Gravity trends and the growth of Australia: A tentative correlation

Gravity anomalies of wavelength 20 to 100 km mainly reflect density variations in the non‐sedimentary part of the crust. Elongate highs and lows of this wavelength can be used to divide the Australian continent into areas within each of which the elongate anomalies are subparallel. The relative ages of the gravity trends in adjacent areas can be inferred: those oblique to the boundary between areas are likely to be older, and those parallel, younger than the boundary. The inferred relative ages of gravity‐trend areas found using this procedure are consistent with the ages of the first major deformation of cratons inferred from geology and isotopic dating. The Australian continent is thought to have grown by the addition of areas of crust in the order suggested by analysis of the gravity trends. In regions of sedimentary cover the positions of the boundaries of the gravity‐trend areas are at present the best estimate of the extent of the geologically defined cratons.