The Geological Survey of South Australia (GSSA) designed the Gawler Craton Airborne Survey (GCAS) to provide high resolution magnetic, gamma-ray and elevation data covering the northern portion of the Gawler Craton. In total, 1.66 million line km were planned over an area of 295,000 km2 , covering approximately 30% of the state of South Australia.
The survey design of 200 m spaced lines at a ground clearance of 60 m can be compared with the design of existing regional surveys which generally employed 400 m line spacing and a ground clearance of 80 m. The new survey design results in ~2 x the data coverage and ~25% closer to the ground when compared to previous standards for regional surveys in South Australia.
Due to the enormous scale of the survey, the data were acquired using four contractors who employed ten systems to fly the sixteen blocks. To standardise the data from the multitude of systems, Geoscience Australia (GA) employed a comprehensive set of technical specifications. As part of these specifications the contractors were required to fly each of the ten systems over a series of test lines termed the “Whyalla Test Lines” (Whyalla).
The final GCAS data provide truly impressive high resolution regional scale products. These will allow more detailed geological interpretation of the prospective Gawler Craton.
Survey blocks available for download include:
Tallaringa North, block 1A
Tallaringa South, block 1B
Coober Pedy West, block 8A
Billa Kalina, block 8B
Childara, block 9A
Lake Eyre, block 10
The following grids are available in this download:
• Laser-derived digital elevation model grids (m). Height relative to the Australian Height Datum.
• Radar-derived digital elevation model grids (m). Height relative to the Australian Height Datum.
• Total magnetic intensity grid (nT).
• Total magnetic intensity grid with variable reduction to the pole applied (nT).
• Total magnetic intensity grid with variable reduction to the pole and first vertical derivative applied (nT/m).
• Dose rate concentration grid (nGy/hr).
• Potassium concentration grid (%).
• Thorium concentration grid (ppm).
• Uranium concentration grid (ppm).
• NASVD processed dose rate concentration grid (nGy/hr).
• NASVD processed potassium concentration grid (%).
• NASVD processed thorium concentration grid (ppm).
• NASVD processed uranium concentration grid (ppm).
The following point located data are available in this download:
• Elevation. Height relative to the Australian Height Datum. Datum: GDA94
• Total Magnetic Intensity. Datum: GDA94
• Radiometrics. Datum: GDA94
