Paper No. 8
Presentation Time: 10:45 AM
TECTONICS-INDUCED DRAINAGE DISLOCATION IN THE EASTERN DESERT OF EGYPT
Development of paleorivers in the Egyptian deserts was driven by topographic elevation, tectonic movements and distance from the Earth's Equator. The latter controlled prevalence of wet tropical conditions over a large stretch of the North African Sahara. Under the present dryness, the Eastern Desert wadis (valleys) contribute no sediments to the Nile. However, they received runoff from the Red Sea highlands during previous rainfall events. They drained northward prior to the formation of present Nile as the Cretaceous/Tertiary limestone plateau made a barrier to the west. Later tectonic disturbances along the Red Sea highlands produced the East-West wadis such as Natash, Kharit, Shait, Matula, and Batur. The drainage dislocations are inferred from diverted valleys, rock mass movements and tectonic capture processes. Synthetic Aperture Radar (SAR) data reveal that the now arid Wadi Batur east of Idfu twon has two outlets. The first, located in the upstream, is an abandoned branch of a NW trend, of an older river trace that drained northward. It shows a segment along Wadi Matula northward was connected to the earlier Wadi Qena, and was later interrupted by Qena-Safaga Shear zone. The second outlet course is narrow, immature and extends westward to Idfu town, joining the earlier Nile channel and Wadi El-Sirag west of the present Nile River. This valley appears to have originally drained northward, before being captured, and was forced to drain westward due to tectonic events and/or river capture process, producing the present barbed drainage pattern of the Wadi Batur. This is the case of most of the Eastern Desert wadis. This supports the notion of a possible northward flow prior to the westward flow direction due to tectonic capture process.