Is there evidence for global‐scale forcing of Southern Hemisphere Quaternary desert dune accumulation? A quantitative method for testing hypotheses of dune system development

Abstract

Luminescence dating of desert dune sediments has generated many hundreds of ages, many used in reconstructions of Quaternary environmental changes, others in attempts to elucidate dune processes. Environmental and climatic interpretations of these records have proved problematic and it remains challenging to test hypotheses of the systematic response of dunefields to changes in external forcing in the past and to make predictions of the future. We use a method that quantifies dune sediment accumulation to interpret dune luminescence age datasets, rather than simply using the ages themselves as proxies of change. The Accumulation Intensity method allows periods of dune sediment accumulation, here over the timescale 102–105 years, to be identified from compilations of dated sand sea stratigraphic sequences. We apply this approach to two of the largest dune age datasets, from southern Africa and Australia, testing whether or not dunefield accumulation has co‐varied in the Late Quaternary and whether systematic relationships to external drivers at global, hemispheric, regional and local scales can be identified. Copyright © 2017 John Wiley & Sons, Ltd.

Analysis of late Quaternary dunefield development in Asia using the accumulation intensity model

“…ARV was run with various environmental scenarios to simulate the effects of long term changes in aeolian dynamism on subsequent deposition, preservation and erosion on dune sedimentary bodies, which are the source of sediments for dating. The revised AI model (Thomas and Bailey, 2017) was expressly developed to allow temporal changes in dune accumulation to be calculated through time from empirical data, in a manner independent of the number of samples included in an analysis, but representative of changes in accumulation rates present within a dataset. The method can be applied to records integrated over a landscape scale, i.e.…”

“…climatic) forcing or whether sedimentation is dominated by autogenic (internal system) drivers (Jerolmack et al, 2012). Recently evaluated by Thomas and Bailey (2017), there is good evidence for the prerservation of exoigenic signals where the sediments of extensive continental dune systems are concerned. Fourth, taphonomic effects mean that not all older deposits are preserved, as deposited sediments can be removed in subsequent dune activity events or periods (Bailey and Thomas, 2014).…”

“…Taking the quantitative approach to understanding dated dune stratigraphies of Bailey and Thomas (2014), a numerical model has been developed to utilise chronometric and sedimentological data from individual dunefields to generate 'Accumulation Intensity' (AI) records of dunefield sediment accumulation through time (Thomas and Bailey, 2017). In this paper we apply the AI methodology to dune age records from Asian dune systems (Figure 1), allowing for the first time both a systematic analysis and comparison of the timing of dune accumulation through the continent's drylands and an assessment of the quality of regional data sets.…”

“…Numerical analysis of age records has led to the testing, and abandonment, of global models of desert dune development (Thomas and Bailey, 2017). Luminescence dating of desert dunes sediments has provided the means to recognise temporally-complex dunefield accumulation records and multi-phase constructional histories within regional dune systems (Singhvi and Porat, 2008;Thomas and Burrough, 2012).…”

Deep learning for dune pattern mapping with the AW3D30 global surface model

“…Wiggs et al, 1995Wiggs et al, , 1996Telfer, 2011;Craddock et al, 2015;Hesse et al, 2017) and the geochronology of linear dune deposits (e.g. Telfer and Hesse, 2013;Hesse, 2016;Thomas and Bailey, 2017), linear dune formation remains a poorly understood process. Broad descriptive studies of linear dune planforms (e.g.…”