神农架全新世东亚季风演化及其热带辐合带控制  

THE EAST ASIAN MONSOON CLIMATE CHANGES AT MT. SHENNONGJIA AND ITS RELATION TO SHIFT OF INTERTROPICAL CONVERGENCE ZONE DURING THE HOLOCENE

作　　者：董进国[1] 孔兴功[1] 汪永进[1] 

机构地区：[1]南京师范大学地理科学学院,南京210097

出　　处：《第四纪研究》2006年第5期827-834,共8页Quaternary Sciences

基　　金：国家杰出青年科学基金项目(批准号:40225007)资助

摘　　要：文章基于湖北神农架山宝洞3支石笋的13个^230Th年龄和505个氧同位素数据，建立了全新世8．45—0．46kaB．P．东亚季风降水序列，其长期演化趋势与33°N夏季太阳辐射能量变化曲线基本一致。神农架山宝洞与阿曼Qunf洞和贵州董哥洞的石笋高分辨率δ^18O记录整体相关（r分别为0．75和0．94），说明全新世东亚季风、印度季风系统的演化主要受控于同-驱动机制，即北半球夏季太阳辐射控制下赤道热带辐合带逐渐南移，导致亚洲季风降水持续减弱。功率谱分析表明：5ka以来山宝洞石笋记录具有显著的550a周期旋回，与树轮△^14C和北大西洋温盐环流周期基本一致。The Shanbao Cave（31°40′N, 110°26′E, 1902m above sea level） is located almost at the top of Yanziya, 40 km NW away from the Songbai Town, Shennongjia Natural Conservation, Hubei Province. Most of peaks in this area are higher than 1500m and generally become lower and lower from SW to NE. Mean annual precipitation and temperature are 1500 -2000mm at 1500 -2000m above sea level and 12. 1℃ at Songbai Town （930m above sea level）. Three stalagmites （ SB6, SB26, SB27 ） were obtained from different positions of the Shanbao Cave. They appear to be cylinders and are mostly composed of pure, compact calcite minerals, and stalagmite SB6, SB26 and SB27 are 90mm, 260mm and 150mm long, respectively. A high-resolution oxygen-isotope record from a thoriumuranium-dated stalagmite from the Shanbao Cave reflects variations of monsoon precipitation for the period from 8.5ka to 0. 5ka （ lka = 1000cal. aB. P. ）. Thirteen samples for ICP-MS dating were conducted at the Isotope Laboratory of Geology and Geophysics Department, Minnesota University, USA. The reported error is in ± 2σ. A total of 505 samples for δ^18O measurements have been analyzed with on-line automated carbonate preparation system （KIEL CARBONATE DEVICE） linked to Finnigan MAT-253 ratio mass spectrometer at the Isotope Laboratory of College of Geography Science, Nanjing Normal University. The long-term trend of the Shanbao Cave record correlates the summer insolation at 33°N latitude. As mentioned in many previous studies, heavier δ^18O values are associated with diminished monsoon precipitation, and vice versa. By comparing high-resolution δ^18O record of stalagmite from the Shanbao Cave （Hubei, China） with that from the Qunf Cave （Oman）, and the Dongge Cave （Guizhou, China）, we find out that the average value of stalagmite δ^18O decreases northward with an increase in latitude. Furthermore, the long-term trends from three stalagmite records agree each other well during the Holocene （the correlation coefficient is 0.74

关 键 词：全新世 石笋 东亚季风 神农架 

分 类 号：P534.632[天文地球—第四纪地质学]