Testing the reliable proxies to understand the mid-Holocene climate variability records from Chandratal lake, Western Himalayas

Abstract

Chandratal lake (32°28′30.65″ N 77°37′1.42″ E) located at the junction of Indian Summer Monsoon and Westerlies in the Northwestern Himalaya give an opportunity to reconstruct climate variability over the last ~6300 cal yr BP. Here, we used multi-proxy (Amino acids, Biogenic silica, grain size and total organic carbon) to link climate change and organic burial during the mid-Holocene period. The proxy records captured the changes in monsoon patterns, linking with Holocene climate optimum (HCO) during the ~6344- 5821 cal BP. The sediment profile begins with a wetter and moist climate mostly from the terrestrial environment inputs, corresponding to the warm Holocene Climate Optimum (HCO) period (~6344 - 5821 cal yr BP). A stable condition of the geochemical proxies during ~5821-3780 cal yr BP reveals a shifting of a moisture source, catchment stability and cold/dry climate in correspondence with reduced precipitation.The period from ~3780 to 2129 cal yr BP, follows a gradual increase of organic matter deposition and supported with an elevated atomic C/N ratio of 13.1 (mean value). Further association of organic matter with the coarser grain particles, suggesting a wetter climate from increasing runoff which is in correlation with the reinforcement of the precipitation during this time interval. From ~2129 to 696 cal yr BP, reduced precipitation/dry condition was observed with a shift in the autochthonous production of organic matter (C/N ratio of 8.91). Increase in BSi content suggests an ameliorated climate at this interval; however, the lower organic matter content (mean, 1.79%) and shift in the correlation of organic matter from coarse grains to finer grain size, suggesting little contributions from the terrestrial activities favouring the dry environment and abundant diatoms growth. The paleoenvironmental variations illustrate in the study is comparable to other findings recorded in the Himalayan region.