The Cosmolian program for simulating aeolian dynamics and its application to central Australia

Abstract

The wide spatial coverage of sand dunes in continental interiors makes the understanding of their activity and accumulation history valuable for palaeoenvironmental reconstructions and the interpretation of landscape evolution. Nevertheless, the study of aeolian landscape development at the million‐year timescale is hampered by the complex interaction of factors determining dune migration and the inherently self‐destructive nature of their chronostratigraphy, thus limiting the applicability of traditional dating methods. This study presents a standalone program that simulates aeolian transport based on luminescence‐derived chronologies coupled with numerical modelling of the accumulation of cosmogenic nuclides. This integrative approach to modelling the history of aeolian landforms reveals phases of emergence of aeolian sand into the landscape, and provides a data‐based scheme that facilitates the morphodynamical study of aeolian processes over multiple timescales and up to several millions of years. The application of the program for reanalysing previously reported data from the Australian Simpson Desert reveals multiple pulses of sand dispersion into central Australia at 3.8–3.4, 2.9–2.5 and 1.5–1 Ma, corresponding to pronounced changes in climatic conditions and landscape deformation events. The synchronicity of the results with the established environmental framework that would promote the production and aeolian distribution of sand exemplifies the applicability of process‐based modelling in constructing a timeframe of key landscape evolution events in arid environments by studying aeolian deposits. The dependence of the parameters used to determine environmental settings on sand transportation patterns additionally makes the program a powerful tool to further investigate the triggers and mechanisms of aeolian processes.

Chronology of sedimentation and landscape evolution in the Okavango Rift Zone, a developing young rift in southern Africa

“…Collectively, this points to the preservation of the older sediments on the higher margins of the tectonic trough of the CE and the incorporation of more recently eroded material downwards into the evolving basin. (Vainer et al, 2018;Vainer and Ben Dor, 2021). The probability plots show successful runs in which simulated concentrations of 26 Al and 10 Be simultaneously matched with their analytical values.…”

“…The surficial residence time of the sand was assessed through numerical modelling simulating the accumulation of cosmogenic nuclides under eolian, fluvial, or lacustrine settings by applying the Cosmolian model (Vainer et al, 2018a;Vainer and Ben Dor, 2021;Vainer et al, 2022).…”

“…While the different combinations of scenarios generally converge into a distinct peak, several samples present a bi-modal distribution with a relatively narrow combined range or positive skewness. These are probably the outcome of grains within the same sample with different sources and transportation histories (Vainer and Ben Dor, 2021), and this variance is reflected in the uncertainty estimation.…”

“…OSL modelling for estimating dose rate and depositional age was performed via Mauz and Hoffmann (2014) Kreutzer et al (2012, 2019. Cosmogenic nuclides modelling for residence time estimation was done using Cosmolian (Vainer and Ben Dor, 2021).…”

“…The size of the graduated symbols increases with larger values. (b) Kernel density estimates of the sedimentary residence time of sands, simulated with the Cosmolian Model(Vainer et al, 2018;Vainer and Ben Dor, 2021). The probability plots show successful runs in which simulated concentrations of 26 Al and 10 Be simultaneously matched with their analytical…”