Researchers have recently discovered world’s longest continental volcano track in Australia that is nearly three time the length of Yellowstone hotspot track is US.
Dubbed the Cosgrove hotspot track, the volcano track runs from the Whitsundays in North Queensland to near Melbourne in central Victoria. Measuring 2,000 kilometers in length the volcano track was created over a period of 33 million years as Australia moved northwards over a hotspot in the Earth’s mantle reveal a team of researchers led by Dr Rhodri Davies from Research School of Earth Sciences.
This hotspot is the reasons behind the formation of volcanoes in the Whitsundays, the central Victoria region, and some places in New South Wales, which sits almost half the way between the other two. The surprising bit about the volcano track is that it has formed away from the boundaries of tectonic plates where most of the volcanoes are found across the globe.
Because of the location where the volcano track has been found, researchers are of the opinion that the track may have formed on top of the mantle plumes near Earth’s core-mantle boundary almost 3,000 kilometres below the surface.
Another thing that researchers say is typical of such formations is that there are parts along the track where there is no volcanic activity at all. The reason behind this is the thickness of the Australian continent which acts as a barrier for the hot rock in mantle plumes to rise close enough to the Earth’s surface and melt and form magma.
At certain places along the track, researchers found that volcanic activity was only present where Earth’s solid outer layer, called the lithosphere, had a thickness of less than 130 kilometres. The clue that there are parts of the continent that are thin enough to allow melting to begin is the formation of an unusual mineral called leucitite.
According to co-author Professor Ian Campbell from the ANU Research School of Earth Sciences leucitite is found in low-volume magmas that are rich in elements such as potassium, uranium and thorium. This direct relationship between the volume and chemical composition of magma and the thickness of the continent will enable them as well as other scientists to interpret geological records better.
Dr Nick Rawlinson, now at the University of Aberdeen’s School of Geosciences, is of the opinion that such findings will enable geologists to better reconstruct the past movements of continents from other hotspots.
The study is published in Nature.