could accurately map and modify the lithological boundaries for the following rock units: (1) gneiss-amphibolite-schist, tonalite, and granodiorite at Gabal Araba; (2) granitic gneiss, granodiorite, biotite-muscovite-leucogranite, and riebeckite-syenite-albitite at Gabal Abu Haswa; (3) Dokhan volcanic, granite biotite-muscovite-leucogranite, granites riebeckite-syenite-albitite, Pyroclastic breccia and lava flow, and NW tertiary dike at Gabal Abu Durba.