Basement rocks around the eastern sector of Baranis-Aswan Road, Egypt: Remote sensing data analysis and petrology

Abstract

The basement rocks around Baranis-Aswan Road, South Eastern Desert of Egypt encompasses a variety of the oldest Pan-African rock units including medium-grade hornblende schist, a variety of gneisses and migmatite as well as medium- to low-grade metavolcanics. These were intruded by syn- to late-tectonic tonalite, granodiorite, quartz diorite as well as gabbros. The exposed basement rock units in the area were discriminated with the detailed lithological mapping using the processed data of ASTER, Landsat-8 and Sentinel-2. Spectral signatures of these rocks were achieved by ASD TerraSpec Halo mineral identifier device. Petrography and geochemistry data enabled to put constraints on their petrogenesis. Geochemically, the schist and gneisses imply K-poor mafic igneous precursors that were developed in a primitive juvenile oceanic environment. The migmatite pertains to stromatic type, whereas granitic magma (neosome) was injected in hornblende schist (paleosome) through cleavage planes. The syn-tectonic tonalite to quartz diorite are also low-K, non-mature calc-alkaline rocks and pertain to oceanic plagiogranite. They display a continuous fractionation evolution trend from quartz-diorite to tonalite and granodiorite.