In what seem like a typesetter’s case of a jigsaw mishap on a tectonic musical scale , a team of researchers led by Curtin University ( CU ) has found a piece of North America – specifically , Canada – in northerly Australia . This stand for that part of Australia was attached to and was part of North America , around 1.7 billion years ago .
While this may seem remaining , and is quite a striking discovery for geologist , it ’s not all that bizarre . Remember , on human timescales , the continents seem like unmoving colossi , but to the planet , they ’ve been moving around like flotsam on an ocean .
The domain was not what it once was , quiteliterally . Although a higher internal temperature pushed tectonic plates around slightly moreaggressivelythan is presently observe , the process of home base tectonics has remained mostly unchanged for several billion years .
Once upon a time , there was a continental multitude named Laurentia . Some of its stone are 4 billion years old , and it ’s been in a ( relatively ) single coordinated while for just over a billion years . This static , ancient opus of the crust now forms the geologic core of North America , and much of it makes up what we recognize as Canada today , but it was n’t always there – it ’s been up and down this world , joining supercontinents and breaking away from them time and time again .
Weirdly , agree to late mapping by this particular team , the North Australian Craton has also got segments of Laurentia in it too . Not very many , mind you – potentially a few segment of the spikey top of Australia , and , rather endearingly , the tilt beneath Georgetown , in Queensland , which has a population of no more than 250 people .
A careful novel dating analysis of the rocks there seem to play off them up with those found in Laurentia , date back to the Proterozoic eon , between 2.5 billion and 541 million age ago . So how on Earth did they get there ?
According to theGeologypaper , the rocks beneath Georgetown – the Georgetown Inlier – were in the beginning part of western Laurentia . In fact , for some time , everything was stuck together .
A little later than 2 billion year , the world had almost finished assembling a supercontinent by the name ofNuna(or Columbia ) . Much of the continental the great unwashed we see today was spliced together in a gigantic puzzle piece , including Laurentia and Australia .
Then , 1.7 billion years ago , the Georgetown Inlier pieces were then situate in an epicontinental rift , a sea or ocean overlying a massive continental ledge . A growing chasm begin to tear the Georgetown Inlier away from Laurentia around 1.66 billion days ago , leaving a volcanic arc in its viewing .
Around this time , Nuna itself gradually began to self - destruct , breach up , and rift apart .
By around 1.6 billion year ago , as Laurentia made its way northward , this tiny Inlier refused to dog along , and or else stay behind and collide with northerly Australia .
“ The Georgetown block crossed an sea similar to how India did before colliding with Asia , ” conduct source Adam Nordsvan , a PhD student at CU , told IFLScience . “ It ’s a terrific determination . ”
He describes the Georgetown Inlier as a “ continental decoration , ” a rather beautiful term for “ a composition of continental crust that has rifted from a craton , ” in this case Laurentia .
“ New Zealand is a innovative example of this , ” he add .
Although thisisn’t the first paperto propose that parts of Australia could in fact be fraud from Laurentia , it is the first to definitely conclude this . Now we recognise a piffling more about the narrative of a long - lost supercontinent , one that ’s flummox researchers ever since its chaotic saber saw piece were first discovered .
