重庆地区末次冰期气候变化的石笋记录研究

Study on Climate Change Based on Stalagmite from Chongqing Cave During the Last Glaciation

对采自重庆金佛山梁天湾洞穴的1根长达295mm的石笋进行了高精度的TIMS—U系定年和碳氧同位素测试分析，建立了末次冰期晚期（31．90～15．21kaB．P．）长江中游较高分辨率（平均为280a／mm）的古气候变化序列。从石笋的氧同位素曲线中明显地检出Heinrich事件，并且氧同位素曲线与南京葫芦洞和贵州董歌洞的石笋记录有着良好的对比关系。但明显的差别是，重庆地区石笋的同位索记录表明，该地区末次冰期晚期古气候是受西南季风和东南季风双重影响的。

A relatively high-resolution paleoelimatic change sequences was established based on a mass-spectrometric uranium-series dated stalagmite from the Jinfu Mts. Caves of Chongqing region during the late period of Last Glaciation （31.90 ka - 15.21 ka B. P. ）. The stalagmite began to deposit at 31.90 ka B. P. and ended at about 15.21 ka B.P. without any obvious hiatus. The depositional ratio is about 1. 77 mm/100a in average. A high-resolution δ^18O records of the stalagmite demonstrates not only the existence of the abrupt climatic change, the Henrich events, but also bears a high similarity to the δ^18O-paleotemperature record of Nanjing Hulu and Guizhou Dongge caves, indicating the paleoelimate of Chongqing region, even at the middle reaches of the Yangtz River, was confined by both the influences of Indian summer monsoon and East Asia summer monsoon at the late period of the Last Glaciation.