In a study published in Gondwana Research, scientists looked at the Cooper and Eromanga Basins found in South Australia and Queensland. These regions represent the country’s biggest oil and gas producing areas, with 60 years of exploration and 34 years worth of data on the igneous rock dating to the Triassic and Jurassic periods.
“However, the areal extent and nature of these basaltic rocks were largely unclear,” the team wrote.
They analyzed the subsurface rock using advanced imaging techniques similar to the way computerized tomography (CT) scans are used in medicine. In doing so, they found volcanic craters, lava flows and magma chambers.
The Cooper and Eromanga Basins are now barren landscapes. However, during the Jurassic Period, the volcanoes would have been on the surface, with the area made up of “a series of fissures, and also small volcanoes, spewing lava and ash into the air,” study co-author Nicholas Schofield, from the U.K.’s University of Aberdeen, told Newsweek. “The volcanoes are now buried to about one mile below the surface.”
Their findings show this volcanic region—that they have named the Warnie Volcanic Province—would have covered an area spanning 2,900 square miles.
Most volcanoes are found at the boundaries of the tectonic plates, where sections of Earth’s crust slide past each other, creating friction and heat. The Warnie Volcanic Province is found in the interior of the continent Australia sits on. This raises questions about how the region developed, and potentially means far more “undiscovered volcanic worlds reside beneath the poorly explored surface of Australia”, Simon Holford, from the University of Adelaide, said in a statement.
Schofield added that the area where the volcanoes were found has a huge amount of subsurface data relating to it from oil and gas exploration. “However, many areas of the Earth’s surface on land, don’t have this kind of data available,” he said. “One doesn’t expect to see the volcanism we have discovered in the middle of a tectonic plate interior, so it may be the case that are other examples globally, but we just don’t have the data to discover them.”
