New mapping of the Afar Depression: towards the better understanding of rift dynamics in a hotspot-influenced continental rift zone

The Afar Depression forms a triple junction between three rift systems: the Red Sea Rift, the Gulf of Aden Rift and the Main Ethiopian Rift. Rifting began in the Oligocene after the eruption of the Ethiopian Flood Basalts. It represents a unique modern example of hotspot-influenced continental breakup. Its emerged position allows detailed field and remote sensing investigations. Important mapping efforts in the area during the 60s and 70s provided very valuable input for the understanding of the local geology but also for the development of global tectonic, volcanological and sedimentary concepts in continental rift settings.

This study presents the compilation of a new geological map which covers the complete Afar depression and includes its Phanerozoic sedimentary and magmatic cover. The map is based on extensive literature research, remote sensing and fieldwork. The geological history of the Afar Depression has also been reviewed. The map evidences the complexity of the rift system with the interaction of distinct tectonic plates, blocks, rift segments, sedimentary basins and volcanic areas that evolve through time and space. This integrative geological map and review is used to reassess and discuss aspects of the style, evolution, kinematics and dynamics of this rift system. Studying this unique modern example of active rifting will help in the better comprehension of rift processes and passive margin development worldwide.