A new speleothem record of the penultimate deglacial: Insights into spatial variability and centennial-scale instabilities of East Asian monsoon

Abstract

We present a highly resolved oxygen isotope (δ18O) record of the penultimate glacial-interglacial transition from a 230Th-dated stalagmite (SD1) from the Shangxiaofeng Cave in north-eastern China. Our δ18O record reveals two prominent features. First, the SD1 δ18O record documents a brief increase of δ18O between 128.5 and 128.1 ka BP. Though this event has been identified in several marine records, our radiogenic dated record precisely constraints the timing and duration of the climate deterioration suggesting that this YD-like event is likely an intrinsic feature of climate change during the ice age terminations. Additionally, the δ18O magnitude of the glacial-interglacial change (∼0.7‰) is significantly smaller compared to the δ18O records from inland and relatively high elevation caves (Dongge, Sanbao and Yangkou caves) (1.4–2.4‰) but comparable to the Hulu Cave at low elevation and proximal to the shallow Bohai and Yellow seas (Kelly et al., 2006; Cheng et al., 2006; Wang et al., 2008; Cheng et al., 2009; Li et al., 2014). Assuming that the cave δ18O records mainly reflect precipitation isotope composition changes, the glacial-interglacial speleothem δ18O difference between the various Chinese caves could be related to changes in atmospheric circulations, changing effect of altitude between the various caves and climate mean states, and large-scale changes in regional land-sea coverage due to sea level changes. The latter leads to disappearance and expansion of Bohai and Yellow seas during glacial and interglacial episodes, respectively, and likely affect the amount and isotope composition of precipitation. Taken together, our study highlights that hydroclimate imprints of the East Asian Monsoon changes during the penultimate glacial-interglacial cycle were spatially heterogeneous and centennial-scale monsoonal hydroclimate instabilities are likely inherent features of deglacial climate transition.