Paleoenvironmental reconstruction of the Aptian-Albian deposits in the Western High Atlas (Morocco) by the geochemical study of carbonates and the exoscopy of quartz grains

Abstract

Cretaceous deposits in the Ait Ourir region have been the subject of numerous researches. Our study concerns particularly the Aptian-Albian deposits. The paleogeographic and especially paleoclimatic evolution of the Apto-Albian deposits is defined by scanning electron microscope study SEM of surface textures of quartz grains, and by the study of isotopic geochemistry (18O/16O and 13C/12C ratio). The exoscopy permitted to distinguish the sedimentary history of quartz (alteration, continental aquatic transport). The SEM examination of the surfaces of the quartz grains permitted to identify various figures related either to the primitive crystalline system of the quartz grains or to the corrosive actions specific to the alteration environment. The isotope geochemistry consists to study radioactive or stable isotopes of organic and/or inorganic substance in order to identify and understand the physical, biological or geochemical processes which are the origin of the observed variations.