TY - CONF
T1 - Investigating records of dune activity in the Thar Desert, India by using portable luminescence techniques
AU - Nitundil, Shashank
AU - Stone, Abi
AU - Srivastava, Aayush
AU - Kinnaird, Tim
AU - Songara, Komal
PY - 2022/9/7
Y1 - 2022/9/7
N2 - The densely populated Thar Desert, India has a complex dune developmental history with high spatio-temporal variability, necessitating dunefield-scale investigation with sufficient sampling resolution to provide insights into dune accumulation history. However, establishing dune accumulation histories using traditional chronological techniques is costly, laborious and resource intensive. This study utilises rapid-age estimates, derived from calibrated port-OSL measurements, to overcome this limitation.265 samples were collected from ten linear dunes on a 100 km transect in western Thar, a hyperarid region that lacks robust dune chronologies. Port-OSL measurements, in terms of IRSL to BSL signal ratios (0.29 to 0.35), along with particle size analysis (moderately well sorted medium to fine sand) suggests a similar sedimentology and provenance for all samples collected. This established the feasibility of using calibrated port-OSL measurements for rapid age estimates in the Thar Desert. Calibration of the port-OSL measurements was carried out using ages of samples with previously established chronologies from central Thar (n=40) [1,2] as well as newly dated samples collected as part of this study (n=4) and showed a good fit (R2=0.85). Based on calibration, all 256 samples were estimated to date to the Holocene period ranging between 150 and 11000 years old that correspond to BSL totals of 0.2 million and 14 million counts as measured from the port-OSL reader. Rapid age-estimates of all samples were then used to investigate the records of dune activity. Eastern flanks were found to be younger and have a higher accumulation rate than the western flanks over the last 3000 years, suggesting that the dunes are likely moving eastward. A period of high accumulation was found between ~ 8 - 6 ka in six of the dunes, corresponding to the Holocene warm period wherein the Indian summer monsoon (ISM) winds were stronger [3].This study is the first to establish a detailed luminescence chronology in hyperarid Western Thar. It is also the first to utilise a combined approach of traditional laboratory based OSL and port-OSL to rapidly estimate sediment depositional ages in the Indian subcontinent. The calibrated port-OSL paves the way for large spatial scale studies at high sampling resolution to understand dune processes and reconstruct palaeo-dune activity and palaeoenvironmental conditions in the region.[1] Srivastava A, Thomas D, Durcan J. Holocene Dune Activity in the Thar Desert, India. Earth Surface Processes and Landforms. 2019; 44(7):1407-1418.[2] Srivastava A, Durcan J, Thomas D. Analysis of late Quaternary linear dune development in the Thar Desert, India. Geomorphology. 2019; 344:90-98.[3] Jiang W, Leroy S, Yang S, Zhang E, Wang L, Yang X et al. Synchronous Strengthening of the Indian and East Asian Monsoons in Response to Global Warming Since the Last Deglaciation. Geophysical Research Letters. 2019; 46(7):3944-3952.
AB - The densely populated Thar Desert, India has a complex dune developmental history with high spatio-temporal variability, necessitating dunefield-scale investigation with sufficient sampling resolution to provide insights into dune accumulation history. However, establishing dune accumulation histories using traditional chronological techniques is costly, laborious and resource intensive. This study utilises rapid-age estimates, derived from calibrated port-OSL measurements, to overcome this limitation.265 samples were collected from ten linear dunes on a 100 km transect in western Thar, a hyperarid region that lacks robust dune chronologies. Port-OSL measurements, in terms of IRSL to BSL signal ratios (0.29 to 0.35), along with particle size analysis (moderately well sorted medium to fine sand) suggests a similar sedimentology and provenance for all samples collected. This established the feasibility of using calibrated port-OSL measurements for rapid age estimates in the Thar Desert. Calibration of the port-OSL measurements was carried out using ages of samples with previously established chronologies from central Thar (n=40) [1,2] as well as newly dated samples collected as part of this study (n=4) and showed a good fit (R2=0.85). Based on calibration, all 256 samples were estimated to date to the Holocene period ranging between 150 and 11000 years old that correspond to BSL totals of 0.2 million and 14 million counts as measured from the port-OSL reader. Rapid age-estimates of all samples were then used to investigate the records of dune activity. Eastern flanks were found to be younger and have a higher accumulation rate than the western flanks over the last 3000 years, suggesting that the dunes are likely moving eastward. A period of high accumulation was found between ~ 8 - 6 ka in six of the dunes, corresponding to the Holocene warm period wherein the Indian summer monsoon (ISM) winds were stronger [3].This study is the first to establish a detailed luminescence chronology in hyperarid Western Thar. It is also the first to utilise a combined approach of traditional laboratory based OSL and port-OSL to rapidly estimate sediment depositional ages in the Indian subcontinent. The calibrated port-OSL paves the way for large spatial scale studies at high sampling resolution to understand dune processes and reconstruct palaeo-dune activity and palaeoenvironmental conditions in the region.[1] Srivastava A, Thomas D, Durcan J. Holocene Dune Activity in the Thar Desert, India. Earth Surface Processes and Landforms. 2019; 44(7):1407-1418.[2] Srivastava A, Durcan J, Thomas D. Analysis of late Quaternary linear dune development in the Thar Desert, India. Geomorphology. 2019; 344:90-98.[3] Jiang W, Leroy S, Yang S, Zhang E, Wang L, Yang X et al. Synchronous Strengthening of the Indian and East Asian Monsoons in Response to Global Warming Since the Last Deglaciation. Geophysical Research Letters. 2019; 46(7):3944-3952.
M3 - Poster
T2 - UK Luminescence and ESR meeting 2022
Y2 - 7 September 2022 through 9 September 2022
ER -