LANDSCAPE EVOLUTION MODELS OF AUSTRALIA SINCE THE CRETACEOUS USING COUPLED CLIMATE, SURFACE PROCESS, TECTONIC, AND GEODYNAMIC MODELS

Recent advances in numerical modelling of landscape evolution on geological timescales has produced a new generation of evolving Australian paleogeographic simulations for times since the Jurassic. These models have enabled us to explore the role and relative contributions of climate, flexure, mantle-driven dynamic topography, and geodynamics.

The Australian continent records a ~40° change in latitude over the last 100 million years, and most notably, Australia’s entrance into the near-equatorial humid belt in the last ~30 million years. Concurrently, sea level was dramatically changing (particularly since Antarctic glaciation at ~35 Ma), while the Australian continent was overriding a region of dynamic subsidence, driven by the sinking of slabs related to Australia, Eurasia, and Pacific plate convergence.

Although modelling these processes together would have been prohibitive just a few years ago, recent advances have enabled us to link these open-source community modelling ecosystems. We use GPlates for the plate tectonic and paleogeographic reconstructions, which also allows us to make use of published paleo-climate model outputs, while also enabling us to run our own intermediate complexity climate models. Paleogeographic reconstructions are also modulated by the regional dynamic topography signal, which we derive from coupled GPlates-CitcomS models of plate tectonics and mantle flow. We also apply the carbonate growth module in pyBadlands to evaluate the role of changing sea levels, lithospheric elastic thickness, climate regimes, and tectonic events on the evolution of carbonate platforms and massive reef systems on the Australian continental margins.

The resulting 4D models (space+time) capture the evolution of the Australian landscape and the continental margins in unprecedented detail, capturing both the erosion, transport, and deposition of sediments. Importantly, these community models help us address basic research questions (such as the role of eustasy, isostasy, etc.), but are also increasingly important for industry applications in assessing the preservation potential of ore deposits, as well as the fate of sedimentary mineral deposits.