Late Holocene development of Lake Rangkul (Eastern Pamir, Tajikistan) and its response to regional climatic changes

Abstract This study was aimed at collecting and examining a sediment core from Lake Rangkul (Eastern Pamir, Tajikistan) to better understand the lake's development and to assess past variations in climatic conditions in this particular area in comparison with data available from other lakes from the neighboring locations. For the purposes of this study, we performed detailed geochemical and palynological analyses on the sediment core taken from Lake Rangkul in 2014. Moreover, we obtained historical satellite and meteorological data and performed field tests for ground ice presence to identify trends in recent lake development. We distinguished 5 distinct stages over the past 2000 years of the lake's history that differ in geochemical and palynological characteristics. Despite the fact that Lake Rangkul is shallow and sensitive to various disturbances in sedimentation, the recorded stages are in accordance with general climatic trends observed for the Northern Hemisphere in the Late Holocene. Satellite data from the past 45 years shows a noticeable increase in the lake's area, which coincides with rising air temperatures. As the lake is located in the permafrost region with ground ice present immediately below the soil surface, its functioning is influenced by permafrost thawing, which will lead to future changes in the lake area and the distribution of surrounding wet meadows, used as pastures by local inhabitants.