Abstract: Background, aim, and scop e With global warming, climatic extremes such as flood, drought and heat wave are becoming increasingly serious and exert more and more threats to human society. Investigations of past climatic extremes help us to understand the variations and controlling mechanisms and to contribute to prediction of these events. In this paper, a drought event which happened ~600 a ago in central China was reported to be recorded by a stalagmite (SI2) collected from NE Sichuan, and its evolution and controlling mechanisms were investigated. Materials and methods The stalagmite SI2 was collected from Shizi Cave (32°24′N, 107°10′E). U-230Th dates and 210Pb dating results indicate that SI2 developed during the last ~2100 years. The stable oxygen isotope (δ18O) of SI2 was determined with a Thermo-Fisher MAT 253 mass spectrometer with analytical errors better than 0.1 ‰. Results The SI2 δ18O record varied from -7.42 ‰ to -9.27 ‰ with an average of -8.67 ‰. A general decreasing trend was observed in the δ18O record prior to AD 200, followed by an apparent and long-lasting increasing trend until AD 1400 when the heaviest δ18O ratio of the whole record, -7.42 ‰ occurred. From AD 1400 to ~AD 1800, an overall negative shift was displayed with the lightest value of the whole record, -9.27 ‰ appeared at the end of this stage. The SI2 δ18O record showed a gradual increasing trend again during the last 200 years. The SI2 δ18O record indicated a drought event happened ~600 a ago, which was supported by the growth of stalagmite SI2. Calcite precipitation in SI2 was relatively more concentrated on the growth center when the event happened, suggesting lower dripping rates under a relatively dryer climate. The SI2 δ18O record suggested that the drought event was episodic, consisting of three dry episodes. Discussion This drought event was also recorded by other stalagmites in central China as well as historical documents. However, changes in hydroclimate in South China did not illustrate an apparent manifestation of this event. The spatial distribution of this event in monsoonal China suggested a possible origin from sea surface temperature in the tropical Pacific Ocean which might be in an El Niño-analogue state. However, this explanation was in contradiction with the recent work of Tan et al. (2019) and more investigations were warranted. Conclusions The δ18O ratio and growth of stalagmite SI2 recorded a drought event happened ~600 a ago in NE Sichuan in central China. This event consisted of three dry episodes. Recommendations and perspectives The spatial distribution of this event in monsoonal China suggested a possible tropical origin but further investigations were warranted in future.
Keywords: stalagmite; stable oxygen isotope; calcite precipitation; drought event; El Niño; central China