High-density chronology of dune accumulation in the Thar Desert using integrated luminescence approaches

Description

The Thar Desert is unique in hosting a diverse range of sand dune types within a relatively small area, yet their accumulation history—particularly in the western Thar—remains poorly understood (Srivastava et al., 2019). This study demonstrates the application of a high-density luminescence dating framework to reconstruct ~40 ka of dune accumulation across a 330 km N-S transect in the arid western Thar Desert, India. By integrating nine new laboratory-determined OSL ages with 456 rapid age estimates derived from a portable luminescence reader, we present the most comprehensive chronology of aeolian deposition in the region to date. This study builds on the work of Nitundil et al. (2023) in this region. Of the rapid estimates, 205 are from deep auger profiles reaching depths of up to 11 meters, and these are from a range of dune types including linear (10 profiles), parabolic (3 profiles), transverse (1 profile), and barchan (4 profiles), with the latter two being studied for the first time using modern dating techniques in the Thar.

This methodological integration allows us to resolve spatial and temporal patterns of sediment deposition with unprecedented detail. We identify an extensive Holocene accumulation phase centered at 7.7 ka and underlying more recent activity in the upper sediment layers. In the barchan dunes, this active sediment reaches depths of ~6 meters. In contrast, linear and transverse dunes show significantly shallower active zones (<1.5 meters). The spatial variability in younger dune dynamics reflects regional gradients in aridity, vegetation cover, and sediment availability, leading to localized differences in reactivation intensity and frequency. Isolated older deposits dating to ~23 ka and 44 ka in a linear dune represent the oldest known aeolian sediments in the western Thar and suggest a previously undated dune activity phase.

Our results highlight the power of coupling rapid, field-based portable luminescence screening with conventional OSL dating to efficiently characterize dune depositional histories. The approach greatly enhances sampling density and resolution while maintaining chronological reliability, making it especially valuable for large-scale geomorphic reconstructions in arid environments. This case study underscores the potential for portable luminescence measurements to complement laboratory methods in future geochronological investigations that benefit from a detailed accumulation assay such as localized studies of dune development and evolution to enhance our understanding of sedimentary processes in arid environments.

Period	20 Aug 2025 → 22 Aug 2025
Event title	UKLum 2025
Event type	Conference
Location	St AndrewsShow on map
Degree of Recognition	International