Long-chain alkenone-inferred temperatures from the last deglaciation to the early Holocene recorded by annually laminated sediments of the maar lake Sihailongwan, northeastern China

Abstract

Abrupt temperature changes during the last deglaciation are well recognized in Greenland ice cores and in deep-sea sediment records. On the continent of monsoonal Asia, however, only a few terrestrial temperature reconstructions extend to the Younger Dryas (YD). This hampers the understanding of how the Asian monsoon system responded to large-scale boundary changes in ice-sheet dynamics and reorganizations of atmospheric–oceanic circulation between the last deglaciation and the Holocene. Here, we report an alkenone-inferred temperature record from varved sediments of the maar lake Sihailongwan, northeastern China. Alkenone provides temperatures that represent the water temperature during the growing season when the lake is ice-free. Annually laminated sediments provide a reliable time control. Reconstructed temperatures reveal a distinctive pattern of variations during the last deglaciation: a temperature increase of 6°C at the onset of the Bølling–Allerød, two cold intervals (during the Older Dryas and the intra-Allerød cold period), a relatively minor temperature decrease of 1–3°C during the YD, and a rapid temperature increase of 4–5°C at the early Holocene. The reconstructed temperature records from Lake Sihailongwan and adjacent regions indicate that summer (or growing season) temperature changes were smaller than is evident in Greenland ice core records that are weighted toward winter.