Paleohydrology Reconstruction for the Last 30 Kyr Based on Groundwater Dating, Thar Desert, Western India

Radiocarbon ( 14 C) ages of groundwater from several aquifers of the arid Jaisalmer District, Northwestern India (part of the Thar Desert) were investigated to reconstruct the hydrological history of the Thar Desert. The Thar Desert and its surrounding regions have been extensively studied for palaeoclimatic reconstruction, but there remains gap in the knowledge about palaeoclimate of the Thar Desert beyond Holocene. An attempt has been made to understand the hydrological history of the Thar Desert based on the radiocarbon dates of the groundwater samples extending from 30 kyr B.P. to present. Four major palaeohydrological / palaeoclimatic periods were identified during the last 30 kyr. Pre-LGM (30−27 kyr B.P.) has been identified as a weak monsoon period and the LGM (27−18 kyr B.P.) is distinctly identified as “recharge gap” in the study area indicating persistent dry phase. The Late Glacial/early Holocene (18−5 kyr B.P.) is marked by continuous recharge events indicating a wet phase in Thar Desert. The late Holocene (5−0 kyr B.P.) has been identified as a dry phase attesting to the present onset of aridification in Thar Desert since 5 kyr B.P. This study demonstrates the potential of groundwater recharge age as a proxy for palaeoclimatic study in arid region