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    Earth-shattering Proof Of Continents On The Move
    By Administrator | February 1st 2007 01:20 AM | 5 comments | Print | E-mail | Track Comments
    Africa is being torn apart. And as Ethiopia's rift valley grows slowly wider, an international team of scientists is taking a unique opportunity to plot the progress of continents on the move.

    The 28-strong team is led by University of Leeds geophysicist Dr Tim Wright, who has secured a £2.5 million grant from the Natural Environment Research Council (NERC) to study the seismic events taking place in the remote Afar desert of Northern Ethiopia.

    It's here that two mighty shelves of continental crust, the African and Arabian plates, meet -- and are tearing the landscape apart.

    3D view of satellite radar measurements of how the ground moved in September 2005. Over about 3 weeks, the crust on either side of the rift moved apart by as much as 8 metres, with molten rock filling the crack between the plates. Satellite radar data is from the European Space Agency's Envisat satellite. (Figure was prepared by Tim Wright, University of Leeds using Google Earth)



    For most of the time, this happens at around the same speed that human fingernails grow -- about 16mm a year. But the gradual build-up of underground pressure can lead to occasional bursts of cataclysmic activity.

    The most dramatic event came in September 2005, when hundreds of deep crevices appeared within a few weeks, and parts of the ground shifted eight metres, almost overnight. More than two billion cubic metres of rising molten rock -- magma -- had seeped into a crack between the African and Arabian tectonic plates, forcing them further apart.

    And it has given Dr Wright's team a unique opportunity to witness plate tectonics -- the science of how continents are formed and move -- at first hand. "Much of the activity between the continental shelves takes place deep underwater at the mid-ocean ridges. Ethiopia is the only place on the planet where we can see a continent splitting apart on dry land."

    Dr Wright and his colleagues will use satellite radar imaging to measure how the ground deforms. "In its simplest form, you are taking two snapshots of the same place, separated by a period of time, to see how far they have moved apart."

    His team, which includes experts from Oxford, Cambridge, Bristol and Edinburgh universities, as well as international researchers from the US, New Zealand, France and Ethiopia, will also use GPS, seismometers, and other geophysical and geochemical techniques to determine the properties of rock and magma below the surface, and to monitor the crust's movement. They will use the data to create a 3D computer model of how magma moves through the Earth's crust to make and break continents.

    As the sides of the Ethiopian rift move apart, the gap between them is being plugged with molten rock, which then cools to form new land. And in around one million year's time the Red Sea could come flooding into the sinking region, re-shaping the map of Africa forever.

    Photo looking NNW from the central part of the eastern flank of the Dabbahu rift segment. Dabbahu volcano is ~30 km from this site. The steep scarps were formed by many episodes of slip along dipping fault planes; some faults show > 3 m of movement in the September-October episode (Figure 10). The faults displace basaltic lavas (dark rocks) and small pockets of windblown ash and dust (white rocks). Photo by Cindy Ebinger, Royal Holloway, University of London.


    "It's very exciting because we're witnessing the birth of a new ocean," said Dr Wright. "In geological terms, a million years is the blink of an eye. We don't precisely know what is going to happen, but we believe that it may turn parts of Northern Ethiopia and Eritrea into an island, before a much larger land mass -- the horn of Africa -- breaks off from the continent."

    Much of the team's work will be on the ground in the Afar region of Ethiopia, also known as the Danakil depression. It's a barren, inhospitable, but beautiful part of the world. "Afdera, one of the towns in the region, is the hottest continuously-occupied place on the planet," said Dr Wright. "Temperatures can approach 60 degrees centigrade during the summer months, so we tend to go in the winter when it's that bit cooler -- although it still gets to 45C."

    Photo looking N of the explosive vent that opened on September 26 after two days of nearly continuous seismic activity. To the right of the ~60 m-wide vent lies a 200 m-wide, 4 km-long zone of open fissures and normal faults that may mark the subsurface location of the dyke. The fault zone continues to the top of the photo to the right of the small rhyolite centre. Photo Elizabeth Baker, Royal Holloway, University of London.


    Scientists from the University of Addis Ababa who are working on the project will undertake collaborative research visits to the UK. The research will establish a firm link between the two universities, with Leeds supporting two Ethiopian students on a PhD programme which will include a year in the UK.

    "We will be training Ethiopian scientists in the use of satellite and radar technology -- skills they will be able to continue to use long after this programme has ended."

    Note: This article has been adapted from a news release issued by University of Leeds.

    Comments

    Hank
    I may be the only one commenting but I can't be the only one who thinks this is spectacular. The rate this is happening is like being able to move through time.

    And those pictures are downright incredible.

    se7en

    Yes, this is totally amazing, and the pictures are very good too. I'm just glad I'm not there.


    I hope to be able to watch this form over the next few centuries. I can't wait to observe the speciation that should result from separation!

    I hate to be the bearer of bad news but we know so littel about the universe. I wonder did it occur to anyone that since space itself can be moved and manipulated by forces we do not yet understand, could this rift opening be the precursor to something much worse ? Example a rift that suddenly opens 500 to 700 miles long and deep enough to release billions of tons of either molten lava in a violent outburst; or something less violent but more sinister such as a release of billions of tons of sulfurdioxide? Either of these indicents have the potential to eliminate man from the face of the earth either by poisoning the atmosphere or casuing such a reduction of sunlight that we prematurely enter another iceage. I say with respect to the experts in the fileds of geology and astronomy that more research is need not only to help prepare the human race in the event of the down side but also to discover what link if any that astronomical events can play in our own backyard. Sometimes even the most insignificant item can creat the most change.

    Garth, I am not sure what it is that you are requesting - there are an unlimited number of possibilities about which we have no data, not thought of, might happen, will only happen once in the life of the universe, etc. I have heard the chaos theory 'story' about the sneeze of a butterfly in China and a hurricane in Texas but it is only a parable. What is it you think should be done? How does taking what you are talking about into account change what science is doing now?