Sedimentological characteristics of continental sabkha, south Western Desert, Egypt

Abstract

Continental sabkha is recorded in the extreme middle part of the south Western Desert of Egypt representing one of the most promising areas for sustainable development, especially for agriculture. The geomorphologic units of the area are formed under the influence of structural, lithological, and/or climatic controls. These units include pediplain, depressions, mass-wasted blocks, residual hills, drainage lines, and aeolian landforms. The effective deflation process is reinforced by the lack of protective vegetation cover and the susceptibility of weakly consolidated rocks to wind removal. Different rock units covering the area range in age from Early Cretaceous to Quaternary. Quaternary deposits include playa/sabkha deposits where the continental sabkha is divided into four zones A, B, C, and D. Underground waters coming from the north and east were progressively enriched in solute by interaction with the surrounding sedimentary and igneous rocks. Most of the evaporite minerals grow displacively as a result of evaporative pumping. Mineralogically, the continental sabkha salt complex includes gypsum, natroalunite, tamarugite, bloedite, eugsterite, nitratine, halite, and D’ansite. Some of the major and trace elements (SiO2, Al2O3, Fe2O3, MgO, CaO, Na2O, K2O, as well as Rb, Ba, Zr, Sr, Y, V, and Zn) were measured. The correlation and enrichment of these major and trace elements indicate the origin of the salt complex in the sabkha.