论文部分内容阅读
对采自川东北仙人洞的石笋XR025进行了高精度~(230)Th定年和高分辨率氧-碳同位素分析,重建了该地区33~28ka B.P.高分辨率夏季风气候变化历史。结果发现,XR025清晰地记录GIS4,GIS4.1和GIS5等温暖事件以及H3这一寒冷事件,这些事件的发生时间与格陵兰冰芯和我国其他石笋记录基本一致。但XR025记录的GIS4.1事件的强度明显比GIS4事件弱,这与格陵兰冰芯和葫芦洞石笋记录一致,但与我国其他一些石笋记录存在差异。在从H3向GIS4的转化中,XR025记录了夏季风逐渐增强的过程,这与格陵兰冰芯和我国其他石笋记录均存在明显差异,但与南极温度变化相似,可能受到了南极温度变化的影响。因此,南北半球高纬度地区温度变化可能在33~28ka B.P.对我国中部地区的夏季风气候变化产生了重要影响。
High-resolution ~ (230) Th dating and high-resolution oxygen-carbon isotope analysis of the stalagmite XR025 collected from Xianren Cave in northeastern Sichuan were carried out to reconstruct the climate change history of 33 ~ 28 ka B.P. high-resolution summer monsoon in this area. The results showed that XR025 clearly recorded the warm events such as GIS4, GIS4.1 and GIS5 as well as the cold events of H3, which occurred basically in line with the records of Greenland ice cores and other stalagmites in China. However, the intensity of GIS4.1 recorded by XR025 was obviously weaker than that of GIS4, which was consistent with the stalagmite records of ice cores and gourd holes in Greenland, but different from the records of some other stalagmites in China. During the transition from H3 to GIS4, XR025 recorded the gradual increase of summer monsoon, which is significantly different from that of Greenland ice core and other stalagmite records in China. However, similar to the changes in the Antarctic temperature, XR025 may be affected by the temperature changes in the Antarctic. Therefore, the temperature change in the high latitudes of the northern and southern hemispheres may be between 33 and 28 ka B.P. has an important impact on the summer monsoon climate change in central China.