由于深海氧同位素阶段5时期(Marine Isotope Stage 5,MIS 5)高分辨率的亚洲夏季风记录较少,限制了对该时期亚洲夏季风变化的认识。本文利用重庆金佛山羊口洞石笋的delta~(18)O记录,重建了MIS 5a/5b时期平均分辨率为38年的亚洲夏季风演变历史。发现该时段亚洲夏季风在千年一百年尺度上与北大西洋地区气候变化存在紧密联系。得益于误差小于0.4%的~(230)Th测年结果,本文标定了中国间冰阶(Chinese Interstadial, CIS)21的开始时间为84.60.3 ka BP,CIS 22的起止时间分别为91.20.3 ka BP和88.90.3 ka BP。此外,羊口洞石笋记录的CIS 21和CIS 22的变化模式与格陵兰记录不同,而与南极冰芯记录呈反相对应,可能表示在此阶段亚洲夏季风受到了南半球气候变化的影响。
英文摘要:
Due to the paucity of the high-resolution records of the Asian summer monsoon (ASM) during the marine isotope stage (MIS) 5,our understanding about the ASM in this period is limited. In this study, a 38 -yr resolution stalagmite oxygen isotope record from the Yangkou Cave, Chongqing, southwestern China, is used to reconstruct the detailed evolution of the ASM during the period of MIS 5a/5b. The Yangkou record exhibits a close correlation between the ASM and the climate of the North Atlantic at a centennial-millennial-scale. In terms of the precise ~(230) Th dating with error less than 0.4%,the onset and termination of Chinese Interstadial (CIS) 22 are constrained to 91.20.3 ka BP and 88.90.3 ka BP, respectively,and the beginning of the CIS 21 is defined at 84.60.3 ka BP. In addition, the evolution pattern of CIS 22 and CIS 21 recorded in the stalagmite from the Yangkou Cave is slightly different from those recorded in NGRIP, which is anti-phased with the trend of temperature change in the Antarctica. We speculate that the ASM during MIS 5a/5b may be affected by climate variation in the southern hemisphere.