A Lateglacial and Holocene lake record from the Nianbaoyeze Mountains and inferences of lake, glacier and climate evolution on the eastern Tibetan Plateau

Abstract

Our 12.81m long record from Lake Ximencuo provides insight into the Lateglacial and Holocene evolution of the lake and the Nianbaoyeze glacier in its catchment, and the regional climate history since ∼19kyr. Lake Ximencuo was a permanent deep lake throughout its history. In contrast to numerous lakes on the Tibetan Plateau which experienced shallow lake levels or even desiccation during the Lateglacial, Lake Ximencuo was fed by large quantities of meltwater in the Lateglacial. The existence of glaciated upper catchment areas is apparently a prerequisite for lakes on the Tibetan Plateau which maintained relatively high water levels during the generally cold and dry periods following the global LGM (∼21kyr). A minor re-advance of the Nianbaoyeze glacier was recorded coeval with the Greenland Stadial 2a (∼16.4 and 14.5kyr), followed by rapid warming apparently synchronous with the Greenland Interstadial 1. Warmest conditions were recorded at Lake Ximencuo during the early Holocene which was punctured by a remarkable pulse of climate deterioration around 8.3kyr. This spell represents probably the 8.2kyr event of the North Atlantic region, suggesting that it had a significant impact on the Tibetan Plateau. Colder conditions of longer duration occurred from 4.7 to 3.7kyr, apparently in phase with numerous records signalling colder and drier conditions on the Tibetan Plateau. Two minor spells of colder conditions and probably catchment erosion were recorded in the late Holocene between 2.0 and 1.4kyr and between 0.5 and 0.1kyr with the latter representing the Little Ice Age. It is unclear, whether human activities may have accelerated or even solely triggered the late Holocene erosion events.