Stable isotopic measurements on the upper 168 cm of stalagmite DG24 from southern China, which is annually-laminated above 74.8 cm (∼11.8 ka), reconstruct a history of detailed Asian summer monsoon (ASM) variability and soil processes between 14.8 and 10.3 ka. The climate sequence of Bølling-Younger Dryas (YD)-Preboreal events is evident in δ18O record. In the Preboreal, four-year-resolution and annually-counted δ18O record reveals that the ASM strengthening can be divided into three phases, with a prominent and persistent rise initiated at about 11.2 ± 0.3 ka, likely in response to interactions between ocean, atmosphere, and ice sheets. In contrast, the long-term δ18O depletion is absent in the δ13C and annual layer records, which characterize persistent centennial oscillations and likely represent relative humidity of the soil. At multi-decadal scale, prominent ASM failures are generally consistent with periods of δ13C enrichment and decreased layer thickness. When compared with solar proxies, centennial-scale δ13C changes match well with solar activity regardless of the observed disparity between ASM and solar records, and common cycles of 130 and 300 years are identified in both the atmospheric Δ14C and speleothem δ13C records. This implicates that during the Preboreal local soil humidity budget and CO2 production, indicated by the δ13C and annual layer records, is more sensitive to changes in solar output than the regional hydroclimate variability recorded by the δ18O signal.
Bibliographical noteFunding Information:
We are grateful to two anonymous reviewers for their critical and instructive comments. This work was jointly supported by grants of National Nature Science Foundation of China (No. 41672161 , 41172148 , 41130210 ), A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) ( 164320H116 ), Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application , and Key Laboratory of Virtual Geographic Environment (Nanjing Normal University).
© 2016 Elsevier Ltd and INQUA
- Annually-laminated stalagmite
- Asian monsoon
- Daoguan Cave
- Soil processes
- The Preboreal