Quantifying the basin dynamics of the Proterozoic Carrara Sub-basin to understand the assembly and evolution of the Australian continent

Abstract

Formed around the time of the Nuna supercontinent, the South Nicholson region is part of a resource-abundant region in Australia and is also a rich source of sedimentary information about the development of the Australian continent and associated supercontinents, from Nuna to Rodinia and Gondwana. In this paper, we analyse the recently acquired data across the Carrara Sub-basin in the central South Nicholson region, which includes five seismic lines (17GA-SN) and a new well (NDI Carrara 1). The analysis of the data utilises decompaction and backstripping techniques to assess tectonic subsidence and calculate maximum burial depths. These results are calibrated using vitrinite reflectance data to quantify the erosional history of the basin. As a result, we identified five phases of subsidence and four erosional events within the South Nicholson region during the Proterozoic and Paleozoic periods. The Proterozoic formations reached a maximum burial depth of up to 7500 m, which concluded with the Isan Orogeny $\sim$1.6 Ga, likely initiating an uplift and erosional event during the collision of Laurentia and Australia. Our results indicate that $\sim$2600 m of erosion occurred from this event to $\sim$540 Ma. In the Early Cambrian, from 540 Ma to $\sim$500 Ma, significant subsidence occurred again, with the newly formed Neoproterozoic sediments reaching a maximum burial depth of 2000 m. This subsidence event was concurrent with the extension related to the breakup of Rodinia. Subsequently, from the Late Ordovician to the Early Cretaceous, we calculate that $\sim$600 m of erosion occurred, concurrent with the Alice Springs Orogeny. This erosional surface is overlain by only $\sim$6 m of Cenozoic sediment cover. Our results quantify the sedimentary history of the South Nicholson region and connect its evolution to the tectonic processes shaping Australia since 1.6 Ga. These results provide insights into the broader supercontinental cycles of Nuna, Rodinia, and Gondwana.