New images released this week provide a fresh insight into the geology beneath Australia’s vast Nullarbor Plain, one of the world’s under-explored mineral frontiers.
The images of the earth’s crust to a depth of 60 kilometres spanning a 484-kilometre stretch follow Australia’s transcontinental rail line between Cook in South Australia to Haig in Western Australia.
The new images have identified a number of large geological structures – an important first step to understanding the opportunities for mineral exploration within this frontier setting.
The State Government’s Geological Survey of South Australia in collaboration with Geoscience Australia and the Geological Survey of Western Australia produced the images as part of a non-intrusive ground seismic survey.
The latest release is the final leg of the largest study of its kind undertaken in Australia and completes a two-year, 834 kilometre study transect from Tarcoola to Haig in Western Australia.
The collaborative work has generated two sets of seismic imagery: the first provides a snapshot of the earth’s crust to 60 km depth, while the second shows the top 15 km in greater detail.
The South Australian Government has contributed $1.75 million to the $3.15 million Eucla-Gawler seismic South Australian segment, with collaborative partners Geoscience Australia and AuScope Earth Imaging providing the remaining $1.4 million.
Dr Rian Dutch, Geological Survey of South Australia said that until now, what lies beneath the Nullarbor Plain had been one of the great unknowns.
“As the largest geological study of its kind conducted in Australia, this body of work provides the international exploration community with a new window through which to view the major features beneath the Nullarbor Plain,” Dr Dutch said.
“The new imagery and the information it provides will give explorers a much better idea where to locate geological structures as a starting point in their search to locate mineral deposits of economic value near the earth’s surface.
“The Nullarbor is a genuine, greenfield exploration area, so every little bit of information is a major value-add.
When we combine ground seismic and airborne study results with information of the crustal conductivity, we can see dynamic regions where major crustal-scale structures come near the earth’s surface.
“These areas are generally more prospective as they provide pathways for fluids and magmas from the earth’s mantle to migrate into the upper-crust, potentially carrying valuable metals within reach of the surface.”
More information and access for data downloads is available at minerals.statedevelopment.sa.gov.au/eucla_gawler_seismic_survey
Magnetotelluric model superimposed on seismic interpretation of the Coompana section of the Eucla-Gawler seismic line (13GA-EG1)