Latest news with #tectonics
Forbes
27-05-2025
- Science
- Forbes
Superplume Beneath Continent Is Splitting Africa Apart
Aerial view of Suguta River in the Great Rift Valley. Kenya. Sophisticated chemical analysis of volcanic gases from Kenya have provided the first evidence that a superplume lies beneath East Africa driving active tectonics and slowly separating the Somali plate and the Horn of Africa from the rest of the continent. An international team of scientists led by Professor Fin Stuart from the University of Glasgow, working in partnership with the Kenya Geothermal Development Company, has discovered surprising results in a new study of gases from the Menengai geothermal field in central Kenya. The rift valleys of East Africa are some of the largest and most spectacular topographic features on Earth. They extend for 3,500 kilometers through Ethiopia, Kenya, Uganda and Malawi, and host extensive volcanic fields. The rifts are the manifestation of the African tectonic plate being split apart driven by forces in the Earth's interior. However, scientists are uncertain whether the volcanism and rifting is due to shallow processes or whether it is driven by up-welling hot material from Earth's mantle. As countries along the rift zone are tapping into geothermal energy, scientists get access to new sampling sites. The researchers used gases collected from the Menengai geothermal field (started in 2009 and still in development) in central Kenya to reconstruct the source in Earth's mantle feeding the geothermal activity. The team notes that the gases are chemically indistinguishable from gases present in volcanic rocks from Hawaiʻi', where volcanism is fueled by a mantle plume. Together with the common chemical 'fingerprint' between different geothermal fields— the researchers compared their results with gas samples coming from the Red Sea to the north and from Malawi to the south — this discovery supports the theory that a single "superplume" is the main source. 'Our research suggests that a giant hot blob of rock from the core-mantle boundary is present beneath East Africa," summarizes Stuart. The plume not only drives the tectonic plates apart, but also pushes up the African continent preventing the rift zone to be flooded by the Red Sea (forming the geologically spectacular landscapes of the Afar Depression). Map of East Africa showing some of the historically active volcanoes (red triangles) and the Afar ... More Depression (shaded, center). Seismic surveys indicate the presence of a large anomaly beneath the southern tip of the African continent. Such "Large Low Shear Velocity Provinces" are composed of hot and weak mantle material, and the only other similar anomaly lies beneath the Pacific Plate. They may be the primary source feeding the mantle plume of Hawai'i and the plume beneath Africa, explaining the identical chemical signatures as described by the researchers. The study,"Neon Isotopes in Geothermal Gases From the Kenya Rift Reveal a Common Deep Mantle Source Beneath East Africa," was published in the journal Geophysical Research Letters. Additional material and interviews provided by the University of Glasgow.
The Independent
14-05-2025
- Science
- The Independent
Something is moving under the surface of Venus
Mysterious features on the surface of Venus might suggest that there is activity under its surface, scientists have suggested. Almost circular features on the surface might suggest that it has active tectonics, according to new research. Though the findings are new, the data used to discover them are actually more than 30 years old, originally found by Nasa 's Magellan mission. The behaviour is similar to the tectonic plates found on Earth, which are huge sections of crust that move on top of a viscous interior and are constantly changing the surface. Venus doesn't have tectonic plates, but researchers suggest that it is nonetheless being changed by molten material that is beneath the surface. To understand the deformations in the surface, researchers looked at coronae that are found on Venus. They can be anywhere from dozens to hundreds of miles across, there are hundreds of them on the planet, and they are thought to be formed when material rises from the planet's mantle and pushes against the crust above. The findings not only shed light on the nearby planet but might also tell us about the history of Earth. 'Coronae are not found on Earth today; however, they may have existed when our planet was young and before plate tectonics had been established,' said the study's lead author, Gael Cascioli, assistant research scientist at the University of Maryland, Baltimore County, and NASA's Goddard Space Flight Center in Greenbelt, Maryland. 'By combining gravity and topography data, this research has provided a new and important insight into the possible subsurface processes currently shaping the surface of Venus.' The data was gathered by the Magellan mission, which remains the best data on the gravity and topography of Venus despite having orbited the planet in the 1990s. That data includes details on the coronae, but at the time it was taken the cause of them remained mysterious. Researchers have proposed a number of explanations for them. But the new research involved creating detailed models that looked at what would happen if the coronae were formed by plumes from underneath – and then compared those simulations with the real data from the planet. They appeared to match up. Researchers found that of the 75 coronae in the study, 52 of them appeared to have floating mantle material underneath that is probably affecting the surface. Scientists hope that the Magellan data could soon be joined by Nasa's VERITAS mission, which will launch no earlier than 2031 and will provide new detail on the planet's gravity and other details. That could not only help understand those coronae but its geology more generally.
