Based on MC-ICP-MS U-series dating and stable O-isotope analysis results, a 4-5 years resolution monsoon record over the past 1000 years has been established for two stalagmites from Dongge Cave, Guizhou. The high resolution oxygen isotope record serves as a proxy for variations in rainfall of Asian southwest monsoon over the Yunnan-Guizhou Plateau. A close relation of the δ18O record with the Δ14C record from tree rings largely reflects impact of centennial-scale solar activity on the monsoon climate changes. The conspicuous decrease in the δ18O value at AD 1720 indicates an abrupt increase in monsoon rainfall, suggesting that an atmospheric-oceanic couple over the tropical Indian Ocean plays an important role in rapid increase of the Northern Hemisphere temperature over the last century.
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Acknowledgements This work was supported by the National Outstanding Youth Foundation of China (Grant No. 40225007) and the 973 Project (Grant No. 2004CB20204).
- Cave stalagmite
- Oxygen isotope
- Solar activity
- Southwest monsoon