In recent years there has been a considerable expansion of deployments of portable seismic stations across Australia, which have been analysed by receiver function or autocorrelation methods to extract estimates of Moho depth. An ongoing program of full-crustal reflection profiles has now provided more than 25,000 km of reflection transects that have been interpreted for Moho structure. The Moho dataset is further augmented by extensive marine reflection results. These new data sources have been combined with earlier refraction and receiver function results to provide full continental coverage, though some desert areas remain with limited sampling. The dense sampling of the Moho indicates the presence of rapid changes in Moho depth and so the Moho surface has been constructed using an approach that allows different weighting and spatial influence depending on the nature of the estimate. The inclusion of Moho results from gravity inversion with low weighting helps to resolve the continent-ocean transition and to provide additional control in the least sampled zones. The refined distribution indicates the presence of widespread smaller-scale variations in Moho structure. Strong lateral contrasts in crustal thickness remain, but some have become more subdued with improved sampling of critical areas. The main differences from earlier results lie in previously poorly sampled regions around the Lake Eyre Basin, where additional passive seismic results indicate somewhat thicker crust though still witha strong contrast in crustal thickness to the cratonic zone to the west. Appeared in Geophysical Journal International, January 2023

<div><strong>Output Type: </strong>Exploring for the Future Extended Abstract</div><div><br></div><div><strong>Short Abstract: </strong>The continental crust directly hosts or underlies almost all mineral resources on which society depends. Despite its obvious importance its structure is poorly characterised. In particular, its density is surprisingly poorly constrained because it is difficult to directly image from the surface. Here we collate a global database of crustal thickness and velocity constraints. In combination with a compilation of published laboratory experimental constraints on seismic velocity at a range of pressures, we develop a scheme with which to convert seismic velocities into density as a function of pressure and temperature. We apply this approach to the Australian crystalline basement. We find that the Australian crust is highly heterogeneous, ranging in bulk density from 2.7—3.0 g cm-3. Finally, we explore the utility of our database for testing hypotheses about the location and endowment of mineral resources using porphyry copper deposits as an example. Our results provide an improved framework with which to explore the subsidence and thermal evolution of sedimentary basins, as well as probing relationships between deposit types and crustal architecture.</div><div><br></div><div><strong>Citation: </strong>Stephenson, S.N., Hoggard, M.J., Haynes, M.W., Czarnota, K. & Hejrani, B., 2024. Constraints on continental crustal thickness and density structure. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://doi.org/10.26186/149336</div>