Palaeoclimatic variability during last eight millennia from a morainal lake in Zanskar, northwest Himalaya, India

Abstract

Centennial–scale palaeoenvironmental variability has been deduced during past eight millennia using multi–proxy study (textural analysis, environmental magnetic parameters, stable carbon isotopes, palynofacies and elemental concentration), from Khangok–Padam in Zanskar Valley, northwest Himalaya. The multi–proxy record from this morainal lake spanning last ~8200 cal years BP has revealed four hydroclimatic phases. The overall progressively improving hydroclimatic trend is indicated by multi proxy study: sediment size/texture (as a proxy for the energy condition and depositional environment), mineral magnetism (proxy for sediment flux or lithogenic input and lithologic variation), carbon isotope signature (δ13Corg) preserved in organic constituents of sediments (a proxy for palaeovegetation and climate change), elemental geochemistry (proxy for weathering and erosion) and selected samples for palynofacies data (a proxy for changes in biological organic matter). This improving hydroclimatic trend is however punctuated by an abrupt wet spell at ~6200–5200 cal years BP and relatively drier climate during the Little Ice Age between 1400 and 1900 CE. The main driving force implicated for the changes are seen to be the solar output variations. The area lying in a transitional climatic zone of NW Himalaya shows no emphatic record of the events like the 4200 cal. years BP, 2600 cal. years BP and Holocene Climatic Optima. Contrary to the earlier studies in the region (e.g., Tsokar and TsoMorari), our results show an improving hydroclimatic condition in this transition climatic zone between the Indian Summer Monsoon dominated Higher and westerly dominated Trans Himalaya.