Scaling-up dune dating: Integrating portable and laboratory luminescence in the Thar Desert, India

Reconstructing windblown dune accumulation is often constrained by the high cost and low spatial resolution of traditional geochronological tools. In this study, we demonstrate how the integration of high-throughput, field-based portable optically stimulated luminescence (port-OSL) with conventional laboratory OSL dating can transform our ability to reconstruct landscape-scale aeolian system behaviour. Applied to the arid western Thar Desert, this hybrid approach yields the most detailed chronology of dune accumulation patterns in the region to date.<br/>Across a 330 km north–south transect, we combine nine new laboratory-determined OSL ages with 456 port-OSL age estimates, enabling a high-density reconstruction of aeolian deposition. This follows a calibration of the port-OSL signals in the region (Nitundil et al., 2023). Of these, 205 age estimates come from deep auger profiles (up to 11 m) within linear (10), parabolic (3), transverse (1), and barchan (4) dunes—marking the first use of OSL dating in transverse and barchan dunes within the Thar. By dramatically increasing sample density both spatially and vertically, this integrated framework helps resolve phases of sediment accumulation more efficiently, which after lab-based calibration, requires no further laboratory instrumentation.<br/><br/>Our results highlight a widespread Holocene accumulation phase centered around 7.7 ka and reveal variable depths of recent sediment activity—from ~ 6 m in mobile barchans to &lt; 1.5 m in linear dunes. Isolated sedimentary units of older age, ~ 23 ka and ~ 44 ka, extends the known aeolian accumulation history in this region. The variability in accumulation patterns across dune types reflects interactions between sediment supply, wind regime, and vegetation cover—key controls on aeolian bedform evolution.<br/><br/>By balancing reduced age precision with increased sample numbers and spatial coverage, this integrated approach offers a scalable, efficient strategy for reconstructing aeolian accumulation histories. It opens new opportunities to interrogate dunefield morphodynamics at landscape scales. Our results not only expand the temporal record of dune activity in the Thar Desert but also demonstrate how port-OSL can reshape the way we investigate aeolian systems.