RECONSTRUCTION THE RESIDUALS OF THE LOST DRAINAGE SYSTEMS ON THE EOCENE PLATEAU OF WESTERN DESERT OF EGYPT

The Western Desert is covering an area of about 681,000 square kilometers, more than two- thirds of the total area of Egypt. The Eocene Plateau is located in the east of Western Desert. There were multiple drainage systems that preceded the Nile during Tertiary in Western Desert, but were unrelated to it. These drainage systems are commonly called “The Nile Ancestors”, such as “Late Eocene-Oligocene Drainage System” which developed before about 32 Ma, “Gilf System” which developed before about 24 Ma, and “Qena System” which developed before about 16 Ma. These complex drainage systems were hidden by burial under sand seas and dune fields or disappeared by erosion. This research is concerned with the residuals of former drainage systems which stand as ridges on the surface of Eocene Plateau. These residuals are a result of the drainage systems that disappeared by several processes of erosion, commonly called “Inverted Wadis”.

Inverted wadis on the Eocene Plateau cover an area of about 6,400 square kilometers. These features have been obtained from Google Earth, and found in six localities on the Eocene Plateau, the obtained localities can be summarized as follows, west of Esna City, east of Kharga Depression, west of Sohag City, west of Tahta City, west of Ghard Abu Moharik, and east of Bahariya Depression. In six localities, there are about 245 inverted wadis, extend from hundreds of meters to 50 kilometers in length, range from tens of meters to 500 meters in width, and do not exceed 30 meters in height.

In conclusion, the residulas of the disappeared drainage systems have been mapped for the first time. Inverted wadis on the Eocene Plateau belong to more than one drainage system, west of Ghard Abu Moharik range, west of Sohag City range, and east of Kharga Depression range might be belong to “Late Eocene-Oligocene Drainage System”, west of Esna City range might be belong to “Qena System”, west of Tahta City range might be belong to the “The Present Nile”, and east of Bahariya Depression range might be an internal drainage system which developed during Quaternary.