Evidence of abrupt hydroclimate and environmental change in the Garhwal Himalaya, India through an application of non-destructive, radiological methodologies to lacustrine sediment

Non-destructive, radiological imaging approaches were applied to a 3.80 m long sediment core recovered from Deoria Tal, a mid-elevation lake located at 2393 m a.s.l. in the Garhwal Himalaya, India to characterize abrupt climatic fluctuations. Ten AMS 14C dates indicated that the core extends back to 5200 cal yr BP and were used to calibrate the results from the X-ray fluorescence (XRF), X-ray, and CT scans. Anomalous hydroclimate episodes, evidenced by variations in elemental concentrations and sediment density, are centered at 4850, 4200, and 3100 cal yr BP. The 4850 and 4200 cal yr BP events were initially characterized by elevated detrital input, greater sediment density, and decreased lake ventilation, reflecting elevated lake level. The 3100 cal yr BP event was characterized by lower detrital flux, decreased sediment density, and increased oxygenation, reflecting lake drawdown. The hydroclimate record was compared with archeological evidence of regional civilization and cultural change.