Friday, July 28, 2006

Continental Rift Captured Near Red Sea

Yemen Observer -- Moses has no hand in it this time. Scientists are witnessing a recent tear in the Earth’s continental crust near the Red Sea, the largest single rip seen since satellite monitoring began. The Red Sea is seen splitting in a way that could create a new ocean basin and redraw the map of Africa and Arabia.

Satellite imagery captured the huge split that appeared last year along a fault in the Afar desert in Ethiopia, where the African and Arabian tectonic plates meet, and which found the strongest indication yet of how the plates are splitting to create a new sea.

The scientists from the University of Leeds, one of the largest universities in the UK, say millions of years from now, the pulling apart of the Arabian and Nubian tectonic plates will let waters to rush into and widen the Red Sea. The Leeds scientists have also been able to get an unprecedented picture of the workings of stretching plates, the rock crust moving across Earth’s surface at up to 12 centimeters per year. While the exact course of this continental drift is hard to predict, the movement of the fault promises eventually to widen the Red Sea between Africa and the Arabian peninsula and extend it southwards, cutting a marine inlet inland.

Tim Wright of the University of Leeds and his international team of colleagues gathered ground and space-based observations of a widening fraction in the Afar Desert of Ethiopia. Between September and October of last year, a 60-kilometer-long stretch of rock spread by as much as eight meters. Magma from adjacent volcanoes filled in the bottom part of the rift, creating new continental crust and a dyke of roughly 2.5 cubic kilometers--twice as much material as erupted from Mount St. Helens--more than two kilometers below the surface. Geologists from the UK believe that they are witnessing a tectonic process similar to the one that formed the Atlantic Ocean, as adjacent plates push apart over millions of years to change the shape of the continents.

For several million years a similar process has been slowly separating the African and Arabian plates, forming the Red Sea in the north and the Great Rift Valley in East Africa. Yemeni geologists could not be reached to comment on the phenomenon.

The scientists, led by Cindy Ebinger, of Royal Holloway, and Tim Wright, of Oxford, established that as the rift was torn it was filled by magma bubbling up from chambers lying underneath two volcanoes at its northern end. This magma will eventually harden and, when submerged, will form a new ocean floor.

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