RSES Seminar Series 2024-07-18 Morgan Blades (University of Adelaide)

Half a billion years of basin evolution in northern Australia; the greater McArthur Basin
Morgan Blades (University of Adelaide)

Abstract: Northern Australia contains a series of extensive Proterozoic basin systems that span from the Palaeo- to Mesoproterozoic: the greater McArthur Basin (McArthur Basin, Birrindudu Basin, Tomkinson Province), the South Nicolson Basin, and the Isa Superbasin. These systems have been interpreted to be of equivalent age and deposited under similar climatic conditions, resulting in correlative successions. This basin system covers much of northern Australia and possibly extends as the Yanliao Basin across to North China, which lay off northern Australia when the basin formed — ca. 1820–1325 Ma. Not only does this sedimentary system preserve half a billion years of Earth's history, it is a vast exploration province for basin-hosted resources, both hydrocarbons (oil and natural gas) and metals (critical metals [e.g. rare earth elements, Co], Cu, Pb, Zn and Au). Hydrocarbon and metal deposits in the basin are largely controlled by the host sediment composition and ‘redox traps’, these are in-turn moderated by seawater chemistry, biological activity and tectonism. However, these controls are not fully understood or constrained.

In order to better understand the basin evolution, we follow a number of approaches, including:

1. Using newer geochronological laser-based techniques, such as Rb–Sr in shales U–Pb in carbonates, to assist with intra-basinal correlation, thermal and hydrothermal overprint history.

2. Using detrital chronology to understand the potential source areas for the basin.

3. Investigating the available geochemical chemical proxies that relate to bio-productivity, salinity/restriction, and redox — temporally and spatially.

4. Building a reconstruction of the basin, and of the tectonic geography of the basin.

In this talk I will present aspects from all of these approaches and how they have helped understand the evolution of the greater McArthur Basin.