C01_P03

Evidence of Holocene Hydroclimate Variability in Northern India and Links to the Indus Civilization

Cherkinsky A¹, Niederman E², Porinchu D¹, Kotlia B³

¹University Of Georgia, Athens, United States, ²Stetson University, Deland, United States, ³Kumaun University, Nainital, India

Multi-proxy analysis of a lake sediment core from Uttarakhand, India was undertaken to: characterize regional hydroclimate variability during the middle to late Holocene; and determine if evidence of Indus civilization characterized by well developed agriculture between 4200-3900 cal yr is present at the site. Deoria Tal is a small (2.7 ha), moderately deep (16.0 m), tectonically formed lake situated in a high-grade metamorphic terrain above the Main Central Thrust zone in the Garhwal Himalaya. Chronological control is based on ten AMS ¹⁴C dates obtained on Trapa seed cases. The age-depth model, developed using BACON, indicates that the core spans ~ 5300 years and that a notable increase in the sedimentation rate occurs at 2100 cal yr BP. The results of non-destructive, radiological analyses (XRF, CT scans) suggest that elevated detrital input, greater sediment density, decreased lake ventilation, and lower autochthonous productivity, reflecting a deepening of the lake, occurred between 4350 and 4200 cal yr BP.  An abrupt shift in elemental concentrations and sediment density indicated the onset of lake drawdown at 4200 cal yr BP and a negative hydroclimate anomaly between 4200 and 4050 cal yr BP. At present, we cannot distinguish if the hydroclimate anomalies identified at Deoria Tal are due to variations in summer and/or winter precipitation; however, it is notable that the positive hydroclimate anomalies at Deoria Tal are associated with intervals of strengthened mid-latitude Westerlies.