Mineralogical evolution of certain Saharan soils of Algeria (case of Ziban soils and the Oued Righ valley)

Abstract Our study area is located in the northeastern part of the Algerian Sahara, specifically in the Ziban and Oued Righ Valley regions. These lands are poorly understood from a pedogenetic perspective. This study represents an initial approach, combining both morphological and mineralogical analyses of recent and current soil covers. The interpretation of these data provides valuable insights for selecting targeted crops based on the type and significance of the edaphic constraints. Pedological analyses of the different morphological levels previously identified, combined with the results of mineralogical and microscopic investigations using X-Ray diffraction analyses, have demonstrated the role of inheritance and the aggradation of secondary minerals. These processes are predominant, with the exception of Attapulgite a fibrous mineral detected in some soil profiles which may result from neoformation. Additionally, at all levels, lateral inputs of sulfates from the closed depressions have contributed to the neoformation of gypsum. Microscopic examination revealed that gypsum invades, disrupts, and impedes the development of some secondary minerals. This phenomenon is attributed to the crystallization pressure of gypsum. This knowledge enhances our understanding of the dynamics governing soil formation and structural stability in these regions.