Spatial and temporal variations in the distribution of eastern Australian granites and related mineral deposits

Spatial and temporal analysis of the distribution of post-orogenic granites in the Tasman Element of eastern Australia indicates that the granites and associated mineral deposits define consistent trends in space and time. Two west-younging trends are present in southeast Australia – a northern trend involving post-Benambran (435–410 Ma) granites from northeastern New South Wales to southwestern Victoria and a southern trend involving post-Bindian (410–350 Ma) granites from southeastern New South Wales to western Tasmania. Both of these trends young inboard from the an inferred west-dipping convergent margin to the east. In contrast, 320–260 Ma granites in northeastern Queensland young to the north-northeast, parallel to the inferred convergent margin at the time. Post-tectonic granite-related minerals deposits (alkalic porphyry copper, granite-related rare metal (Sn, W and Mo) in intrusion-related gold) follow the trends observed in the granites. The younging trends in southeastern Australia are interpreted to reflect inboard stepping of post-tectonic extension, progressively thinning the crust westward, causing decompression melting, granite emplacement and granite-related mineralisation. The margin-parallel younging of granite magmatism seen in northeast Queensland may related to the progression of margin-parallel extension due to along-strike changes in convergence. Data from other parts of the world indicate such processes may be present on other convergent margins. Citation: Huston, D. L., Cheng, Y., Jones, S. L., Champion, D. C., Norman, M. D., Agnew, M. W., … Creaser, R. A. (2026). Spatial and temporal variations in the distribution of eastern Australian post-orogenic granites and related mineral deposits: metallogenic and tectonic significance. Australian Journal of Earth Sciences, 73(1), 114–131. https://doi.org/10.1080/08120099.2025.2588307