Dynamic Reconstructions of Basins in Australia: Stratigraphic Constraints on Cretaceous to Cenozoic Mantle Convection

Histories of vertical lithospheric motion preserved in sedimentary basins provide constraints on evolving mantle buoyancy and convection histories. We present a quantitative analysis of subsidence, exhumation and stratigraphic hiatuses to constrain mantle dynamics during the Cretaceous–Cenozoic, illustrated by case studies from northwestern Australia. Basin analysis across multiple basins from this region calculates the continental-scale vertical response to evolving geodynamic forces, from Jurassic–Cretaceous subsidence during sub-basin development associated with rifting and Gondwana breakup to the recent northeastward tilting of Australia driven by dynamic topography linked to slab subduction beneath the Indonesian margin.

In particular, our kinematic reconstructions of the Northern Carnarvon Basin quantify Jurassic–Cretaceous nearshore intraplate rift-extension rates (~8 mm/yr), with rift cessations at ~155 and ~120 Ma coinciding with major Gondwana breakup events. This temporal correspondence demonstrates strong coupling between far-field plate reorganisations and regional vertical and lateral motions and constrains lithospheric controls on strain localisation during Gondwana breakup events.

Integration of compaction and paleothermal data identifies two significant Mesozoic exhumation episodes that correlate spatially with mapped magmatic bodies, implying that thermal perturbations from sub-lithospheric sources drove regional uplift. Jurassic–Early Cretaceous NE–SW gradients in uplift and exhumation shoe dynamically evolving magmatic systems, associated with the Kerguelen and Exmouth plumes. In addition, we present uncertainty propagation analysis. This analysis indicates that robust coverage and high-quality data on the Northwest Shelf reduces uncertainty in subsidence and exhumation estimates, thereby increasing our confidence in the results and conclusions from this study.