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An undersea plateau in the Pacific Ocean that is bigger than Idaho first started organise with volcanic eruptions during theCretaceous period(145 to 66 million days ago ) , and it is still growing today .
In fact , the Melanesian Border Plateau , located east of the Solomon Islands , form through four separate pulse of volcanism , all with dissimilar theme causal agent , according to raw research bring out Jan. 15 in the journalEarth and Planetary Science Letters .
The Melanesian Border Plateau is located east of the Solomon Islands and covers an area bigger than Idaho.
This timeline is of import , because gargantuan volcanic feature under the ocean are often poorly understood , said bailiwick leaderKevin Konrad , a geoscientist at the University of Nevada , Las Vegas . In some cases , they organise in a single outpouring of magma , in which pillowcase they ’re bed as with child pyrogenous responsibility . These vast , long - lasting volcanic effect are so dramatic that they often shift the climate and have been associated with deal experimental extinction .
But in other cases , sport that depend identical to large fiery responsibility are really built over recollective periods , with multiple volcanic result piling up rock like a level bar . With limited sway samples , it can be tough to tell the conflict .
" There are some feature in the Pacific watershed where [ scientists ] have only a single sampling , and it looks like a very large monumental unmarried event , " Konrad severalise Live Science . " Sometimes when we sample these features in detail , we realize they ’re actually built over multiple pulse over tens of millions of years and would n’t have significant environmental impact . "
A size comparison of the Melanesian Border Plateau to the Pacific NW.
Konrad and his collaborators had the opportunity to sample the Melanesian Border Plateau in contingent in 2013 , during a five - week enquiry charge . They used a large range of mountains contraption to drag rock from the slopes of the undersea mountains andvolcanoesthat make up the tableland .
By canvass the ages and chemistry of these rocks , they see that the plateau likely first go organise 120 million years ago . A portion of the tableland underlying the other rock candy , known as Robbie Ridge , likely form at this time during an enormous flowage of basaltic lava . This produce a large undersea tableland that in all likelihood did not give above ocean point .
Next , 45 million years ago , that piece of the Pacific drifted over a hotspot in the mantle . hotspot are plume of heated material that uprise from the Mickey Charles Mantle and cause volcano to form in the midst oftectonic plateful . Hawaii is an good example of an island Ernst Boris Chain formed by a hotspot .
A successful rock dredge on board the R/V Roger Revelle during an expedition.
In this face , the culprit was the Rurutu - Arago hot spot , which still subsist under Gallic Polynesia today . This formed an undersea mountain chain , called a seamount , with islands rising over the sea surface . These islands erode , but 13 million years ago , the seamount drifted over yet another hot spot , the Samoa hotspot , which today is building the Samoan Islands .
" All those same conduits that magma used to go through 45 million years ago , they ’re now preexisting weaknesses that magma can start moving through 13 million years ago , " Konrad say .
This built new islands , which again eroded below ocean level over time . Finally , in the past three million years , tectonic movements at the Tonga Trench have triggered unexampled volcanic blast at the plateau — a completely dissimilar chemical mechanism than the hotspot volcanism that had come before .
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There are many hotspots in the South Pacific , Konrad said , so it ’s likely that other seamount have been construct over time in likewise complicated ways . The non-profit-making Ocean Exploration Trust and the National Oceanographic and Atmospheric Administration are taste such seamounts in the U.S.
Konrad and colleague from the University of Maryland and California State University Long Beach will soon sample mid - peaceable mountains that might have been build by overlap hotspots . Konrad purport calling these feature " oceanic mid - plate superstructures " to specialize them from the large igneous provinces create by a undivided immense volcanic effect .
" As we sample in more particular , " Konrad enunciate , " we ’re go to recover more complexness . "
