Why the Victoria Plate in Africa rotates

June 08, 2020

The East African Rift System (EARS) is a newly forming plate tectonic boundary at which the African continent is being separated into several plates. This is not a clean break. The system includes several rift arms and one or more smaller so-called microplates. According to GPS data, the Victoria microplate is moving in a counterclockwise rotation relative to Africa in contrast to the other plates involved.

Previous hypotheses suggested that this rotation is driven by the interaction of a mantle plume - an upward flow of hot rock within the Earth's mantle - with the microplate's thick craton and the rift system. But now, researchers from the German Research Centre for Geosciences GFZ in Potsdam around Anne Glerum have found evidence that suggests that the configuration of weaker and stronger lithospheric regions predominantly controls the rotation of continental microplates and Victoria in particular. Their findings were published in the journal Nature Communications.

In the paper, the researchers argue that a particular configuration of mechanically weaker mobile belts and stronger lithospheric regions in the EARS leads to curved, overlapping rift branches that under extensional motion of the major tectonic plates induces a rotation. They used 3D numerical models on the scale of the whole EARS to compute the lithosphere and upper mantle dynamics of the last 10 million years.

"Such large models run on high performance computing clusters", says Anne Glerum, main author of the study. "We tested the predictive strength of our models by comparing their predictions of velocity with GPS-derived data, and our stress predictions with the World Stress Map, a global compilation of information on the present-day crustal stress field maintained since 2009. This showed that the best fit was obtained with a model that incorporates the first order strength distributions of the EARS' lithosphere like the one we prepared."

There are many more continental microplates and fragments on Earth that are thought to rotate or have rotated. The lithosphere-driven mechanism of microplate rotation suggested in the new paper helps interpret these observed rotations and reconstruct plate tectonic motions throughout the history of the Earth.
-end-


GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre

Related Africa Articles from Brightsurf:

Reforestation plans in Africa could go awry
An international team led by an UdeM researcher publishes the findings of a study on the biogeographical history of sub-Saharan Africa.

Pacemaker need in Africa outpacing resources
The need for pacemakers in Africa will rise as life expectancy and associated cardiovascular diseases increase; however, the pacing field, including appropriate training, facilities and devices, are not sufficient to meet future need, according to an Africa Heart Rhythm Association (AFHRA) statement published in the Journal of the American College of Cardiology.

Why the Victoria Plate in Africa rotates
The East African Rift System is a newly forming plate tectonic boundary at which the African continent is being separated into several plates.

Africa in the path of COVID-19
In a New England Journal of Medicine paper, researchers urge a coordinated global effort in the face of the COVID-19 pandemic, with countries around the world [taking] concrete steps to assist Africa in staying ahead of the curve, even as they confront their own epidemics.

Risk of coronavirus importation in Africa
Egypt, Algeria and Republic of South Africa are the African countries most at risk for coronavirus COVID-19 importation in the continent, due to high air traffic with the contaminated Chinese provinces.

The Lancet: Egypt, Algeria and South Africa estimated to be at highest risk of new coronavirus cases in Africa
Increased resources, surveillance, and capacity building should be urgently prioritised in African countries with moderate risk of importing cases of novel coronavirus disease 2019 (COVID-19), as these countries are estimated to be ill-prepared to detect cases and limit transmission.

Supermarkets and child nutrition in Africa
Hunger and undernutrition are widespread problems in Africa. At the same time, overweight, obesity, and related chronic diseases are also on the rise.

Migratory birds are worse off in West Africa
Migratory sandpipers breeding in Greenland who choose to spend the winter in West Africa instead of elsewhere along the East Atlantic coast have a lower chance of survival, are more likely to skip their first breeding season and arrive later at their breeding grounds.

What can trigger violence in postcolonial Africa?
Why do civil wars and coups d'├ętat occur more frequently in some sub-Saharan African countries than others.

New strains of hepatitis C found in Africa
The largest population study of hepatitis C in Africa has found three new strains of the virus circulating in the general population in sub-Saharan Africa.

Read More: Africa News and Africa Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.