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New Ocean being Formed in Africa
PenguinRadio writes "The San Francisco Chronicle is reporting on a 37-mile long fissure that split open in September in the Afar desert in Ethiopia that could be the start of a new ocean forming. The fissure, which grew 8 meters wide in 3 weeks following an earthquake on Sept 14, is now splitting at about 0.8 inches per year, would eventually lead to Ethiopia eastern portions becoming an island in a million years or so. The findings were presented at the American Geophysical Union meeting taking place in San Francisco this week. The BBC reports that formation of a ocean basin is the first step toward developing an ocean, but that it will be millions of years before that could occur."
It's easier to form a new ocean than it is to ask the company for a raise.
fast as fast can be. you'll never catch me.
Shall I tell my kids to bookmark this article then? Just in case they forget when it all started?
Hey I have some great Ocean View Property in the middle of Africa. Email me if you're interested.
From Understanding Plate Motions
The Afar region has been stretching apart, in the process of forming a new ocean, for the last 10 or 20 million years. Stretching rates in various parts of the rift vary from 6 to 12mm per year. Parts of the Afar region are already >100m below sea level and filled with salt deposits, and the area is faulted extensively, with many tilted blocks of older material and extensive volcanoes (e.g., Erte Ale) related to the stretching (imagine the effect if you stretched a piece of candy with a brittle crust). So, the headline isn't really news at all.
The new part is the establishment and growth of such an obvious fissure where one did not exist before. The new one is fascinating, but only the latest example of a process that has been ongoing for a long time, and which will probably continue for millions of years more before the ocean eventually invades.
The Afar area is a triple junction where upwelling magma is driving 3 continental crust apart - the Arabian plate, West Africa and East Africa. The plates crack in 120 deg pieces because the configuration relieves plate extensional stress with minimal displacement. What typically happens when the basin expands is that one of arms is abandoned, again for thermodynamic reasons. Spreading along a single great circle requires less membrane deformation of the outer crust than spreading along 3. The principle of least action at work. In this case the active arms of the triple junction are the Red Sea and the East Indian ocean which are sites of rapid spreading of oceanic crust. Th East Africa Rift is clearly spread more slowly than the active arms and will fail. The North Sea, Mississipi delta, Camaroon rift, Connecticut Valley, etc are examples of rift valleys and failed arm abandonment during the opening of ocean basins. Sure, volcanism and rifting can still occur in the failed arm. The extensional faults that define these areas assures this. We see this in Afar, and deeper in the African rift. Camaroon is another example. The triple function there opened 120 Mya and it is still active. But is will never form a wide ocean basin. Afar tectonics are still a very interesting phenomen.
an ill wind that blows no good