中全新世7～6ka东亚季风气候的高分辨率石笋记录  

High Resolution Stalagmite Records of East Asian Monsoon from 7 to 6 ka B.P.in Mid-Holocene

作　　者：李明霞[1] 汪永进[1] 邱庆伦[1] 

机构地区：[1]南京师范大学地理科学学院,江苏南京210097

出　　处：《地理科学》2007年第4期519-524,共6页Scientia Geographica Sinica

基　　金：国家杰出青年基金项目(批准号:40225007)资助

摘　　要：基于神农架青天洞石笋两个230Th年龄、582条纹层计数和183个氧同位素数据,重建了7～6 ka B.P.期间平均3年分辨率的1δ8O变化序列。持续约580年振幅达1.8‰的δ18O在平均值-9.66‰上下波动,指示了东亚季风降水强度的长期演化趋势和高频振荡信息,大致划分为4个百年尺度旋回。青天洞与阿曼石笋δ18O记录的对比表明,东亚季风和印度季风在百年或更短时间尺度上同相位变化,可能反映了两地季风气候受统一的印度洋/太平洋大尺度水汽循环控制。功率谱分析揭示出163、81、16和11年的周期,大致与树轮Δ14C百年至数十年尺度太阳活动变化周期相同。The Asian monsoon system, composed of the Indian and East Asian mosoon subsystems, is a dynamic component of the modern and paleoclimate system. Studies of different influence extent of solar radiation and coupled atmosphere-ocean system to Asian monsoon subsystems still remain complex. Some stuidies indicated the inverse phase variations between the Indian and East Asian mosoon, which is different to most of monsoon proxies results. Understanding the interactions among them and their sensitivity to internal feedback mechanisms requires high resolution proxies of monsoon climate. Qingtian Cave （110°22＇E, 31°30＇N, 1 630m above sea level ） is located almost at 10 km NW apart Muyu Town, Shengnongjia Natural Reserve, Hubei Province. Here, most of peaks are higher than 1500 m and generally become lower from SW to NE. Mean annual precipitation and temperature are 1 500-2 000mm at 1 500-2 000 m above sea level and 15.5℃ in the cave （measured in SOp. 2004）. Two samples for ICP-MS dating were conducted in the Isotope Laboratory of Geology and Geophysics Department, Minnesota University, USA. The reported error is in 2σ. A total of 183 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 Isotope Laboratory of College of Geography Science, Nanjing Normal University. Reference standards have been used to ensure a precision better than 0.06‰ and results were reported to PDB standard. A 3-year-resolution stalagmite oxygen-isotope record from Qingtian Cave has been established based on ^230Th dates and results of annual band-counting. The variation of oxygen isotope ratios with time, with amplitude as large as 1.8%0 in δ^18O , reflects changes in the amount of monsoon precipitation for the period from 6.7 to 6.1 ka B. P. This high temporal resolution δ^18O series enables us to reconstruct decadalcentennial scale variation of East Asian monsoon intensity persisting about 580 yea

关 键 词：神农架石笋 中全新世 年际分辨率 太阳活动 

分 类 号：P467[天文地球—大气科学及气象学]