Assessment of the Origin, Formation and Uniformity of Some Soils, South of Rood El Farj - El Dabaa Road

The current study aimed at the assessment of the nature of soil origin, formation and the degree of soil profile uniformity in the area located South of Rood El Farj - El Dabaa Road, north western desert of Egypt. The Sentinel-2A satellite image (2022) and the Digital Elevation Model (DEM) were used to identify the common landforms which are surface of El Diffa plateau, foot slope of plateau, residual hills, local depression, gravelly sand plain, sand sheets and sand dunes. Fifteen soil profiles were morphologically described and sampled and the statistical size parameters and mineralogical constituents of sand fraction were determined. The results obtained indicated that the soil are moderately sorted to poorly sorted, strongly coarse to fine skewed and very platy to very lepto kourtic; indicating the predominance of transportation and deposition of the soil materials within aqueous media. Regarding the mineralogical composition of sand fraction, quertz represents ≥ 90.5% of the light minerals, followed by feldspars (plagioclase, orthoclase and microcline). In addition, muscovite and calcite minerals were detected in minute number. Concerning the heavy minerals, opaques are the major fraction constituent. In connection with the complementary non-opaque minerals, the first abundance are unstable minerals of igneous origin followed by the ultra-stable index minerals (sedimentary origin minerals). Metastable origin minerals are found in palpable portions. The depth-wise distribution of the index minerals as well as the uniformity and weathering ratios change irregularly indicating that the soils are formed of multi-origin parent materials that are still poorly developed.