The area south of Wadi Abu ghusun exposes a complete section of Oligocene and Neogene sediments. The Oligocene, lower and Middle Miocene are confined to a narrow belt in the north, wheras the Upper Miocene, Pliocene and Plio-Pleistocene sediments are exposed in the rest of the area and cover a wide and elongate depression. Eight main lithofacies associations were distinguished: Oligocene fluviatile (abu Ghusun Fm.), Lower Miocene alluvial fans and sea marginal channels (Ranga Fm.), Middle Miocene open marine carbonates (Um Mahara Fm.), Upper Miocene restricted lagoonal to sabkha evaporites (Abu Dabbab Fm.), Upper Miocene fluviatile to restricted marine (Samh Mb. of Mersa Alam Fm.), Pliocene intertidal to shallow subtidal (Gabir Mb. of Mersa Alam Fm.), Pliocene open marine carbonates (Shagra Fm.) and mixed continental and Marine Plio-Pleistocene fanglomerates (Samadi Fm.).
Three heavy mineral provinces were recognized, 1) a northern province north of Wadi Qulan with heavy mineral association pointing to a dominant, diorite and granodiorite provenance, 2) a central province between Wadi Qulan and Wadi Khasheir with a minral association pointing to a basic provenance and 3) a southern province whose mineral association point to a metavolcanics and metagabbro provenance. Siliciclastics in the southern most wadis of this last province point to a basic-metamorphic source rocks.
The lithology, textural and mineralogical characteristics of the dominantly siliciclastic formations studied point to two tropical humid climatic episodes that prevailed during accumulations of the top part of the Oligocene Abu Ghusun Fm., as wel as the basal part of the Plio-Pleistocene Samadai Fm. Humid conditions prevailed also during deposition of the basal part of the Late Miocene Samh Member of the Mersa Alam Formation. The rest of the siliciclastic sequences studied were laid down under arid to semi arid conditions.