Climate during the early Holocene was highly variable due to the complex interplay of external and internal forcing mechanisms. The relative importance for them on the Asian monsoon (AM) evolution yet remains to be resolved. Here we present two-to six-yr-resolution oxygen isotope (δ18O) records of five stalagmites, four of which are annually-laminated, from Qingtian Cave, central China, revealing detailed AM variability between 10.9 and 6.1kaBP. Over the contemporaneous periods, the δ18O records agree well with each other at multi-decadal to centennial timescales. When pieced together with the previously published isotopic data from the same cave, the final δ18O record reveals detailed AM variability from the last deglaciation to the mid-Holocene, consistent with other cave records. The most striking feature of the δ18O record is the recurrence of centennial-scale oscillations, especially during the annually-counted period (8.8-6.1kaBP). Cross-wavelet analyses between the δ18O record and solar proxies show strong coherence at 200-yr cycle, suggesting that solar output was actively involved as a primary contributor. The AM depression at 8.2kaBP is indistinguishable in amplitude and pattern from a series of weak AM events after 8kaBP. We speculate that these centennial-scale AM changes might be regulated by the positive feedbacks of oceanic/atmospheric interactions to the solar activity under the condition of the retreat of continental ice-sheets.
Bibliographical noteFunding Information:
We are grateful to Dr. C. Spötl for his generous technical comments on an early version of this manuscript. Thanks are also given to an anonymous reviewer for his/her critical and instructive comments. This work was supported by grants from the National Nature Science Foundation of China (No. 41172148 , 41130210 , 41230524 ), NBRP (No. 2013CB955902 ), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) , Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application , and the Open fund for Jiangsu Key Laboratory of Environmental Change & Ecological Construction .
© 2015 Elsevier Ltd.
- Annually-laminated stalagmites
- Cyclic Asian monsoon changes
- Early mid-Holocene
- Qingtian Cave