Structural style and deformation mechanism of Neogene series of the Guercif basin (NE-Morocco)

In order to decipher the neotectonic evolution of the Guercif Neogene basin (South Rifean corridor, north-eastern Morocco), a multi-source and multi-scale observation analysis was carried out based on the combination of remote sensing and field in-situ structural geology. Hence, several characteristics of this basin not yet determined with conventional mapping tools are investigated here. In this context, based on data provided by satellite imagery (Thermal Emission and Reflection Radiometer = ASTER), a morpho-structural analysis and an interpretation of the geological characteristics of the basin areas were performed. Results provide the major directions of fracturing that affected the Guercif Neogene basin and put a relationship between these structures with the global basin evolution. Summary mapping data underline several remarkable tectonic elements, mainly the high density of fracturing in the south and southwest of the basin where competent rocks (carbonate formations) are dominant. The multidimensional field structural study carried out mainly in different sectors of the western part of the basin, highlights two main tectonic episodes in the Neogene and Plio-Quaternary. A Neogene extensive episode that corresponds to subsidence associated with fracturing by normal syn-sedimentary N90‒N135 trending faults, indicating an elongation oriented N20‒25. A recent compressive episode towards the Pliocene–Quaternary results in numerous folds of axes N20‒45 and by some small reverse faults controlled by a sub-horizontal compression of direction N120‒150. These hybrid tectonic structures are due to the regional European-African plates convergence and transpressive Middle-Atlas Shear Zone.