Lost Continent Confirmed:

Discussion in 'Earth Science' started by paddoboy, Jan 31, 2017.

  1. paddoboy Valued Senior Member

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    Researchers confirm the existence of a 'lost continent' under Mauritius
    January 31, 2017

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    Lead author Prof. Lewis D. Ashwal studying an outcropping of trachyte rocks in Mauritius. Such samples are about 6 million years old, but surprisingly contain zircon grains as old as 3000 million years. Credit: Susan Webb/Wits University
    Scientists have confirmed the existence of a "lost continent" under the Indian Ocean island of Mauritius that was left-over by the break-up of the supercontinent, Gondwana, which started about 200 million years ago.The piece of crust, which was subsequently covered by young lava during volcanic eruptions on the island, seems to be a tiny piece of ancient continent, which broke off from the island of Madagascar, when Africa, India, Australia and Antarctica split up and formed the Indian Ocean."We are studying the break-up process of the continents, in order to understand the geological history of the planet," says Wits geologist, Professor Lewis Ashwal, lead author on the paper "Archaean zircons in Miocene oceanic hotspot rocks establish ancient continental crust beneath Mauritius", published in the prestigious journal Nature Communications.

    By studying the mineral, zircon, found in rocks spewed up by lava during volcanic eruptions, Ashwal and his colleagues Michael Wiedenbeck from the German Research Centre for Geosciences (GFZ) and Trond Torsvik from the University of Oslo, guest scientist at GFZ, have found that remnants of this mineral were far too old to belong on the island of Mauritius.

    Read more at: https://phys.org/news/2017-01-lost-continent-mauritius.html#jCp
     
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  3. paddoboy Valued Senior Member

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    http://www.nature.com/articles/ncomms14086

    Archaean zircons in Miocene oceanic hotspot rocks establish ancient continental crust beneath Mauritius:


    Abstract
    A fragment of continental crust has been postulated to underlie the young plume-related lavas of the Indian Ocean island of Mauritius based on the recovery of Proterozoic zircons from basaltic beach sands. Here we document the first U–Pb zircon ages recovered directly from 5.7 Ma Mauritian trachytic rocks. We identified concordant Archaean xenocrystic zircons ranging in age between 2.5 and 3.0 Ga within a trachyte plug that crosscuts Older Series plume-related basalts of Mauritius. Our results demonstrate the existence of ancient continental crust beneath Mauritius; based on the entire spectrum of U–Pb ages for old Mauritian zircons, we demonstrate that this ancient crust is of central-east Madagascar affinity, which is presently located ∼700 km west of Mauritius. This makes possible a detailed reconstruction of Mauritius and other Mauritian continental fragments, which once formed part of the ancient nucleus of Madagascar and southern India.

     
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  5. Fraggle Rocker Staff Member

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    This is finally getting out into the popular press. The Washington Post had a rather long article about it this morning. It explained that the reason no one had expected to find a continent down there is that the continental plate is much farther down in the sea than anyone expected--from which everyone assumed that there was no continental plate.

    The new continent was named Zealandia, and is a bit smaller than Australia.

    Africa, Antarctica, Australia, the Indian-Arabian subcontinent, Madagascar, South America and Zealandia are the remnants of the land masses that separated and slipped off of Gondwanaland.
     
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  7. exchemist Valued Senior Member

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    Is there any explanation of why this fragment of continental crust is too low to rise to sea level? Abnormally thin, perhaps? Stretched in the break-up?
     
  8. iceaura Valued Senior Member

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  9. Fraggle Rocker Staff Member

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    They just found the dadgum thing! Give the poor scientists some time to figure it out. I'm not sure that we'll ever have the technology to send someone down that far.
     
  10. exchemist Valued Senior Member

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    Well actually the link in the concurrent Zealandia thread DOES offer an explanation - and it is the one I suggested: stretched in the break-up.

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