A field of about 100 volcanoes in Australia have been discovered.
This formerly lava-spewing Jurassic landscape was buried under hundreds of feet of rock in Australia’s Cooper and Eromanga basins, a desert region in the central part of the continent known for its rich reserves of oil and natural gas.
The newly discovered volcanoes formed between 180 million and 160 million years ago and covered an area of nearly 2,900 square miles (7,500 square kilometers).
Evidence of igneous rocks in the area was first discovered more than 30 years ago. During the decades of fossil fuel extraction that followed, experts gathered a massive amount of data from underneath the ground. But it was only recently that scientists looked at this data to find out where the rocks may have been coming from.
In the new study, scientists used subsurface imaging technology, such as seismic reflection to reveal chambers of magma that once fueled the Jurassic volcanoes; channels of ancient lava flows; and volcanic craters. The scientists have now named the site the Warnie Volcanic Province, after the nearby Warnie East 1 exploration well.
What Buried The Ancient Volcanoes?
During the Jurassic period, the volcanic network would have been highly active, with cracks and craters belching lava and ash. Today, however, those volcanoes are quiet, though southeastern Australia experienced volcanic activity as recently as 5,000 years ago.
What buried the ancient volcanoes? It wasn’t a single cataclysmic event; rather, the volcanoes were submerged slowly under layers of sediment over millions of years. In fact, all of central Australia has been slowly sinking for around 160 million years, though scientists aren’t entirely sure why.
Over time, the subsidence has allowed for the accumulation of hundreds of meters of sedimentary rocks — mostly shales and sandstones — which have buried and preserved this ancient landscape.
And there are probably more other volcanic field hiding under Australia and in other parts of the world. We have a tendency to focus on what we can see, but we need to take into account things we can’t see that are buried underneath the ground.