Quaternary of the Thar Desert in India: understanding the history of dune accumulation with the aid of Optically Stimulated Luminescence (OSL) dating
Aayush Srivastava is a doctoral student at the School of Geography and the Environment as a member of the Oxford Luminescence Dating Laboratory.
He holds a BSc(Hons) degree (with distinction) in Geology from the University of Delhi (2013). Most recently, he received his MSc degree (with distinction) in Quaternary Science from University of London (2015). His MSc thesis focussed on exploring the feasibility of Infra-red Stimulated Luminescence (IRSL) Dating and its application to fluvial sediments from a Middle Palaeolithic site in Armenia.
- Quaternary Climate and Environment changes
- Drylands Environments
- Optically stimulated luminescence dating techniques
- Sedimentology and geochemistry
Awards and Funding
- Clarendon Fund Scholarship, University of Oxford - 2015-18
- Hertford College Graduate Scholarship - 2015-18
- International Excellence Award, Royal Holloway, University of London - 2014
- University Gold Medal (Bachelor of Science), University of Delhi - 2013
- College Gold Medals (Geology), Hans Raj College, Delhi - 2010-13
For his doctoral research, Aayush is doing a detailed palaeoenvironmental analysis of the Thar Desert in India by establishing a geochronology of aeolian accumulations during the late Quaternary period. It will include use of OSL dating applications and modelling to establish and further develop the dune accumulation records as proxies of desert climate change.
The Thar Desert, NW India, the most densely populated desert in the world, lies at the limit of the region receiving precipitation from the Indian (summer) monsoon, with a modern mean NE-W rainfall gradient of 400mm to less than 200m. It is generally accepted that insolation driven changes in monsoon intensity have affected desert contraction and expansion during the late Quaternary, impacting on the construction and activity of aeolian landforms. Therefore, the extensive Thar Desert dune systems are potentially a rich archive of past climatic and geomorphological change. Whilst a small number of studies have undertaken geochronological investigations of dunes using luminescence dating, studies have been sporadic and opportunistic, and have tended to rely on older dating protocols. A systematic sedimentary and chronometric investigation of the Thar Desert dunes would for the first time allow an analysis of the spatial variations in Thar dune accumulation histories.
Figure 1 (left): Aayush Srivastava collecting sand samples for OSL dating at a dune pit in the Thar Desert, Rajasthan, India (March, 2016).
Figure 2 (right): Sampling for OSL analysis (Thar Desert, India; March 2016). Light proof tubes (~ 5cm diameter, ~15 cm length) are hammered horizontally into the clean vertical face of a pit. The tubes, when full, are capped and sealed in lightproof bags. Samples are then processed in the lab under subdued light conditions.
The primary aim of this study therefore is to investigate fundamental aspects of the Late Quaternary accumulation history of the Thar Desert dunes, including testing whether spatial variations in dune accumulation have occurred. As it is essential to establish detailed accumulation records to achieve this aim, the study focusses on two areas in detail along the modern rainfall gradient. Fieldwork includes sampling for geochronological (OSL), sedimentological and provenance analysis. This will allow detailed accumulation histories to be established and permit the assessment of the roles of changing sediment supply and/or monsoon intensity in the late Quaternary development of the Thar Desert.