CIS 24事件的精确定年及亚旋回特征：以黔北三星洞石笋为例  

PRECISE DATING OF THE CHINESE-INTERSTADIAL 24 EVENT AND ITS SUB-CYCLES INFERRED FROM A HIGH RESOLUTION STALAGMITE δ18O RECORD IN NORTHERN GUIZHOU PROVINCE

作　　者：王晓艳[1,2] 何尧启[3] 姜修洋[1,2] 

机构地区：[1]福建师范大学地理研究所,福州350007 [2]福建师范大学地理科学学院,湿润亚热带生态地理过程教育部重点实验室,福州350007 [3]贵州民族大学旅游与航空服务学院,贵阳550025

出　　处：《第四纪研究》2015年第6期1418-1424,共7页Quaternary Sciences

基　　金：国家自然科学基金项目（批准号：41372189）和福建省公益类研究所基本科研项目（批准号：2014R1034-2）共同资助

摘　　要：根据黔北三星洞一支石笋（SX15a）7个230Th年龄和194个氧同位素数据,获得了110.2～ 103.3ka B.P.时期分辨率约为35a的δ18O时间序列.该石笋δ18O记录了Chinese Interstadials （CIS） 24事件的详细变化过程.SX15a石笋δ18O值在CIS 24事件开始时（107.7±0.6ka）从-8.25‰迅速偏负至-10.0‰,而在事件结束时（105.4±0.5ka）δ18O值则相对缓慢的偏正,从-9.7‰偏正至-8.5‰,CIS 24持续时间为2.3±0.5ka.高分辨率的三星洞δ18O序列揭示出CIS 24事件内存在4个亚千年尺度的夏季风增强事件.与格陵兰冰芯记录的Greenland Interstadials（GIS） 24事件对比可以看出,无论是在千年尺度还是百年尺度,三星洞石笋δ18O记录的季风气候与北高纬气候都存在紧密耦合关系,说明在冰量相对较小的边界条件下,东亚夏季风强弱仍与北高纬气候变化密切相关.Recently published North GRIP ice core records precisely described the abrupt changes of the Greenland temperature during Marine Isotopic Stage （MIS） 5 with three stages of sub-millennial scale events. However, it remains uncertain about the behaviors of the Chinese Interstadials （CIS） events sub-cycle variability and its the linkages with the northern high latitudes during this period. Sanxing Cave （27°22＇N, 107°11＇E; 720m a.s.1.） with a depth of ca.2km, is located in Tiechang Town, ca.70km southeast of Zunyi City, Guizhou Province, Southwest China. This region is strongly influenced by the Asian summer monsoon （ASM） with the peak monsoon precipitation in the summer （JJA） and the dry season in winter （DJF）. The annual average precipitation is ca. 1000mm and the mean temperature is 13.5℃. Cave temperature is 12.8℃ （ in April 2010）. This region is dominated by the subtropical broadleaf evergreen and deciduous mixed forests. From 7 high-precision 230Th ages and 194 oxygen isotope data points, a stalagmite from Sanxing Cave （SX15a） in northern Guizhou Province reveals the precipitation history of the ASM from 110.2ka B.P. to 103.3ka B.P. （relative to 1950A.D.）. The stalagmite sample length is ca.650mm, diameter is ca.65mm. Each sub- sample for δ18O measurements was milled using dental burrs in size of 0.5mm along the length of the stalagmite profiles parallel to the central growth axis. Spacing between samples was 2mm. A total of 194 powdered sub-samples for δ18O measurements were performed by a Finnigan MAT-253 mass spectrometer connected to an on-line automated preparation system （Gasbench 11 ）. Results were reported relative to the Pee Dee Belemnite （PDB） standard and standardization was accomplished using NBS-19. Seven sub-samples were dated with the U-series methods. U-Th isotopic compositions and concentrations were determined on a Thermo-Fisher NEPTUNE multi-collection inductively coupled plasma mass spectrometer （MC-ICP-MS）. All date errors given

关 键 词：黔北 三星洞 石笋氧同位素 CIS 24事件 亚旋回 

分 类 号：P532[天文地球—古生物学与地层学] P597.2[天文地球—地质学]