Mid–late Holocene palaeoclimate and biogeochemical evolution of Wular Lake, Kashmir Valley, India

Abstract

Continuous multiproxy data were generated to understand the mid–late Holocene palaeoenvironmental history of the Kashmir Valley and the biogeochemistry of Wular Lake, India. For this purpose, geochemical and stable isotopic analyses were carried out on sediment samples retrieved from a 160 cm long trench excavated on the eastern bank of Wular Lake located in the Union Territory of Jammu and Kashmir, India. The chronology of the sediment strata developed using ¹⁴C dating by accelerator mass spectrometry covered the last ~5600 yr  bp. Our results indicated the occurrence of an extended dry climate phase from 4600 to 3800 yr  bp, which coincided with the widely recognised Meghalayan Stage, when major civilisations like the Harappa and the Akkadian were known to collapse. The lake biogeochemistry revealed dominance of the emergent macrophytes during this stage. Another dry phase was observed between 3100 and 2200 yr  bp. This dry phase peaked at around 2900 yr  bp, coinciding with Bond Event 2. Wular Lake faced nutrient limitation due to low runoff around 2500 yr  bp caused by the persistent dry and cold climate. Geochemical signatures revealed that anthropogenic activities during the last two millennia might have significantly influenced erosion in the catchment area.