A study published in Geology looked at the eastern of Africa, where for the past few million years the upwelling of material from the mantle has been giving origin of a rift that starts in Syria, descends from the Red Sea and reaches Mozambique and Madagascar: it is the Rift Valley, a 6,000-kilometer-long rift destined to separate a portion of Africa from the rest of the continent.
For geologist Sarah Stamps (Virginia Tech), coordinator of the study, "the rate of opening of the rift is a few millimeters per year, so it will be millions of years before we see a new ocean between those two portions of Africa." There is one important fact highlighted by the study, however: the velocity is greater toward Somalia and Ethiopia than it is toward Mozambique, so the new seas that will split the continent's plates will first form to the north.
The speed difference is giving rise to two microplates affecting the island of Madagascar, which is "pulled" to the north by the Somali microplate and to the south by the Lwandle microplate. As a result, the central part of the large island is deforming, but, according to the researchers, the deformation is not rigid: Madagascar is not breaking up like a dry branch, but deforming like it was plasticine, and this should not lead to major seismic phenomena-at least in theory.
Conducted on the basis of satellite GPS data and using sophisticated predictive models, the study is particularly important because it goes beyond pure scientific knowledge: in fact, understanding how a plate fractures and moves takes us a big step closer to understanding of earthquakes and volcanic phenomena.
Image: The Great Rift Valley (Great Tectonic Trench) is a geological rift that stretches 6,000 km, visible here on the surface in the Republic of Kenya. Jeff and Joyellen Hazard.
Post a Comment