Modern hydrology and late Holocene history of Lake Karakul, eastern Pamirs (Tajikistan): A reconnaissance study

Lake Karakul in the Pamirs (Tajikistan) is a deep brackish-water lake in a closed basin at almost 4000 m above sea level. Water samples from the catchment area and Lake Karakul, and a 104-cm sediment core from its shallow eastern sub-basin, were investigated and provide a first lake record from the region spanning the last 4200 cal yr BP. Multi-proxy analyses revealed the following: A relatively high meltwater inflow from glaciers, snow fields and frozen ground in the catchment as a result of relatively warm conditions was reconstructed for the period between 4200 and 3500 cal yr BP. The shift to colder climatic conditions around 3500 cal yr BP was probably abrupt: total organic carbon values displayed the most dramatic drop for the entire core within less than 40 years. In contrast, the subsequent re-establishment of warmer conditions occurred gradually over several centuries. A higher meltwater supply to the lake and warmer conditions were recorded since ca. 1900 cal yr BP with two slightly colder intervals between 1200 and 800 cal yr BP and between 400 and 100 cal yr BP. The abrupt shift to significantly colder and drier conditions around 3500 cal yr BP in the eastern Pamirs is seen also in records from the Aral Sea and the Guliya ice core from the western Tibetan Plateau. However, more palaeoclimate studies in this highly continental part of Central Asia are needed to assess the spatial and temporal patterns of the Holocene climate in the region. (C) 2010 Elsevier B.V. All rights reserved.