Gravity data measures small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This East_Kimberley_Airborne_Gravity_2016_FVDBGL2500M_267_Geodetic.nc grid is a first vertical derivative of the Bouguer anomaly grid for the UNKNOWN survey. This UNKNOWNsurvey was acquired under the project No. UNKNOWN for the geological survey of UNKNOWN. The grid has a cell size of 0.00521 degrees (approximately 570m). A total of UNKNOWN UNKNOWN gravity stations were acquired to produce the original grid. A Fast Fourier Transform (FFT) process was applied to the original grid to calculate the first vertical derivative grid.

Gravity data measures small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This East_Kimberley_Airborne_Gravity_2016_FVDFAL2500M_Geodetic.nc grid is a first vertical derivative of the Bouguer anomaly grid for the UNKNOWN survey. This UNKNOWNsurvey was acquired under the project No. UNKNOWN for the geological survey of UNKNOWN. The grid has a cell size of 0.00521 degrees (approximately 570m). A total of UNKNOWN UNKNOWN gravity stations were acquired to produce the original grid. A Fast Fourier Transform (FFT) process was applied to the original grid to calculate the first vertical derivative grid.

The main part of this map is a Hue-Saturation-Intensity (HSI) image of De-trended Global Isostatic Residual Gravity data (DGIR) based on the B Series of the 2019 Australian National Gravity Grids. This series of grids represent the combination of 1.4 million ground gravity observations stored in the Australian National Gravity Database (ANGD) as of September 2019; 345,000 line km of Airborne Gravity and 106,000 line km of gravity gradiometry data in the National Australian Geophysical Database (NAGD), and the Global Gravity Grid developed at Scripps Institution of Oceanography, University of California at San Diego using data from the United States SIO, NOAA and NGA. The ground and airborne gravity data have been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940’s to the present day. The shading of the image is from the northwest and the colour scale is linear from -500 µm.s-2 (blue) to +500 µm.s-2 (red).

Legacy product - no abstract available

No abstract available

Legacy product - no abstract available

Legacy product - no abstract available

This map represents an interpretation of the geology, based on integration of airborne geophysical data, gravity data and previous geological mapping.

The Australian Calibration Line (ACL) , with a total gravity interval of 3 Gal, was established during 1970 between Laiagam in Papua New Guinea and Hobart in Tasmania. During 1973 the Australian Bureau of Mineral Resources and the USSR Geodesy and Cartography Survey made joint observations along the full length of the ACL. Measurements made with eight Soviet GAG-2 gravity meters established a gravity scale for Australia to an accuracy of 2.5 parts in 105. This scale and a datum of 979 671.86 mGal for Sydney A were adopted for Australia in 1973. The Soviet scale established for the ACL appears to be within 1 part in 104 of both the IGSN71 scale established for the Western Pacific Calibration Line by absolute determinations, pendulum measurements and international gravity meter comparisons, and the scale established for the Soviet Calibration Line by OVM pendulums. The Soviet scale for the ACL defines a milligal which is 1.5 parts in 104 larger than that defined by IGSN71 values for the ACL, and 5 parts in 104 larger than the 1965 Mean Australian Milligal that was used as an Australian milligal standard between 1965 and 1973. Both of these scales are partly based on Cambridge pendulum measurements made in Australia during 1950-51. These measurements are now thought to have been incorrect in scale. LaCoste, Romberg gravity meters have been used during six surveys along the whole or part of the ACL. The LaCoste observations have been reduced using the Soviet ACL scale and the new datum for Sydney A. The most probable values for airport gravity stations, calculated from the LaCoste results, have a precision of better than 0.01 mGal and are consistent to within experimental error with values calculated from the GAG-2 results. LaCoste observations reduced using the Soviet ACL scale give more accurate values for the gravity differences of the main intra-city ties and calibration ranges along the ACL.

Legacy product - no abstract available