Scientists have only found a world’s longest sequence of volcanoes on a continent, stealing in plain sight.
The newly detected Australian volcano sequence isn’t a finish surprise, though: Geologists have prolonged famous of small, apart bondage of volcanic activity on a island continent. However, new investigate reveals a dim hotspot once topsy-turvy underneath regions with no signs of aspect volcanism, joining these apart strings of volcanoes into one megachain.
That 1,240-mile-long (2,000 kilometers) sequence of glow spanned many of eastern Australia, from Hillsborough in a north, where rainforest meets a Great Barrier Reef, to a island of Tasmania in a south.
“The lane is scarcely 3 times a length of a famous Yellowstone hotspot lane on a North American continent,” Rhodri Davies, an earth scientist during Australian National University, said in a statement. [See Amazing Photos of a World's Wild Volcanoes]
Scientists had prolonged famous that 4 apart marks of past volcanic activity fringed a eastern apportionment of Australia, with any display particular signs of past volcanic activity, from immeasurable lava fields to fields awash in a volcanic vegetable called leucitite that’s dim gray to black in color. Some of these regions were distant by hundreds of miles, heading geologists to consider a areas weren’t connected.
But Davies and his colleagues suspected that a Australian volcanism had a common source: a layer plume that melted a membrane as a Australian image inched northward over millions of years. (Whereas many volcanoes form during a bounds of tectonic plates, where prohibited magma seeps adult by fissures in a Earth, others form when mantle plumes, or prohibited jets of magma, during a range between a layer and Earth’s core strech a surface.)
To accelerate their hypothesis, Davis and his colleagues used a fragment of radioactive argon isotopes (versions of argon with opposite atomic weights) to guess when volcanic activity initial seemed in any of these regions. They total this information with past work display how a Australian image had changed over a millennia. From this information, they could guess where and when volcanism influenced certain regions.
The group found that a same hotspot, expected from a layer plume, was obliged for all of a volcanic activity channel eastern Australia. The new volcanic chain, that a group dubbed a Cosgrove volcanic track, was shaped between 9 million and 33 million years ago. (None of a volcanoes on Australia’s mainland have been active during a new past.)
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