According to a report by ScienceNetwork WA, the survey was conducted in February to allow geologists to study the structure of the Australia’s crust.
Dr Ian Tyler, assistant director of geoscience mapping at the Geological Survey of Western Australia, explained that the survey differed from the more common seismic surveys used to find oil in shallow basins of up to about 6km.
“What we’ve been doing over the last 15 years or so in Australia is looking at greater depths to the full depth of the crust,” he told ScienceNetwork WA.
The survey, which used the vibroseis seismic reflection technique, completed an 860km east-west continental transect from Haig, Western Australia to Tarcoola, South Australia, covering largely under-explored areas between two of the world’s most prospective geological regions.
The survey, combined with data obtained by drilling eight stratigraphic holes, showed that relatively young Mesoproterozoic bedrock lay beneath the Nullarbor Plain. This was wedged between two much older formations, WA’s Yilgarn Craton and South Australia’s Gawler Craton – both former tectonic plates.
“First of all, you’ve got the Eucla Basin sitting on top, which is an old sea floor essentially sitting on an old basement. But the rocks underneath are like nothing we’ve probably seen in outcrops anywhere else on the Australian continent,” Tyler said.
He explained that the basement structure seemed to be a much younger piece of crust – about 1600 million to one billion years old, adding, “This may represent a history of ocean basin closure and collision during that period but this is speculation.”
Data from the survey is still being interpreted. After it has been processed, it will be released to the public.
The original ScienceNetwork WA article is available at www.sciencewa.net.au