摘要
位于青藏高原与黄土高原过渡带的甘肃武都万象洞石笋WXSM51和WXSM52提供了M IS 5(118~79kaB.P.)高分辨率的1δ8O记录。研究表明,万象洞石笋1δ8O值与夏季风强度呈负相关关系,与我国西南部的贵州董歌洞石笋1δ8O记录有良好的对应关系,并与高纬度的格陵兰NGR IP冰芯1δ8O记录和65°N太阳辐射强度有很好的一致性,说明万象洞石笋1δ8O记录了118~79kaB.P.期间亚洲季风强度的变化,同时也说明东亚季风强度的变化和全球气候变化同步,而且主要受控于北半球太阳辐射强度的变化。同时它与地中海碳酸盐记录有很好的相似性,和巴西石笋1δ8O记录在千年尺度上表现出相反的变化趋势,说明东亚季风区、地中海地区以及巴西季风区之间存在密切的联系,指示了南北半球气候在千年尺度上存在“跷跷板”(seesaw)现象。万象洞石笋1δ8O记录的M IS 5b与M IS 5 a突发性转换,与NGR IP冰芯1δ8O记录相似,而与神农架记录存在差异,说明万象洞地区对亚洲季风强度的响应更为敏感。
Speleothem, which is suited for precise U-series dating and contains many climate proxies, is widely used in paleoclimate reconstruction. In China, it has been proved that speleothem δ18O is suitable for paleomonsoon reconstruction in the south and east regions. But in the northwest region few studies have been done. Here, we report high resolution δ18O records of MIS 5 （from 118kaB. P. to 79kaB. P. ） from two stalagmites （WXSM51 and WXSM52） collected form the Wanxiang Cave, Gansu Province （33°19＇N, 105°00＇E）.
The Wanxiang Cave is located at the transition zone between the Qinghai-Tibetan Plateau and the Loess Plateau. The location is close to the northern limit of the summer monsoon. The results indicate that δ18O of stalagmite at this site is inversely related to the East Asian summer monsoon intensity. δ18O of the Wanxiang Cave closely resembles the D3 record from the Dongge Cave, and also agrees well with the NGRIP record and the 65°N summer isolation curve. These indicate that δ18O of the Wanxiang Cave is a valid and robust proxy for paleomonsoon intensity analysis. These also suggest that the East Asian monsoon varies in step with global climate change and is largely controlled by solar variations in the Northern Hemisphere.
The Wanxiang record presents similarity to the Mediterranean speleothem records, and presents an inverse pattern compared with the Brazilian stalagmite BT2 record on the millennial timescales. These indicate that there are climate links among the East Asian monsoon, the Mediterranean and the Brazil summer monsoon regions, and further prove that the north-south climate seesaw did exist.
It should be pointed out that the pattern of the transition from MIS 5b to MIS 5a recorded in the Wanxiang records differs from that in the Shennongjia stalagmite records. This difference, which does not seem to be caused by sampling resolution difference, may indicate that δ18O of the precipitation in the Wanxiang Cave region is more sensitive to changes in monsoon inten
出处
《第四纪研究》
CAS
CSCD
北大核心
2006年第6期985-990,共6页
Quaternary Sciences
基金
国家自然科学基金项目(批准号:40471137)
国家自然科学基金人才项目创新研究群体科学基金项目(批准号:40421101)
教育部博士点基金项目资助
关键词
洞穴石笋
氧同位素组成
亚洲季风
MIS5
甘肃武都万象洞
黄土高原西缘
Gansu Province, stalagmite, stable oxygen isotopic composition, Asian monsoon, MIS 5, Wanxiang Cave, Western Loess Plateau
