World's longest volcano chain discovered in Australia
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E-mail Xinhua, September 15, 2015
Australian researchers have discovered the longest chain of volcanoes in the world which runs along the east coast of the island continent.
The extinct volcano chain stretched more than 2,000 km from south Victoria to north Queensland, according to a report in the journal, Nature, on Tuesday.
"This volcanic chain was created over the past 33 million years, as Australia moved north-northeast over a mantle plume hotspot which we believe is now located in Bass Strait," said the study's lead author Dr Rhodri Davies of the Australian National University.
"This track, which we've named the Cosgrove hotspot track (after one of the extinct Victorian volcanoes in the chain), is nearly three times as long as the famous Yellowstone hotspot tracks on the North American continent."
Hotspots, which give rise to volcanoes, are said to form above the mantle plumes, tight upwellings of hot rock 3,000 km before the surface of the earth's core-mantle boundary.
A volcanic chain occurs following persistent movement of a tectonic plate over these hotspots.
Australia has only two active volcanoes, both off the mainland, located around 4,000 km south west of Perth, on Heard Island and McDonald Islands.
The researchers tracked the path of 15 known now-extinct volcanoes and noticed a parallel pattern.
Australia has three volcanic chains which run along the eastern coast, but this new discovery is the most westerly.
"Australia is actually the fastest moving continent on Earth, moving towards Indonesia at around seven centimetres per year," Davies said.
"We showed that these volcanoes are surface manifestations of the same mantle plume."
"However, the two groups of volcanoes were geochemically very distinct from each other and were separated by a gap of 700 km, so no-one ever put these two volcanic chains together."
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