近千年来青藏高原东南缘印度夏季风降水变化的石笋记录  

India summer monsoon rainfall change over southeastern Tibetan Plateau during the last millennium recorded by laminal stalagmite

作　　者：江理渊 蔡炳贵 李苗发 王芳 刘宏[6] JIANG Liyuan;CAI Binggui;LI Miaofa;WANG Fang;LIU Hong(School of Geographical Sciences&School of Carbon Neutrality Future Technology,Fujian Normal University,Fuzhou 350117,Fujian;State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province,Fujian Normal University,Fuzhou 350117,Fujian;Institute of Geography,Fujian Normal University,Fuzhou 350117,Fujian;Key Laboratory of Cenozoic Geology and Environment,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029;Taishan Research Institute,Taishan University,Tai'an 271000,Shandong;International Joint Research Center for Karstology,Yunnan University,Kunming 650500,Yunnan)

机构地区：[1]福建师范大学地理科学学院、碳中和未来技术学院,福建福州350117 [2]福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福建福州350117 [3]福建师范大学地理研究所,福建福州350117 [4]中国科学院地质与地球物理研究所,北京100029 [5]泰山学院泰山研究院,山东泰安271000 [6]云南大学国际喀斯特联合研究中心,云南昆明650500

出　　处：《第四纪研究》2024年第6期1575-1589,共15页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:42072213和41661144021)资助。

摘　　要：基于云南西北部香格里拉赤土仙人洞一支长约120 mm的石笋(CTXRD1205),通过5个230Th年龄、400余个年纹层和237个稳定氧同位素数据,建立了近千年以来青藏高原东南缘印度夏季风降水演化序列。记录显示,近千年来δ^(18)O在波动中呈偏正-偏负-偏正的长期变化趋势,与印度东北部石笋δ^(18)O呈同向变化,而与印度中部石笋δ^(18)O呈反向变化,指示区域夏季风降水从逐渐减弱后增强,在小冰期后半段开始显著减弱的长期变化趋势;近200年来季风整体呈偏弱的态势,是公元1000年以来最干旱的时期,这一时期来自印度洋的水汽有所减少;在此基础上,近千年来青藏高原东南缘夏季风降水存在着几个多年代-百年尺度的偏强/偏弱时期,其中14世纪、15世纪初和18世纪的3次较为显著的干旱事件在中南半岛和南亚地区的记录均有不同程度的体现。谱分析和对比结果表明,近千年来研究区年代-百年尺度上的夏季风降水变化主要受太阳活动和太平洋年代际振荡(PDO)调控作用;但自然驱动背景下的中世纪气候异常期和小冰期与叠加了人类活动背景下的现代暖期,二者对研究区夏季风调控作用有所不同。在中世纪气候异常期和小冰期,区域季风降水偏强/偏弱对应于太阳活动极大期/极小期和PDO正相位/负相位,而在现代暖期,太阳活动影响减弱,区域季风降水偏强/偏弱对应于PDO负相位/正相位。The water vapor from the Indian Ocean has a significant impact on the dry;wet conditions in China and even East Asia.Here,we present a high-resolution oxygen isotope time series of stalagmite from Chituxianren cave in northwestern Yunnan,China to characterize regional Indian Summer Monsoon(ISM)monsoonal precipitation change over the past millennium.The Chituxianren cave(27°46'N,99°38'E,with an elevation of about 3494 m at the entrance)is located in Shangri-La,northwestern Yunnan Province,southeastern Tibetan Plateau.The mean annual temperature and precipitation in the area are 6.3℃and 650.8 mm,respectively.Influenced by the Indian Summer Monsoon,the rainy season(June to September)accounts for about 71%of the annual precipitation.The actively growing calcite stalagmite CTXRD1205 was collected from a corridor about 30 meters away from the entrance in the summer of 2012 A.D.The upper half,about 120 mm in length and 35~50 mm in diameter,is employed to build climate proxies in this study.The annually lamina with black carbon deposition can be clearly identified after halved and polished the sample and then thin section was made for lamina counting and thickness measurement(from the top to a depth of 60 mm).Total of 5230Th dating were performed on MC-ICP-MS.A total of 237 subsamples were drilled along the vertical growth axis for stable oxygen isotope measurement,using a Kiel-ⅣCarbonate Device linked to Finnigan Mat-253 gas isotope ratio mass spectrometer.Theδ^(18)O time series records the evolution of the Indian summer monsoon with an average resolution of ca.9 years from 952 A.D.to 2012 A.D.There are 409 laminae identified from the upper 60 mm of CTXRD1205.The annual laminae thickness ranges from 33.0μm to 366.8μm,with an average of 147μm.Theδ^(18)O values of CTXRD1205 varies from-10.72‰to-16.69‰,with an average of-14.31‰,and showing multi-decadal to centennial time scales change.The annual thickness sequence over the past 400 years has a similar variation trend with theδ^(18)O sequence,with larger

关 键 词：青藏高原东南缘 滇西北 石笋 稳定氧同位素 印度夏季风 近千年 

分 类 号：P532[天文地球—古生物学与地层学] P534.632[天文地球—地质学]