NOAA/WDS Paleoclimatology - Liu-li Cave, China Speleothem d18O, d13C and Sr/Ca Data Over the Past 6,700 years

Speleothem records from NE Asia are essential to understand the spatial patterns of the Asian Summer Monsoon (ASM) variability. In this paper, we present a new high-resolution and chronologically well-resolved speleothem record from Liu-li (LL) cave, NE China, through d18O, d13C and Sr/Ca ratio characterizing a dynamic ASM history over the past 6680 years. The LL d18O record shows a long-term trend to higher values, following the North Hemisphere summer insolation (NHSI), with the exception of the last 2 kyr characterized by a negative d18O excursion. The ‘2-kyr shift’ is evident in NE Asia over the past 2 kyr, originally inferred from the speleothem d18O negative excursion in South China, as well as in many other proxy records from East China, but it merely manifests a flat trend in most of the western East Asian Summer Monsoon (EASM) and Indian Summer Monsoon (ISM) regions, rather than a negative excursion. On multi-centennial to millennial timescales, the intensification of the Tsushima Warm Current (TWC) can amplify rainfall on both sides of the Japan Sea. A close comparison between the monsoon reconstruction and the cultural changes in NE Asia suggests contemporary climatic and cultural regime-shifts, implying an important role of the ASM weakening in the collapse of Neolithic and Early Bronze cultures in this region.