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62 million year cycle of Undersea Extinctions

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  • 09-04-2005 8:42pm
    #1
    Capt'n Midnight
    Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,827 Mod ✭✭✭✭


    Mystery Undersea Extinction Cycle Discovered

    The Berkeley researchers are physicists, not biologists or geologists or paleontologists, but they have analyzed the most exhaustive compendium of fossil records that exists -- data that cover the first and last known appearances of no fewer than 36,380 separate marine genera, including millions of species that once thrived in the world's seas, later virtually disappeared, and in many cases returned.

    The pair looked for a pattern of asteroid and comet impacts, global climate shifts, volcanic eruptions, fluctuating sea levels, changes in the total amount of plant and animal life, and the reshuffling of the continents. None fit. ... Muller and Rohde each has his own favorite guess.

    Muller suspects there is an astrophysical driving mechanism behind the 62 million year periodicity. ...“Comets could be perturbed from the Oort cloud by the periodic passage of the solar system through molecular clouds, Galactic arms, or some other structure with strong gravitational influence,” Muller said. “But there is no evidence even suggesting that such a structure exists.”

    Rohde prefers a geophysical driver, possibly massive volcanic eruptions triggered by the rise of plumes to the earth’s surface. Plumes are upwellings of hot material from near the earth’s core that some scientists believe have the potential to reoccur on a periodic basis. ...

    ... Muller and Rohde also found a second, less pronounced diversity cycle of 140 million years. ... If it is real, the 140 million year fossil diversity cycle could be tied to a reported 140 million year cycle in Ice Ages. Said Rohde, "It is also possible that this 140 million year fossil diversity cycle is driven by passage through the arms of the Milky Way galaxy".



    http://sfgate.com/cgi-bin/article.cgi?file=/c/a/2005/03/10/MNGFIBN6PO1.DTL&type=printable
    http://news.nationalgeographic.com/news/2005/03/0309_050309_extinctions.html
    http://www.lbl.gov/Science-Articles/Archive/Phys-fossil-biodiversity.html


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    #2
    ISAW
    Banned (with Prison Access) Posts: 7,142 ✭✭✭ISAW


    Capt'n Midnight wrote:
    Mystery Undersea Extinction Cycle Discovered
    As far as I remember Muller got the idea of the periodicity from alverez who WAS a geologist. But I maight be confusing the father and son. The father was a Nuclear chemist and son a geologoist. The chemits wqas pulled in to date the geological samples of one particular event the K/T boundary mass extinction i.e. the dinosaur killer.

    But Alverez wasnt the first to posit periodicity. He got the idea from mathematicians. Two zany mathematicians Raup and Sepskowisky (excuse spelling) had decided to apply mathematics to geology.

    It led to Alverez asking Muller for a mechanism. Muller cleverly came up with the Nemsis hypothesis a dark star orbiting our solar system. Such a star has never been found.

    Anyway the whole thing is a wonderful example of interdisciplinarity. Alverex senior won the Noble prize for some sub atomic particle or something and I think his son got it for finding the half land half undersea Chiculub site for the dinosaur killer. I remember the names now Walter and Luis. And I think Nemsis the death star was Mullers paper on it.


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