小冰期十年际尺度亚洲季风变化的四川黑竹沟洞石笋记录  

DECADAL CLIMATE OSCILLATIONS DURING THE LITTLE ICE AGE OF STALAGMITE RECORD FROM HEIZHUGOU CAVE, SICHUAN

作　　者：蒋文静[1,2] 赵侃[1,2] 陈仕涛[1,2] 汪永进[1,2] 程海[3] 宁有丰[3] 

机构地区：[1]南京师范大学地理科学学院,南京210023 [2]江苏省地理信息资源开发与利用协同创新中心,南京210023 [3]西安交通大学全球环境变化研究院,西安710049

出　　处：《第四纪研究》2017年第1期118-129,共12页Quaternary Sciences

基　　金：国家自然科学基金项目（批准号：41572151和41572340）和江苏省高校优势学科建设工程项目（批准号：164320H116）共同资助.致谢 感谢审稿专家和编辑部老师建设性的修改意见,使论文得以完善.

摘　　要：基于四川省黑竹沟洞一支石笋（编号：EB1）高精度230Th年龄和氧同位素数据，建立小冰期时期（1375-1810A.D.）气候变化时间序列。该序列 δ^18O值变化范围为-10.37‰--8.58‰，敏感响应于区域气候变化过程。高分辨率 δ^18O变化序列能清晰地捕捉到10年际尺度振荡旋回。该石笋记录根据 δ^18O值变化可分为4个阶段：1375-1540A.D.和1680-1780A.D.时段， δ^18O值整体偏负，指示季风增强时期；1540-1680A.D.和1780-1810A.D.时段， δ^18O值整体偏正，处于弱季风阶段。与贵州董哥洞、甘肃万象洞和印度Jhumar洞石笋记录对比发现在小冰期时期 δ^18O变化特征具有一定的相似性，表明上述区域降水可能共同受控于印度季风水汽输送影响，反映了区域性夏季风经向环流及其降水变化特征。通过EB1石笋记录与北半球温度曲线的对比发现，两者在百年尺度上同相位变化，可能指示北高纬气候的控制作用。而该石笋与秘鲁东北部Cascayunga洞石笋记录的进一步对比结果显示亚洲季风与南半球季风记录呈反相位关系，证实了ITCZ位置的南北移动在半球间能量传递和交换过程中的重要作用。功率谱分析结果显示小冰期季风波动具有显著的25a和9a周期旋回，接近太阳黑子22a和11a周期频率，表明太阳活动变化可能是小冰期十年际尺度亚洲季风波动的重要驱动因素。The Heizhugou Cave（28°56＇02＂N, 103°05＇47＂E; 1400m a.s.l.）is located at Leshan, Sichuan Province, Southwest China. This study region lies in the eastern part of the Tibetan Plateau, southwest of Sichuan Basin. It is dominantly influenced by the Asian Summer Monsoon（ASM）whose mean annual rainfall ranges from 700 to 1200mm. The mean annual temperature in the cave is approximately 16℃ with relative humidity close to 100%. A stalagmite（EB1）was collected in the chamber with a total length of about 160mm. This sample is divided into two sections of 0-110mm and 110-160mm but there is no evidence of growth hiatus at the depth of 110mm according to lithology. Besides, the growth rate is stable throughout the entire stalagmite, as is supported by the 230Th dating results. We present a continuous high-resolution（ca.3a）record of ASM evolution from 1375A.D. to 1810A.D., roughly corresponding to the period of Little Ice Age（1300-1900A.D., LIA）. This paleoclimate time sequence was established by 9 precise 230Th dates and 160 stable oxygen isotope ratios（ δ^18O）. The dating measurements were conducted by multi-collector inductively coupled plasma spectrometer（MC-ICP-MS）at Institute of Global Environmental Change, Xi＇an Jiaotong University, China with error of ±2σ and δ^18O data were run at the Isotope Laboratory of Nanjing Normal University with Finnigan MAT-253 mass spectrometer fitted with a Kiel Carbonate Device accompanied by a standard deviation error of 0.06‰. The δ^18O values of the stalagmite（EB1）vary from -10.37‰ to -8.58‰ and its maximum amplitude is close to 2‰, illustrating sensitive response to regional climate change. The average δ^18O values during the periods of 1540-1680A.D. and 1780-1810A. D.is negative, implying relatively stronger ASM. And the average δ^18O values during the periods of 1375-1540A.D. and 1680-1780A.D. is positive, implying relatively weaker ASM. The general trend of δ^18O record from stalagmite EB1 is temporally consistent with

关 键 词：四川石笋 氧同位素 小冰期 亚洲季风 

分 类 号：P597.1[天文地球—地球化学] P532[天文地球—地质学]