Researchers have discovered why some parts of the Earth’s crust remain strong while others give way, overturning long-held assumptions about how continents break apart.
Published in Nature, the study examines a section of the East African Rift, one of the few places on Earth where the process of continental breakup can still be observed today.
The researchers focused on the Turkana Depression between Kenya and Ethiopia to understand why certain regions resist deformation or breaking up.
The team found that an area of the African tectonic plate that had once been stretched and thinned was now resisting deformation—the opposite of what scientists expected.
The results show that a heating event 80 million years ago had dehydrated the plate, removing water and carbon dioxide from deep layers and leaving behind a stronger, more rigid plate.
“The team brought a wide range of skills and data sets to visualize the plate structure and its properties, and our modeling systematically eliminated the possible factors controlling where plate rifting initiates,” says Cynthia Ebinger, a Tulane University professor in the earth and environmental sciences department in the School of Science and Engineering.
Tulane scientists led the earthquake and GPS monitoring that helped reveal these hidden processes. Using networks of instruments to measure both steady plate motion and rapid shifts from earthquakes, the team created three-dimensional maps showing how deformation and volcanism circumvent the previously thinned zones, leaving the thin zone barely deforming at all.
“Our collaborative research shows that volcanism and plate stretching that form deep basins avoid the thin and dry parts of the continental plates,” says Martin Musila, whose PhD research at Tulane explored the tectonic conundrum that was resolved in the paper.
“In this area, water and CO2 in the deep layers of the plate were extracted by volcanism 80 million years ago, and dehydration makes the plate stronger and seismic velocities faster.”
The findings help explain how failed rifts—ancient attempts by continents to split—can actually make tectonic plates stronger and more resistant to future breakup.
The research not only deepens understanding of earthquake and volcanic hazards but also informs models used to locate mineral and energy resources in ancient rift zones such as the Gulf Coast.
Additional researchers from the University of Montana, Imperial College London, Addis Ababa University in Ethiopia, and the University of Nairobi and Dedan Kimathi University in Kenya contributed to the work.
Funding for the project came from the US National Science Foundation and the UK Natural Environment Research Council, with additional support from the UK Global Challenges Research Fund and the National Commission for Science, Technology, and Innovation in Kenya.
Source: Tulane University
