Lava samples have revealed new truth about the geological makeup of the earth’s crust and may have implications for volcanic eruption early warning systems, a study led by the University of Queensland has found.
UQ vulcanologist Dr Teresa Ubide said it was previously understood that the cooled lava from so-called “hot spot” volcanoes was “virgin” magma from the molten mantle, tens of kilometers below. Earth’s surface.
“It’s not quite the case – we’ve been misled, geologically deceived,” said Dr Ubide.
“For decades, we’ve viewed hotspot volcanoes as messengers of the Earth’s mantle, providing us with a glimpse into what’s going on deep beneath our feet.
“But these volcanoes are extremely complex inside and filter a very different melt to the surface than we expected.
“This is due to the volcano’s complex plumbing system which forces many minerals in the magma to crystallize.”
Dr Ubide said minerals are recycled by the ascending magma, altering their overall chemistry so that it “appears” pristine, which is an important new piece of the puzzle for better understanding how volcanoes in oceanic islands work.
“We found that hot spot volcanoes filter their melts to become highly eruptable at the base of the earth’s crust, located several kilometers below the volcano,” she said.
“Close monitoring of volcanoes can indicate when magma is reaching the base of the crust, where this filtering process reaches the ‘tipping point’ that leads to the eruption.
“Our results support the idea that the detection of magma at the crust-mantle boundary could indicate an upcoming eruption.
“This new information brings us one step closer to improving monitoring of volcanic unrest, which aims to protect lives, infrastructure and crops.”
Hotspot volcanoes make up some of the most beautiful landscapes in the world, such as the Canary Islands in the Atlantic and Hawaii in the Pacific.
The international team of researchers analyzed new rock samples from the island of El Hierro, in the Canary Islands in Spain, just southwest of Morocco.
This data was combined with hundreds of published geochemical data from El Hierro, including the underwater eruption of 2011 and 2012.
The team then tested the results on data from volcanoes in oceanic island hotspots around the world, including Hawaii.
Dr Ubide said hot spot volcanoes were also found in Australia.
“People in South East Queensland are very familiar with the Glass House Mountains or the Great Tweed Shield Volcano, which includes Wollumbin (Mount Warning) in New South Wales,” she said.
“Hotspot volcanoes can appear ‘anywhere’, unlike most other volcanoes that occur due to tectonic plate crushing, such as the Ring of Fire volcanoes in Japan or Nova Scotia. Zealand, or tectonic plates that move away from each other, creating for example the Atlantic Ocean.
“The volcanoes in South East Queensland hotspots were active millions of years ago.
“They have produced huge volumes of magma and make excellent laboratories for exploring the roots of volcanism.
“There are even dormant volcanoes in South Australia, which could erupt with little warning, which would benefit from better geological markers for early detection.”