Scientists have learned about the internal workings of volcanoes by studying the northward movement of the Australian continent over a ‘hotspot’ inside the Earth during the last 35 million years, which left behind volcanic relics across its landscape.
The researchers from University of Queensland (UQ), Australia, said these relics revealed that the inner structure of the Australian volcanoes became increasingly complex as the hotspot’s magma output decreased. Their research is published in Nature Geoscience. The hotspot was incredibly strong in its early stages, generating some of eastern Australia’s most beloved natural attractions, according to one of the researchers, Al-Tamini Tapu.
“These large volcanoes were active for up to seven million years,” Tapu said.
“The volcanoes formed as the continent moved over a stationary hotspot inside the planet, melting the land above it so magma could ooze upward.
“This left a treasure trove of volcanic landmarks in its wake, forming the longest chain of continental ‘hotspot’ volcanoes on Earth — along Australia’s eastern side,” said Tapu.
Enormous, long-lived lava outpourings in Tweed volcano, one of the ‘shield volcanoes’ and a popular tourist spot, may have weakened the hotspot, and caused the younger volcanoes to the south to become smaller and shorter-lived, the researchers said.
Associate Professor Teresa Ubide said that as the magma production waned, the volcanoes became internally more complicated, erupting lavas full of complex crystals.
“As these cooled down and became more viscous, it became more difficult to generate eruptions, which may have been more explosive.
“We found that the arrival of new, hotter, and gas-rich magma acts like a shaken bottle of fizzy drink, causing a build-up of pressure in the magma, and, eventually, an eruption,” said Ubide. Source: PTI