A tentative discussion on a heavy precipitation event recorded by stalagmites from Qixing Cave, Guizhou Province

In the background of global warming and higher frequency of extreme events, the study and investigation of the mechanism of extreme events that are likely to happen at present and in the future constitute a realistic and urgent work. Using geological records to reconstruct the past extreme events is an important method for detecting the extreme events. In this study, choosing Qixing Cave (25°59'N, 107°16'E, 978 m a.s.l.) in Guizhou Province as the study object, the authors investigated two calcite-aragonite stalagmites with similar depositional characteristics, and found that the same tawny laminas deposit in the top part of the two stalagmites may record the same heavy precipitation event. Some conclusions have been reached: (1) The tawny laminas recorded by stalagmites QX1 and QX6 have the same depositional characteristics, formed by clay carried by heavy precipitation. (2) The formation time of the two tawny laminas is the same within error, i.e., at AD (1868±1). (3) Climatic background of this heavy precipitation event was as follows: long time drought caused the reduction of vegetation covers and soil moisture, whereas there existed wet rainy season in 1869, and the clay carried by heavy precipitation was deposited on the surface of stalagmite to from lamina. The results obtained by the authors have opened a new train of theought for extreme precipitation research in East Asian monsoon area.