The northeast border of the central Atlas Mountains lies at the hinge between three structural units: the High Atlas, the Middle Atlas and the inter-mountainous plateau of the High Moulouya. Situated along the northwest border of the African continental plate, the region’s sedimentological and geodynamic evolution was strongly influenced by both the Mediterranean (or Tethysian) mobile zone to the east and the Atlantic Ocean to the west. The other major factor influencing the area's evolution during the Mesozoic and Cenozoic eras was the intersection of the adjoining African and Iberian tectonic plates. Due to the dislocation and break-up of the supercontinent Pangaea and the resulting reactivation of the older Hercynian tectonic structures, a typical intracontinental rift system developed during the Upper Triassic period. From the Lower Jurassic to the Eocene, a remarkable diversity of facies zones developed in the depositional areas, ranging from deep platform environments to continental settings. The relatively rigid overlying strata were fractured and faulted during the initiation of the main compressive phase in the Upper Cretaceous period under the influence of the predetermined underlying faulting structure. Therefore, normal faults and thrust faults with a certain lateral extension were established over the resulting hydrogenetic and highly ductile Triassic sediments. Because of the complexity regarding the tectonic relations between the three structural units, there is a high level of interest in their junction zone, located in the research area. Therefore, the study area is divided into two different regions: the Ouaouizarth region in the southwest border of the contact zone of the High and Middle Atlas, and the Aghbala region to the northeast (the latter comprising the High Moulouya plateau and the convergence of the Atlas ranges). One of the main focuses of the present work is the establishment of a Geographic Information System (GIS) for the northern border of the High Atlas system. In order to insure subsequent use of the system, a high level of exchangeability has been implemented. As of now, there is no similar system for the entire Atlas mountain range, despite a clear and present need. Such an “AtlasGIS“ system would prove indispensable not only in the fields of ground water provisioning and natural hazard management, but in the implementing sustainable tourism model (in the framework of the UNESCO geopark concept) as well. With regard to contents, data resulting from new geological investigations conducted during this project was integrated with previously existing and readily available data (primarily geological maps, aerial photographs and satellite images). As a direct result of the AtlasGIS project, two new geological maps of the investigation area have been generated. The sedimentological and structural results of the present work fit well within the paleogeographical context of the bordering regions of the western Tethys. In particular, answers to the following questions have been outlined: • Timeframe and character of the differentiation of the High and Middle Atlas and the High Moulouya; • Dating of the Jurassic and Cretaceous Redbeds, formerly considered as free of fossils; • Influence of the deformation on the classification of the Jurassic and Cretaceous Redbed sediments; • Relationships between the post-Triassic sedimentary cover and the hercynian basement; • Chronological setting of the development of the deformation structures; • Sedimentary, paleogeographical and structural relation between the Middle and the High Atlas; Detailed lithological investigations of the geological history of the Atlas system have focused on the redbed sediments from the Dogger, Malm and the Lower Cretaceous. During these periods, important changes in environmental conditions have been noted and the first compressional structures had been detected. A geodynamic model consisting of five evolutionary phases has been developed. Furthermore, a change of polarity of the sedimentary accumulation area has been identified: although previously controlled only by the Tethys, during the Lower Cretaceous (Barremian) period the area also came under the influence of the Atlantic Ocean. Though the Turonian period, occurrences of both oceans are clearly visible. The Middle Atlas could be regarded as an estuary of the High Atlas, which shares similar sedimentary and structural developments. They do not, however, reflect the evolution of two separated basins, despite local compressions during the Dogger. The differentiation of the two mountain chains did not occur earlier than during the first compressive main phase at the uppermost Cretaceous, most likely during Tertiary.