Depositional history of the Holocene Faiyum Paleolake (Egypt) inferred from a petrographic analysis

Abstract

The Faiyum Depression basin was fed by the Nile River during high-flow seasons in the Holocene. A large freshwater lake persisted in the basin during most of the Holocene. The geological setting and geomorphological characteristics of this basin has made it a topic in North African hydrology, climate, and environment, especially in Egypt. The ancient shore sediments today are fragmentary, discontinuous, and suffer from extensive erosion but substantial records of the ancient lake remain. Continuous sediment records from drill cores provided a near complete record of the Holocene history of Faiyum Lake. The recovered sedimentary sequence of one core F3-08 consists of predominantly siliciclastic lacustrine facies divisible into six informal units. Petrographic analysis provides high resolution evidence of major hydrological changes affecting the lake system. In the early-middle Holocene this lake persisted but with a lower water level and thicker sediment layers. The middle Holocene Lake experienced repetitive variations in lake level as the amount of Nile water entering the depression fluctuated. During the late Holocene, the lake level dramatically lowered in part due to the construction of earthen dams during the late Holocene and to changes in the Nile headwaters.