CLIMATE AND SEISMICITY IN THE HIGHER CENTRAL HIMALAYA: EVIDENCES FROM GARBYANG BASIN, UTTARANCHAL, INDIA

Relict lake deposits at Garbyang in the Trans-Himalaya have preserved a rare combination of records of climate and seismicity.In the present study, magnetic susceptibility, geochemistry, luminescence and radiocarbon dating techniques along with conventional sedimentological parameters were used to deduce past climatic and seismic events. The results suggest that the Trans Himadri Fault (THF) controlled the extent of past glaciers and impounded rivers giving rise to lakes. Subsequent sedimentation preserved near continuous record of regional events spanning the late Quaternary.

The upper 28.40m lacustrine sediments were Optically dated to ~20 ka to ~ 10 ka. Changes in magnetic susceptibility and elemental concentration in levels corresponding to 13±2 ka to 11±1 ka provide a first evidence of Younger Dryas cooling from Indian sub-continent. The study further demonstrates that the radiocarbon ages on organic carbon from predominantly limestone terrain suffers from hard water effect and is therefore overestimated the real age. This implies that all the radiocarbon ages from lime tone terrains in Himalya, need a revisit using more secured methods like Optical dating.