Geoscientists have launched an investigation into how East Africa will eventually separate into several large and small tectonic blocks along the diverging East African Rift System.
Geoscientists have launched an investigation into how East Africa will eventually separate into several large and small tectonic blocks along the diverging East African Rift System.
The study will focus on the region’s rich and deep intrusions of magma and also magma-poor continental rifts, known as dry rifts.
Dr D. Sarah Stamps, an associate professor in the Department of Geosciences, part of the Virginia Tech College of Science, has been awarded a $3 million National Science Foundation grant for the Dry Rifting In the Albertine-Rhino Graben (DRIFT) project.
‘You can think of the break-up of eastern Africa as the continuation of the break-up of Pangaea,’ said Stamps, leader of the Geodesy and Tectonophysics Laboratory. ‘Eastern Africa is actively breaking up, and if it continues, we’ll see new oceans forming. In the northern parts of East Africa, like in Ethiopia and the Afar region, it’s already extended to the point of forming baby oceanic areas. The spreading has already created new oceanic crust. The land is subsiding, and the first stages of new ocean basin formation is underway.’
Further south in the central East African Rift System, the break-up of the continent is less intense, she says.
Stamps is being supported by the Woods Hole Oceanographic Institute, the University of Kansas, Northwestern University, the University of California and Midwestern State University in Texas. Based in Uganda, the team is working with the Ugandan government’s Ministry of Energy and Mineral Development and with Makerere University in Uganda.
The team will focus on the North Western Branch of the East African Rift System in Uganda, where magma-poor rifting is taking place. A wide range of geophysical, geological, and geochemical observations will be collected, and numerical modelling of the region will be performed to understand how the magma-poor rifts form and evolve.
‘The team and I are very interested in understanding the physics of how a continent can break apart when there’s no surface expression of magma as volcanos,’ Stamps said.
She is seeking to find out whether in magma-rich rifts, strain is accommodated through lithospheric weakening from melt. She will also explore whether in magma-poor rifts, melt is present below the surface, weakening the lithosphere such that strain is accommodated during upper crustal extension. Finally, she will explore what happens in magma-poor rifts if there is no melt at depth and strain is accommodated along fluid-filled faults or pre-existing structures such as inherited compositional, structural, and rheological lithospheric heterogeneities.
Working with Stamps is a Ugandan PhD geoscience student Asenath Kwagalakwe, and two undergraduate students from the Virginia Tech College of Science Esha Islam and Crystal Lee.
Stamps said that she hoped that the study would point to improving estimates of carbon dioxide transfer into the atmosphere that occurs during continental rifting, advancing rifting models used for exploring natural resources, and creating insights into seismic hazards associated with active faulting.
