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Giant Rift In Africa Will Create a New Ocean

Posted by kdawson on from the basin-and-range dept.

Hugh Pickens writes "Researchers at the University of Rochester believe that a 35-mile rift in the desert of Ethiopia will likely become a new ocean in a million years or so, connecting the Red Sea with the Gulf of Aden. Using newly gathered seismic data, researchers have reconstructed how the rift tore open along its entire 35-mile length in just days. Dabbahu, a volcano at the northern end of the rift, erupted first, then magma pushed up through the middle of the rift area and began 'unzipping' the rift in both directions. 'We know that seafloor ridges are created by a similar intrusion of magma into a rift, but we never knew that a huge length of the ridge could break open at once like this,' says Cindy Ebinger, professor of earth and environmental sciences at the University of Rochester. The results show that highly active volcanic boundaries along the edges of tectonic ocean plates may suddenly break apart in large sections, instead of in bits, as the leading theory had previously held. The sudden large-scale events pose a much more serious hazard to populations living near the rift than would several smaller events."

9 of 168 comments (clear)

  1. Noah's flood and a massive deluge by BadAnalogyGuy · · Score: 2, Interesting

    There is a theory that the flood story of Noah is based on the actual deluge which created the Black Sea.

    Before the Flood, this area was simply a low-lying area, but approximately 5000 years ago waters from the Mediterranean Sea spilled over the Bosporus and rapidly filled the Black Sea area within days. The massive influx of water wiped out many local civilizations and probably gave rise to the Flood legend.

    If this rift is going to become a new ocean, the water must come from somewhere. If it all comes at once, we could see a massive loss of life and property, especially as the problematic area lies in some of the poorest parts of the globe. In another 5000 years, we could be debating if the Savior Adibi Christ walked with elephants!

    1. Re:Noah's flood and a massive deluge by slim · · Score: 5, Interesting

      Except that it didn't happen in just a few days....

      There are fairly mainstream theories that as the Ice Age ended, ice deposits in the Arctic melted into enormous lakes. Really enormous lakes. All that was holding this water in was ice. When finally the ice holding all this water in melted and cracked, all that water was released in a sudden catastrophic event. Rivers to dwarf anything we have today. Sea levels globally rising by several metres, in a matter of days.

      I was always dubious about the idea that a gradual rise in sea levels would result in all those deluge myths worldwide (Atlantis, Cantre'r Gwaelod, Noah, etc.). I'm much more convinced if it can be sudden. That would certainly enter into oral history.

      Unfortunately the best source I can offer right now is the Beringia Museum in Whitehorse, British Columbia. A bit of a trek for most people. I guess if I were to Google a bit I could find something online, but hey, I ain't gonna.

    2. Re:Noah's flood and a massive deluge by alen · · Score: 2, Interesting

      there was an 1800's geologist in the US who studied strange markings on the great plains. his theory was that at the end of the last ice age the ice burst and a huge avalanche of water hit the ground going so fast that it created water tornadoes that tore up the ground. the kids cartoon Ice Age copied his theory

    3. Re:Noah's flood and a massive deluge by JerkBoB · · Score: 4, Interesting

      I believe you might be referring to the Channeled Scablands in Washington State? I remember seeing a documentary about that. Interesting stuff. The research happened a bit later than the 1800s, unless you're referring to something else. More pictures and information.

      --
      A host is a host from coast to coast...
      Unless it's down, or slow, or fails to POST!
    4. Re:Noah's flood and a massive deluge by RockDoctor · · Score: 2, Interesting

      There is a theory that the flood story of Noah is based on the actual deluge which created the Black Sea.

      You've missed out the "discredited" in "a discredited theory".

      OK, that's maybe being a bit harsh on Ryan & Pitmann, whose ideas you refer to. Their theory was reasonable, plausible, and testable. It has been tested and found to be at the least flawed, if not completely unworkable. As I recall - and I'm only working from memory - one of the predictions of the Ryan/ Pitmann theory was that there would be, amongst other things, mega-dunes and other evidence of upper-flow regime erosion and redeposition in the throat of the Bhosporous. But what has been found, by shallow seismic imaging, is evidence of multiple strong flows form the Bhosporous, at multiple times, with variable spacings. So the Ryan/ Pitmann hypothesis of one Black Sea flood is disproved by the evidence. That their broader hypothesis (that the level in the Black Sea has risen substantially in pre-to-peri-historic times) is supported, but it may well have been a case of getting a couple of metres rise every few years, with a particularly midi-flood.
      To the best of my knowledge, one of the original authors (Ryan, or Pitmann ; I don't recall which) has dropped the idea after working it for a half-decade or so, while the other is continuing to try and work variations on the idea.
      Science is like that - attractive hypotheses get slain (or at least, maimed) by ugly facts.

      If this rift is going to become a new ocean, the water must come from somewhere.

      Yes, the water must come from somewhere. But to make a volume below sea level into which sea water can flood, you'll have to move one or two blocks of crust to the sides to make that "accommodation space". That space will come by moving the other sides of the appropriate continental blocks into the oceans. Which will raise the level of the seas in those oceans (probably the global ocean system). Which will make the breach of the spill point happen all the sooner.
      Geologically, the working assumption is that the volume of water in the oceans is constant. What can change more easily is the volume of the ocean basins. The largest contribution to changing that is by varying the density of rock in the seabed, either by temperature changes (which is what is happening with the rifting) or by hydration of rocks (which takes water out of the oceans ... quid pro quo).

      If it all comes at once, we could see a massive loss of life and property,

      We'd see massive movement of people and property into the highly active volcanic region first. At which point, you tell people "if you go there, you will die. Or any descendants you have who remain there will die there. you may as well face your problems here rather than try to run away there. Besides, life is probably easier here than down in that rift. Seriously - there won't even be any soil for a half-millennium or so. Spider soup (made without any drinking water ; there isn't any) is going to be your main food."
      I'd make humanitarian aid available - a sufficient number of body bags with a nice flammable lining which will make cremation easy. One would need a timing mechanism, so that the last person to die could put on the lights.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
  2. Great Lakes are in a "Failed Rift" by piotru · · Score: 3, Interesting

    Not every rift is going to become an ocean like Atlantic. Some fail, as did the rift under the Big Lakes. Correct my rusty geology if I'm wrong.

    1. Re:Great Lakes are in a "Failed Rift" by penguinchris · · Score: 2, Interesting

      It often takes several combined factors to form features like the great lakes. The glaciers played a huge role in shaping the landscape, but that's just on top of the rifting etc. I might mention also that the rifting stuff is limited to the western great lakes (particularly Superior) - lakes Erie and Ontario were formed essentially exclusively by glacial and other erosional processes. There has been a lot written on this topic - it's pretty interesting to read through the understood history of the region, and how these ideas were formed.

      As the other guy mentioned, there are a lot of interesting geology field trip stops around the great lakes that help one to understand how this works. The University of Rochester itself is basically a field trip stop - it's built on a glacial moraine. The adjacent Mt. Hope Cemetery, which dates back to the founding of the city in the early 1800s, is extremely hilly and jam-packed full of interesting glacial features. And it's quite easy to see the difference between Erie/Ontario and Superior just by visiting both areas - and not hard to imagine that they were formed by a variety of different processes.

      Source & disclaimer: I am a geology grad student, I'm originally from Buffalo, NY - on lake Erie - and I got my B.S. in geology at the University of Rochester, actually; so I'm familiar with geology of the great lakes region (particularly New York and its adjacent lakes Erie and Ontario).

  3. Land Before Time... by Jamori · · Score: 3, Interesting

    As a child, I had nightmares about the giant rifts dramatically opening in the ground like they did in the Land Before Time movie. I had since convinced myself this was unlikely to happen, and assuaged my fears.
    Thanks a lot, "Researchers at the University of Rochester"...

  4. That's somewhat different actually by penguinchris · · Score: 2, Interesting

    The basin and range represents continental crustal extension, which is spread out across the entire region. This is more-or-less driven by pulling on either end. Actually, the driving forces are not completely understood (which is why I'm using "more-or-less" to describe these things).

    Oceanic crustal extension, on the other hand, is more-or-less being pushed apart from the center. So the rifting and so on is focused in one area - the rift zone. That's why the Mid Atlantic Ridge or the East African Rift - spreading centers - are (more or less) linear features and not spread out like the basin and range is.

    Note that while I call it "oceanic crustal extension", it is obviously not limited to oceanic crust - it is rifting the continental crust in Africa. But, this is why we say a new ocean will form here, but not in the western US. When the continental crust is pushed open enough, oceanic crust will begin to form. Oceanic crust is thin and dense, which is why it's topographically lower than continental crust, which tends to form more thickly and is less dense.

    I'm a geology grad student (and my B.S. in geology is from the University of Rochester, where this latest research is from) studying tectonics, but I'll admit freely that my explanation may be wrong as this isn't really my focus (I'm more interested in compressional, rather than extensional, tectonics). So I welcome any corrections anyone can offer.