New data on the development of the African rift valley

A group of scientists from universities and research institutions from many different countries (Ethiopia, France, Germany, Italy, New Zealand and United Kingdom) and coordinated by the Institute of Geosciences and Earth Resources has shed new light into the recent evolution of the African rift valley and placed fundamental new constraints on how major sectors of continental rift valleys propagate, interact and link. By conducting fieldwork in a remote area at the border between Ethiopia and Kenya, and integrating the results of that field campaign with laboratory analysis of volcanic rocks, analysis of the seismicity, morphology and numerical modelling, the authors have been able to reconstruct the geological history of an almost unknown sector of the African rift valley: the Ririba rift, South Ethiopia. The results show that the Ririba rift formed from the southward growth of the rift valley in Ethiopia around 3.7 million years ago but, in contrast with previous theories of rifting in the region, the new data indicate that this southward growth was short-lived and aborted around 2.5 million years ago. At this time, the Ririba rift was abandoned and deformation migrated westward into the Lake Turkana region, where the Ethiopian and Kenyan sectors of the rift valley are now directly connected. Overall, the results of this research provide important new constraints on the development of continental rift systems, such as the African rift valley. They suggest that the process of rift linkage involves phases of rift propagation and abandonment that cause geologically rapid variations in the position and characteristics of volcanic and tectonic activity. The work has been published in Nature Communications, in the frame of project funded by the National Geographic Society.

Reference: Corti G., Cioni R., Franceschini Z., Sani F., Scaillet S., Molin P., Isola I., Mazzarini F., Brune S., Keir D., Erbello A., Muluneh A., Illsley-Kemp F., Glerum A. (2019). Aborted propagation of the Ethiopian rift caused by linkage with the Kenyan rift. Nature Communications, 10, Article number: 1309 (2019), DOI: 10.1038/s41467-019-09335-2.

Paper is available here: https://www.nature.com/articles/s41467-019-09335-2.

For further information please contact Giacomo Corti, CNR-IGG (giacomo.corti(at)igg.cnr(dot)it).