A high-resolution stalagmite record from Luoshui Cave, Central China over the past 23.5 kyr

Abstract

A continuous high-resolution record from a precisely-dated stalagmite spanning the last precessional cycle provides new insight into the dynamics of climate change from orbital to centennial scales. A 600-mm length stalagmite (LS46) collected from the Luoshui Cave, Hubei Province, Central China, was well-dated (a total of 24 230Th dates) and high-resolved sampled for oxygen and carbon stable isotopic measurements (2047 subsamples in total). The stalagmite LS46 δ18O is consistent with other published stalagmite δ18O time series in monsoonal China, and closely tracks changes in the Northern Hemisphere summer insolation (NHSI) on July 21st throughout the past 23.5 kyr. Besides, the stalagmite LS46 δ18O shows significant correlations with the reconstructed Dali lake-level history and tree-ring δ18O records in the marginal monsoon regions. On this basis, we interpret that the stalagmite LS46 δ18O reflects the large-scale monsoon circulation with a superimposed local climate signal that might be related to effective humidity. Furthermore, the stalagmite LS46 δ18O exhibited four long-lasting extremely weak monsoon events since 7 kyr B.P.. These four weak monsoon events corresponded well with the tree-ring record in the northwestern fringe of the East Asian summer monsoon (EASM) region. Notably, the good correspondence between the stalagmite record and the tree-ring record also provides a good chronological support for our assessment of the climate and cultural evolution during the middle-late Holocene transition, the medieval warm period (MWP) and Little Ice Age (LIA). During the early-middle Holocene, the detrended δ18O profile revealed 10 multi-centennial monsoon cycles with a duration of nearly 500 yr and the amplitude of ∼0.8‰. The wavelet analysis further discloses that the EASM has nearly 500 yr and 200 yr periodic oscillations in the early-middle Holocene, research indicated that the solar activity and the North Atlantic Oscillation (NAO)/North Atlantic Deep Water (NADW) jointly drive the dominant nearly 500 yr cycle of the Asian monsoon.