Millennial-scale changes in the Asian monsoon during the MIS12 period as recorded by a Chinese stalagmite

Marine Oxygen Isotope Stage 12 (MIS 12), the last glacial period before the Mid-Brunhes event (MBE), is considered the coldest glacial period during the past several glacial/interglacial cycles and is important because it can help better understand the cyclicity and mechanism of the millennial-scale variability of a glacial period. However, owing to the lack of precisely dated and high-temporal-resolution records, the millennial-scale variability during this period remains unclear. A 230Th/U dated stalagmite from Luoshui Cave, Hubei Province, Central China, was analyzed for stable oxygen isotopes (δ18O). An ∼120-yr-resolution δ18O profile is presented to clarify the Asian summer monsoon (ASM) history between 464 and 420.6 kyr BP (Before present, where present = 1950 CE), which corresponds to the interval from the MIS 12 to the early part of the MIS 11. The MIS 12 monsoon generally followed the insolation differences on June 21 between 30°N and 30°S and was interrupted by ten Chinese interstadial events (CISs). At least nine prominent weak monsoon intervals (WMIs) were identified during MIS 12 and displayed a strong coupling with the northern high-latitude climate and Antarctic temperature through the bipolar seesaw model, suggesting a substantial relationship with the bipolar region. This indicates that millennial-scale variability in the ASM region is an inherent feature of the MBE and has a global teleconnection. Additionally, in contrast to the EPICA DOME C3 (EDC 3) timescale, the new absolutely dated speleothem record confirms the Antarctic Ice Core Chronology 2012 (AICC 2012) at MIS 12, a period with a large difference between the two ice record geochronologies over the past 800 kyr.