South Nicholson gravity data


The first pre-competitive data collected as part of the Exploring for the Future programme is now available. Geoscience Australia conducted a gravity survey in July 2017 over the South Nicholson Basin in the Northern Territory, 350 kilometres east of Tennant Creek.

The survey delivered 2,724 new gravity stations at four kilometre spacing over an area of 43,330 square kilometres (larger than the area of Switzerland). This greenfields region has been largely under-explored by industry due to younger sediment cover over prospective rocks beneath.

As part of a comprehensive package, seismic surveys have been carried out in the same area, and the processed data is expected to be available early next year. These surveys will form a suite of new information on the geology and resource potential of this region.

The data was collected using a Scintrex CG5 gravimeter and a high precision GPS system with transport provided by a Robinson R44 helicopter. The helicopter was navigated to predetermined locations by GPS, with the observer spending a couple of minutes taking a gravity reading before heading to the next site.

Gravity data are used to build three-dimensional maps of the subsurface geology by recording small changes in gravity due to the density of the different rocks; this provides important geological information for the resources industry on the potential of the area.

The new data are available online for free via the Geophysical Archive Data Delivery System (www.geoscience.gov.au/gadds).