DO3事件的湖北神农架高分辨率年纹层石笋记录  

THE DO3 EVENT IN ASIAN MONSOON CLIMATES EVIDENCED BY AN ANNUALLY LAMINATED STALAGMITE FROM QINGTIAN CAVE, MT. SHENNONGJIA

作　　者：王权[1,2,3] 汪永进[1,2,3] 刘殿兵[1,2,3] 赵侃[1,2,3] 邵庆丰[1,2,3] 程海[4] 黄伟[1,2,3] 

机构地区：[1]南京师范大学地理科学学院,虚拟地理环境教育部重点实验室,南京210023 [2]江苏省地理环境演化国家重点实验室培育建设点,南京210023 [3]江苏省地理信息资源开发与利用协同创新中心,南京210023 [4]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108-117,共10页Quaternary Sciences

基　　金：国家自然科学基金项目（批准号：41130210）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 感谢南京师范大学地理科学学院杨少华、邓少林硕士在采集稳定同位素样品给予的帮助;感谢匿名审稿专家和编辑部老师给予的建设性修改意见.

摘　　要：基于湖北神农架青天洞一支年纹层石笋（编号：QT15）高分辨 δ^18O序列，重建了29.4-27.4ka B.P.亚洲夏季风演化历史。QT15石笋 δ^18O在约27.9ka B.P.和28.7ka B.P.显著偏负，指示亚洲夏季风增强事件，分别对应于格陵兰冰芯记录的DO3事件和DO4事件。基于年层和高分辨率 δ^18O记录分析，石笋QT15记录的DO3事件具有3个阶段演化过程：第一阶段（28.04-28.01ka B.P.），亚洲夏季风在约30a内突然增强，对应于格陵兰地区该事件开始时的突然增温，揭示了北半球高、低纬突变气候事件的内在机制联系；第二阶段（28.01-27.91ka B.P.），亚洲夏季风呈现持续增强趋势，与格陵兰地区逐渐降温趋势相反，表明亚洲夏季风与格陵兰温度存在显著的区域差异；第三阶段（27.91-27.74ka B.P.），亚洲夏季风强度和格陵兰地区温度均显著降低，指示DO3事件结束。DO3事件确立后的季风持续缓慢增强与大西洋Cariaco海盆岩芯反射率记录基本一致，但明显不同于对应的格陵兰缓慢降温趋势。由此推断，在北半球突变事件诱发后，亚洲夏季风持续增强与赤道辐合带（ITCZ）北移以及越赤道气流增强高度耦合，与对应的格陵兰温度变化机制不同。The Dansgaard-Oeschger cycle has been extensively investigated in various geological archives, including ice cores, marine sediments and cave stalagmites. However, pattern and structure of the Dansgaard-Oeschger events appear to be quite different in different archives, suggesting different forcing mechanisms behind these regional climate changes. Here we further investigate character of DO3 in Asian monsoon climates by an annually laminated stalagmite from Central China. Stalagmite QT15 was collected from Qingtian Cave（31°20＇N, 110°22＇E, 1630m a.s.l.）, which is located at Mt. Shennongjia, Central China. Qingtian Cave is about 50m in length, and overlain by 60-100m Permian limestone. The relative humidity inside is close to 100%. This site is predominantly controlled by the Asian Monsoon（AM）, characterized by a distinct seasonal cycle of warm-wet summer and cold-dry winter. At the site, average annual temperature is about 7.4℃, with a maximum in July and a minimum in January. Mean annual precipitation near the cave is between 1500mm and 2000mm, about 80% of which falls during the rainy season when the Asian Summer Monsoon（ASM）prevails. Stalagmite QT15 is 285mm long, with a diameter from 70mm to 110mm. A hiatus at the depth of 68mm is visually inspected on the polished surface. Sample QT15 shows nearly straight horizontal layers perpendicular to the growth axis. These layers are composed of transparent and dark inclusion-rich calcite couplets. However, the couplets are not clear in the upper portion（above 68mm）. Therefore, we only focus on the lower portion（68mm to 285mm）in this study. Ten sub-samples were collected along the growth axis with 0.9-mm-diameter carbide dental burs for 230Th dating. The measurements were performed by multi-collected inductively coupled plasma mass spectrometry（ICP-MS） on a Fisher Thermo-Neptune spectrometer. All dates are in stratigraphic order with typical analytical errors（2σ）. For stable isotopic measurements, 435 sub-samples were drilled with 0

关 键 词：亚洲夏季风 DO3事件 青天洞 年纹层石笋 

分 类 号：P532[天文地球—古生物学与地层学] P736.44[天文地球—地质学]