An international team of researchers has discovered around 100 ancient volcanoes and associated lava flows buried deep within the Cooper-Eromanga Basins in central Australia.
“The Cooper and Eromanga Basins of South Australia and Queensland are the largest onshore hydrocarbon producing region in Australia,” said Dr. Simon Holford from the University of Adelaide’s Australian School of Petroleum and colleagues from Australia and Scotland.
“But, despite about six decades of petroleum exploration and production, the Jurassic volcanic underground landscape has gone largely unnoticed.”
“The Cooper-Eromanga Basins have been substantially explored since the first gas discovery in 1963,” added Dr. Nick Schofield, from the University of Aberdeen’s Department of Geology and Petroleum Geology.
“This has led to a massive amount of available data from underneath the ground but, despite this, the volcanic rocks have never been properly understood in this region until now.”
“It changes how we understand processes that have operated in Earth’s past.”
Dr. Holford, Dr. Schofield and co-authors used advanced subsurface imaging techniques, analogous to medical CT scanning, to identify the plethora of cone-shaped volcanic craters and lava flows, and the deeper magma chambers that fed them.
Named the Warnie Volcanic Province, this volcanic region covers 7,500 km2 and was active between 180 and 160 million years ago (Jurassic period).
“The Cooper-Eromanga Basins are now a dry and barren landscape but in Jurassic times would have been a landscape of craters and fissures, spewing hot ash and lava into the air, and surrounded by networks of river channels, evolving into large lakes and coal-swamps,” the scientists said.
“While the majority of Earth’s volcanic activity occurs at the boundaries of tectonic plates, or under the Earth’s oceans, this ancient Jurassic world developed deep within the interior of the Australian continent,” Dr. Holford added.
“Its discovery raises the prospect that more undiscovered volcanic worlds reside beneath the poorly explored surface of Australia.”
The discovery is described in a paper in the journal Gondwana Research.
Jonathon P.A. Hardman et al. 2019. The Warnie volcanic province: Jurassic intraplate volcanism in Central Australia. Gondwana Research 76: 322-347; doi: 10.1016/j.gr.2019.06.012
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