Extensional Tectonics of the East African Rift System
The East African Rift System is a unique site for studying rift tectonics from their incipience phase to their transitioning into sea floor spreading centers. It is also a site of growing interest because of its hydrocarbon potential, its seismic and volcanic hazards, and possible influence of human evolution. My students, co-workers and I have been conducting multi-disciplinary research in the East African Rift System focused on understanding the crustal and upper mantle structure of the Afar Depression (the most mature segment of the East African Rift System) for over ten years now. The fascination with the Afar Depression comes from that the both the Red Sea and the Gulf of Aden spreading centers step onto land and are currently propagating with Afar in a southeast and northwest directions, respectively formic embryonic spreading centers referred to as the Red Sea and the Gulf of Aden propagators. A major finding of our study is the documentation of magnetic stripes from the Red Sea propagator within the Afar Depression similar to those found at mid ocean ridges. Also, our study found that the Afar Depression is underlain by a seismic anisotropy that can best be explained as being produced from a northeast directed mantle flow. This work has been funded by Statoil (the Norwegian Oil Company).
Morpho-tectonics of the Nile
The Nile system is one of the most prominent morphological features in Africa. Understand its evolution through time and space has interested naturalists for centuries now. Over two thousands five hundred years ago, Herodotus asked the question that remained largely unanswered up to now; How Old is the Nile? My research on the Nile, together with my students and my co-workers, represents humble attempts to unveil some of the complexities of the Nile System and the interplay between regional tectonics, local structures and climate changes that shaped its morphology since the Cenozoic era. Though this research we have found that the incision of the Blue Nile in the Ethiopian plateau has accelerated since ~6 Ma due to increased uplift, we discovered a paleo-channel of the Nile in northern Sudan north of the current channel of the Nile suggesting southward migration of the river, and we have documented that the west and northwest-flowing drainage system in southern Egypt that preceded the Nile is controlled by narrow northwest-trending graben structures. This research has been supported by the National Aeronautics and Space Agency, and National Science Foundation – Office of International Science and Engineering. It provided opportunities for 24 US students to conduct geoscientific research with their peers in Egypt and Ethiopia.
The Precambrian evolution of northern Africa and Arabia
The Precambrian evolution of the East African Orogen and the surrounding regions such as the Saharan Metacraton are of great interest to understanding Precambrian crustal growth, formation and destruction of cratonic regions, and tectonic evolution of orogenic belt throughout Earth history. For the past 25 years, I have been working in different parts of the East African Orogen and the surrounding regions to understand the Precambrian evolution of this region using multi-scale observations from the outcrop level to the lithospheric structure level. An important outcome of this research effort is the introduction of the term “Saharan Metacraton” to describe the enigmatic Precambrian region west of the Nile which is not a craton, but cannot simply explained as an orogenic belt. Subsequent seismic tomography studies suggest the region is underlain by an anomalous upper mantle structure that is rarely found anywhere else on Earth. The formation of the metacraton has been explained in terms of metacratonization process where a once a stable craton partially lost its stability but was not completely destructed.