Regional geological interpretation of a digital coloured residual Bouguer gravity image of eastern Australia with a wavelength cut‐off of 250 km

Abstract

A short wavelength (<250 km) residual Bouguer gravity image of eastern Australia emphasizes anomalies and anomaly patterns related to continental crustal structure in comparison with a total‐field gravity image. Filtering removes the masking effect of long wavelength anomalies, whether they have a shallow origin (e.g. extensive platform cover) or a deep source (e.g. mantle). Short wavelength anomalies are mainly caused by density differences within the crust and give a clear indication of source shape. The filtered image is particularly useful for providing basement information for large regions concealed beneath Late Palaeozoic, Mesozoic and Cainozoic cover where subsurface information is limited. The dominant characteristic of the short wavelength residual gravity image is the linear shape of anomalies which must reflect crustal structure. Groups of anomalies with similar trends define major crustal blocks. In general there is good agreement between gravity provinces and known geological units. Individu...