posted July 21, 2006 08:32 AM
Geologists watch birth of African oceanLast Updated Thu, 20 Jul 2006 17:08:04 EDT
CBC News
Two of Earth's major tectonic plates, Africa and Arabia, are slowly ripping apart to create a new ocean basin, geologists say.
An explosive vent opened on Sept. 26, 2005 in Ethiopia's Dabbahu volcano. (Courtesy Elizabeth Baker, Royal Holloway, University of London)
Researchers, who report in Thursday's issue of the journal Nature, had a rare opportunity to witness the creation of an eight-metre rift in the ground in September 2005, when they monitored an earthquake and volcanic eruption in Ethiopia.
"It’s amazing," said geologist and study co-author Cindy Ebinger of Royal Holloway, University of London.
"It's the first large event we have seen like this in a rift zone since the advent of some of the space-based techniques we're now using."
The rupture formed over three weeks in the Afar Desert at the southern end of the Red Sea, the researchers reported.
The plates have been separating for 30 million years.
It will take millions more before the rift completely fills with magma, rises and hardens to form a new strip of ocean floor separating much of Ethiopia and Eritrea from the rest of Africa, the researchers said.
So far, seismic and satellite measurements suggest the rift is filling with molten rock from volcanic chambers.
Continental rifts are known to break up into different segments but scientists didn't know how or why.
These researchers speculated that the segmentation is caused by underground magma flows rather than cracking at the surface.
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