The Last Interglacial Climate Variability in Northern China

Speleothem oxygen isotope (δ18O) records can reconstruct high-resolution and absolutely dated climate history, in particular, the variability of monsoon precipitation that is associated with the changes in atmospheric circulation and, in turn, the δ18O of precipitation. In the East Asian monsoon domain, although speleothem records have been established in southeastern China over the last decade, including several records covering the last interglacial period (MIS 5e), similar records are virtually absent in northern China. This hampers our understanding of the mechanism of the East Asian monsoon changes, because the northern China δ18O record is, as recently shown by modeling work, more sensitive to changes in summer monsoon precipitation than that from southeastern China. Here we provide a high-resolution and absolutely dated speleothem δ18O record between ~129 and 119 ka BP from Kulishu cave, Beijing, northern China. It shows an abrupt onset of MIS 5e at 129.4×0.7 ka BP, similar within dating uncertainty to the Dongge, Hulu, and Sanbao records from southeastern China. However, the end of MIS 5e is rather gradual in comparison to the southern China counterparts. While overall MIS5e monsoon climate appears to be rather stable on orbital timescales, broadly following northern hemisphere summer insolation, millennial/centennial-scale events punctuate the Kulishu record. Spectral analysis reveals a significant quasi-1500 year periodicity, comparable to the Bond cycle, first observed in the North Atlantic during the Holocene, and more recently in interglacial East Asian monsoon cave records. As such, events with a ~1500 year pacing appear to be a persistent characteristic of the East Asian monsoon for good portions of the past two glacial-interglacial periods. Changes in solar output would be one possibility for the trigger; changes in ocean circulation with a ~1500-year time constant would be another. Comparison with Hulu(MSX, Cheng et al., 2006)-Dongge(D3, D4, Kelly et al., 2006)-Sanbao(SB23, SB25, Wang et al., 2008) complex.