Rocks from alost continentthat break up around 150 million year have been discovered deep beneath Baffin Island in northerly Canada , providing fresh penetration into the size and placement of this ancient landmass .
The remarkable discovery was made exclusively by accident when a team of scientist rummaged through a bunch of kimberlite rock samples that had been collected from the Chidliak Kimberlite Province by a diamond exploration company . Kimberlites are igneous rock and roll that formed millions of years ago at depths of century of kilometre , and which are sometimes coerce up to the surface by geological forces . They are of particular interest to diamond geographic expedition companies as they occasionally add these wanted rock with them as they rise from the deep .
publish in theJournal of Petrology , a team of researchers discover how the samples they prove displayed a mineral structure that is only regard in rocks belong to an ancient part of Earth ’s continental encrustation call theNorth Atlantic craton(NAC ) .
Cratonsare extremely stable sections of the lithosphere that are 1000000000000 of years old , and which modern continental plate formed around . While some cratons rest intact at the center of subsist continents , the NAC has long since split into fragments . Portions of this craton have been found across a vast area stretching from Scotland to eastern Canada , via southern Greenland . Until now , however , no remnants of the NAC had been chance on as far north as Baffin Island .
The discipline author were therefore exceedingly surprised to see such striking similarities between their kimberlite sample and the NAC . A particular game show was the constitution of a atomic number 12 iron silicate calledolivine , which is a distinctive feature film of the NAC that sets it apart from contiguous cratons in northern Canada .
“ The mineral composition of other lot of the North Atlantic craton is so alone there was no mistaking it , ” explained study author Maya Kopylova in astatement .
The discovery of fragments of the NAC in Baffin Island has major significance for our intellect of this ancient landmass , indicating it was some 10 pct larger than previously believed . Significantly , this is the first time that fragment of the planet ’s continental plate have been recover from such immense depth , with previous reconstructions of these plate being found on rocks that form at deepness of 10 kilometre ( 6 international nautical mile ) or less .
" With these sampling , we ’re able to restore the bod of ancient Continent based on deeper , mantle rock music , ” say Kopylova . “ We can now understand and map out not only the uppermost cheeseparing stratum of Earth that get up 1 percent of the planet ’s volume , but our cognition is literally and symbolically deep . We can put together 200 - kilometer deep fragments and counterpoint them ground on the detail of the deep mineralogy . ”
