川东北石笋记录的334～320ka夏季风变化与影响机制

HIGH-RESOLUTION PALEOCLIMATIC RECORDS OF MIS9 IN NORTHEASTERN SICHUAN,CENTRAL CHINA

间冰期气候是古气候研究中重点关注的内容之一。通过对川东北宋家洞石笋SJ5-6高精度^(230)Th定年和高分辨率氧同位素分析,重建了该地区334~320ka(MIS9)时期高分辨率夏季风气候变化历史。结果发现,SJ5-6记录的夏季风变化趋势总体上与亚洲季风区其他石笋记录相似,也与南极冰芯记录的温度变化基本一致,反映了在MIS9间冰期南半球高纬度地区温度变化可能对川东北地区的夏季风气候变化产生了重要影响。

Interglacial climate is one of the major concerns in paleoclimate investigations. The stable oxygen isotope of a stalagmite （SJ5-6） from the Songjia Cave in northeastern Sichuan, central China, which is pre- cisely dated with 230Th dating method, show prominent paleoenvironmental changes during the MIS （ma- rine oxygen isotope stage） 9. The stalagmite of SJ5-6 developed from 334 ka to 320 ka, a part of MIS9. The variations in δ18O of the stalagmite are interpreted as the responses to the millennial-scale fluctuations of the Asian summer monsoon intensity during 334- 320 ka. The δ18O record studied is roughly parallel with the other speleothem δ18O records recovered from the Asian summer monsoon region. In particular, there is a high similarity of temperature pattern between the stalagmite SJ5-6 and the Antarctic ice core. This suggests that temperature changes over the Antarctica may play an important role in the evolution of the Asian summer monsoon during the past interglacial.