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Over 400 million years ago , an upwelling of red-hot rock from Earth ’s mantle wrenched apart the crust in Mongolia , creating an sea that survived for 115 million years .
The geological history of this ocean could help researchers understand Wilson cycle per second , or the summons by which supercontinents founder apart and hail together . These are dull , broad - scale cognitive process that progress by less than an column inch per yr , said study co - authorDaniel Pastor - Galán , a geoscientist at the National Spanish Research Council in Madrid .
A mantle plume tore a huge ocean into what is now Northewest Mongolia 410 million years ago.
" It ’s evidence us about processes in the world that are not very well-to-do to understand and that are also not very gentle to see , " Pastor - Galán say Live Science .
Geoscientists can fairly accurately remodel the breakup of the last supercontinent , Pangea , 250 million years ago . But prior to that , it ’s difficult to model exactly how the drapery and the crust interacted .
In a unexampled field , researchers were intrigued by volcanic stone in northwest Mongolia from the Devonian period ( 419 million to 359 million years ago ) .
The ocean existed when two major continents, Gondwana and Laurasia existed on Earth.
The Devonian was the " Age of the Fishes , " when Pisces dominated the ocean and plants set out to spread on landed estate . At the meter , there were two major continent , Laurentia and Gondwana , as well as a long stint of microcontinents that would finally become what is now Asia . These microcontinents step by step bump up against each other and merged in a process called accretion .
The researchers begin doing fieldwork in northwest Mongolia where rocks from these continent - building collisions are exposed on the airfoil , in 2019 , studying the age and alchemy of the ancient rock layer . They found that between about 410 million and 415 million years ago , an ocean shout the Mongol - Okhotsk Ocean opened up in the region . The alchemy of the volcanic rocks that accompany this rift revealed the presence of a mantle plume — a stream of particularly red-hot , buoyant mantle stone .
Related : Columbia , Rodinia and Pangaea — A chronicle of Earth ’s supercontinents
" Mantle plumes are usually involved in the first stage of the Wilson cycle : breakup of continents and scuttle of ocean , such as the Atlantic Ocean , " study star authorMingshuai Zhu , a prof of geology and geophysical science at the Chinese Academy of Sciences , told Live Science .
In many display case , this chance right in the midsection of a self-colored chunk of continent , tearing it aside . In this case , though , the geology is particularly complex , because the plume was tear apart crust that had previously fall together through accretion . Weak office between the accreted microcontinents , combined with the plume , belike helped the ocean to form , Zhu enounce . The researchers published their findings May 16 in the journalGeophysical Research Letters .
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The sea closed in the same situation that it opened , which is a mutual pattern in ocean life - cycles , Pastor - Galán enounce , but researchers only looked at a snapshot of the ocean ’s opening night in this study .
" A good affair is that a hotspot is comparatively static so they keep on , for many 1000000 of years , in the same place , " Pastor - Galán said . As continent in the incrustation move over the mantle hot spot , the hotspot leave behind volcanic rock-and-roll and a tell - tale chemistry ; this helps researchers track plate movement over millenary , he sound out .
Asia is no longer accreting fresh microcontinents , Pastor - Galán said , but the formation of the Mongol - Okhotsk Ocean was probably similar to what is see today at the Red Sea , where the crust is spreading by about 0.4 inches ( 1 centimeter ) per yr . The Red Sea is part of a larger continental rift that could produce a brand - new sea in easterly Africa over X of millions of age , though geologists do n’t yet know whether other continental forces will prevent that ocean from fully first step , according toEos magazine .
Zhu and his colleagues now plan to use their data to make computer models to better trace the complicated plate tectonic theory of the ancient Devonian sea .
