The Fayum Depression

Abstract

Among other mega-depressions of the Western Desert of Egypt, the Fayum Depression is the nearest to the Nile Valley. Only a 1.5–10 km wide divide separates them and facilitates the entrance of the Nile water into the Depression. This makes Fayum unique among other mega-depressions in the Western Desert. The Depression is excavated in a wide dome where it is composed of Eocene and Oligocene strata that are capped by volcanic materials. Miocene sediments are absent, since the Fayum dome was higher than the level of the Miocene Sea. Pliocene deposits are all continental and fluvial in origin. The Pleistocene deposits are all of Nile origin as the Nile waters entered into the Depression via the Hawara Channel in Early Palaeolithic, which resulted in the development of several lakes. With the intervention of man during the Ptolemaic Period, water entering the Depression was regulated according to the needs of agriculture, resulting in the shrinkage of the lake until it stood at its present-day level (45 m b.s.l). Since then, new forms have appeared at the Depression floor. Beside the lake beaches, the inverted wadis on the Nile-Fayum divide, and the Hawara Channel, which came into being during pre-Ptolemaic times, new forms were created; such are Qarun Lake, the Fayum Delta built of the Nile Silt, and the canyon-like wadis.