末次冰盛期东亚夏季风变化的重庆石笋记录

基于重庆小山岩洞XSY1石笋的5个²³⁰Th年龄和582个氧同位素数据，重建了23134~19345 a B.P.期间分辨率约6.5 a的东亚夏季风变化历史。此石笋δ¹⁸O记录的长期趋势逐渐负偏，在其上叠加了一系列千年-百年尺度季风振荡，呈现为4谷3峰的结构形态。重庆XSY1和南京MSD石笋δ¹⁸O记录在数百年尺度的反相关系表明冰盛期时东亚大陆东部水汽并非来自印度洋。与北高纬记录对比显示东亚季风的增强与减弱基本对应格陵兰温度的升高与降低时期，暗示在冰量最大时期东亚季风与北高纬气候仍密切联系。
此外，XSY1的δ¹⁸O与冰芯¹⁰Be通量亦存在明显的对应关系，表明太阳活动对东亚季风的调控作用受冰量边界条件影响较小。功率谱分析结果显示出1011 a、722 a、460 a、337 a和163 a的周期，与太阳活动周期相近，进一步确认太阳活动对东亚季风的驱动作用。石笋XSY1与澳大利亚石笋MC-S2 δ¹⁸O记录在千年尺度呈反相位变化，表明冰盛期时东亚季风与全球其他气候系统的动力联系。

Variability of the East Asian summer monsoon during the Last Glacier Maximum recorded by a stalagmite oxygen isotope record in Chongqing,Southwestern China

A highly resolved and precisely dated record characterizes in detail the East Asian Summer Monsoon (EASM) during the Last Glacial Maximum (LGM). Here we report a stalagmite (no. XSY1) δ18O record from Xiaoshanyan Cave (29°42'N, 108°22'E; 456 m above sea level). This cave is located in Shizhu Tujia Autonomous County, Chongqing, Southwestern China. The area is climatically dominated by the EASM, featured by warm and wet summer, as well as cold and dry winter. The annual precipitation is more than 1110 mm in the region, most of which falls during the summer seasons.
Vegetation above Xiaoshanyan Cave is dense and is mostly composed of deciduous plants. The temperature and relative humidity are 17.4℃ and 100% inside the cave, respectively. The stalagmite XSY1 is 832 mm in length. When halved along its growth axis and polished, the sample becomes ivory in the upper section of 0~600 mm and fuscous in the lower part of 600~823 mm.