Geophysical evidence for the hydro-tectonic origin of the Sabkha El Sheikh Zwayed Lake and the shallow fresh water supplies, Northern Sinai, Egypt
The El Sheikh Zwayed Lake is a saline lake located in northern Sinai Peninsula. The origin of the lake as well as the shallow fresh water supplies between the lake and the Mediterranean are the subject of many geological, hydrogeological, and geophysical studies. Two main hypotheses have been suggested to explain the phenomenon of the lake (i.e. hydrogeological and/or tectonic). Using direct current resistivity (DCR) and gravity data, we investigated which of these processes explain the juxtaposition and the contradiction between the location of freshwater between the sea and a saline lake to the south which is supplied by a saline aquifer. We infer from the 1D and 2D resistivity inversions that a shallow grabenal structure exists between the lake and the coast. The gravity measurements enable a subsurface NE-SW doubly plunging anticline to be suggested (and related to Syrian arc system) to the south-west side of the lake as well as a NE-SW associated deep inferred fault-line crossing the lake. The results show that the hydrogeological regime in the study area is tectonically controlled; whereby the graben structure works as a hydrogeological barrier between the lake and the sea.