Airborne Gravity 2010 - Geoscience Australia

Airborne Gravity 2010
Figure 4. Elevation model from a high resolution LiDAR survey of the ‘core’ area. Detailed ground
gravity survey points shown in white.
Gravity response
The regional gravity response of the 20 by 20 km airborne gravity (AG) test area is characterized by a
gradient that produces a change of about 200 µms -2 over 20 km. This represents the transition from
high gravity values to the southwest to lower values to the northeast (Figure 5). There are some welldefined
linear anomalies of up to 25 µms -2 amplitude and wavelengths from 250 – 1000 m within the
AG and airborne gravity gradiometer (AGG) test areas (Figure 5).
The inner AGG area is centred over the broad gravity gradient where there is a distinct gravity
anomaly at the northern termination of a linear gravity high and a coincident linear magnetic feature
(Figure 5 and Figure 6). The central gravity anomaly is coincident with a very strong magnetic anomaly
(Figure 6) and a topographic feature (Figure 7 and Figure 8). The presence of a residual anomaly in
ground gravity data following application of full terrain correction (i.e., the complete Bouguer Anomaly)
(CBA) strongly suggests that the topographic variation is not sufficient to explain the entire gravity
anomaly.
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