倒数第二次冰期晚期东亚季风气候演变的石笋δ^(18)O记录  

EAST ASIAN MONSOON CLIMATE DURING THE LATE PENULTIMATE GLACIATION BASED ON STALAGMITE RECORDS

作　　者：任晓辉[1] 陈仕涛[2] 明艳芳[3] 汪永进[2] 

机构地区：[1]内蒙赤峰学院环境与资源管理系,赤峰024000 [2]南京师范大学地理科学学院江苏省环境演变与生态建设重点实验室,南京210097 [3]山东科技大学地理科学学院,青岛266510

出　　处：《海洋地质与第四纪地质》2007年第1期47-52,共6页Marine Geology & Quaternary Geology

基　　金：国家杰出青年科学基金(40225007)

摘　　要：基于南京洞穴2支石笋的11个230Th年龄、658个氧碳同位素分析数据,建立了倒数第二次冰期晚期(155-128 kaBP)东亚季风高分辨率的气候演化序列。在岁差尺度上,石笋δ18O记录与65°N夏季太阳辐射量曲线变化基本一致,说明北纬夏季太阳辐射对该地区气候演变起宏观调控作用。石笋δ18O变化曲线千年尺度上显示了8个明显的峰谷变化,δ18O值平均变幅约为1.5‰,平均频率在2 ka左右,十分类似于末次冰期东亚季风Dans-gaard-Oeschger旋回,说明东亚季风气候在末次冰期的千年级不稳定波动也可能存在于更久远的冰期过程中,冰期气候的不稳定性很可能是第四纪冰盖、大尺度海洋/大气环流共同作用的结果。Two stalagmites are from Hulu cave, which is 1 600 m above sea level （ASL） in Naniing. 11 subsamples are dated by Finnigan MAT 262-RPQ at the Isotope Laboratory of Geology and Geophysics Department, Minnesota University, USA, and all ^230Th ages are in stratigraphic order. The results provided a high-resolution paleoclimate record for East Asian monsoon area during a time interval from 155 to 128 kaBP of the penultimate glaciation. In order to check reliability of the stalagmite δ^18O record, we compared δ^18O records of these two stalagmites, for both grew contemporaneously during a time interval from 154.5 to 133 kaBP. The general replication of δ^18O values of contemporaneous growth for 21.5 ka suggests fidelity of δ^18O values as a proxy of paleoclimates. There were eight remarkable apexes in our stalagmite δ^18O record, which show a mean shift of 1.5‰ in δ^18O lasting about 2ka, and a mean frequency of 2 ka. It bears a striking resemblance to D/O events during last glacial period in terms of structure and transition well expressed in the Hulu δ^18O records. It is therefore likely that the dramatic climate fluctuation during the last glaciation may have occurred pervasively in the early glaciation time in Asian monsoon climates. Climate instability of glacial period may be also related to changes in the ice-sheets and tropical oceanic/atmospheric circulation.

关 键 词：倒数第二次冰期晚期 东亚季风 石笋 南京 

分 类 号：P532[天文地球—古生物学与地层学]