Megafloods and landscape change during OIS 3 in the Sinai Mts., Egypt

The study area is situated in Egypt at the southern part of the Sinai peninsula which is framed by the shallow Gulf of Suez (< 80 m) and the deep Gulf of Aquaba (> 1.800 m), Red Sea. The peninsula is divided into three distinct parts; the northern region consisting chiefly of sandstone, plains and hills, the central area dominated by the Tih Plateau, and the mountainous southern region with peaks up to 2.629 m (Mount Catherine). Much of the Sinai is deeply dissected by river valleys, or wadis. Within the deeply incised valleys mighty sediment fillings up to 50 m are characteristic elements of the landscape’s morphology. Reaching the mountain rim the sedimentation processes formed mighty and broad alluvial fans. They did not reach the Gulf of Suez nor influenced the morphology of the Sinai Mts. Footplain. The valley fillings are dividable in three major units. Sediment characteristics clearly indicate rapid and distinguished processes with high energy. Airborne material as desert loess and dune sands is of great importance for the sediment sources. These materials originate from the partly dry Gulf of Suez and the Footplain. The alluvial sedimentation processes started around 45 ka ending before or with the LGM. Fossilized dunes both within the Sinai Mts. and on the footplain are dated as well. All datings are OSL derived. Subsequent erosion has cut the alluvial fans and caused deep incision within the valleys mostly down to the Precambrian granite as the basement of the valleys. Hence, the morphology of the Sinai Mts. and their characteristic valleys changed again completely.