Relationship between Karstification and Tectonism in the Upper Jurassic Evaporite Formation: A Case Study of the Lalla Fatna Escarpment Safi, Morocco

Abstract

The Upper Jurassic Evaporite Formation accumulated up to 200 m of interbedded gypsum-carbonates layers across the coastal cliffed region of Safi (Morocco) have been affected by karstification process, resulting in karst collapse and subsidence structures associated with faulting, fracturing and different types of instabilities, which are among the main causes of natural hazard risk, impacting the socio-economic and environmental issues. Surface investigation (physiognomic approach) allowed the characterization and identification of deep-seated and subjacent gypsum interstratal stages and showed that the karstic features are controlled by orientations of faults and fractures. To highlight the relationship between tectonics and karstification, in this area, fracture orientations were studied, and the result of analysis of diagrams showed that, in most cases, orientations of karst landforms are controlled by regional tectonic features.