翟秀敏^1,2,3,4,,
孔兴功^1,2,3,,,
张远海⁴,
张敬伟^1,2,3,
王权⁵,
邵庆丰^1,2,3,
张振球^1,2,3
1. 南京师范大学地理科学学院, 江苏, 南京 210023
2. 虚拟地理环境教育部重点实验室(南京师范大学), 江苏 南京 210023
3. 江苏省地理信息资源开发与利用协同创新中心, 江苏 南京 210023
4. 中国地质科学院岩溶地质研究所, 自然资源部/广西岩溶动力学重点实验室, 广西 桂林 541004
5. 重庆师范大学地理与旅游学院, 三峡库区地表过程与环境遥感重庆市重点实验室, 重庆 401331

基金项目: 国家自然科学基金面上项目（批准号：41672164）、国家自然科学基金重点国际合作项目（批准号：41420104002）和中国地质科学院岩溶地质研究所所长基金项目（批准号：2014005和2016011）共同资助


详细信息

作者简介: 翟秀敏, 女, 33岁, 博士研究生, 自然地理学专业, E-mail:karstmin@karst.ac.cn

通讯作者: 孔兴功, E-mail:kongxinggong@njnu.edu.cn

中图分类号: P597⁺.2;P532

收稿日期:2020-01-30
修回日期:2020-05-12
刊出日期:2020-07-30

Intensified East Asian summer monsoon during the interval of DO18: Recorded in a high resolution, absolute-dated stalagmite from Didonghe, Shaanxi, Central China

Zhai Xiumin^1,2,3,4,,
Kong Xinggong^1,2,3,,,
Zhang Yuanhai⁴,
Zhang Jingwei^1,2,3,
Wang Quan⁵,
Shao Qingfeng^1,2,3,
Zhang Zhenqiu^1,2,3
1. School of Geography, Nanjing Normal University, Nanjing 210023, Jiangsu
2. Key Laboratory of Virtual Geographic Environment(Nanjing Normal University), Ministry of Education, Nanjing 210023, Jiangsu
3. Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, Jiangsu
4. Key Laboratory of Karst Dynamics, Ministry of Natural Resources & Guangxi Zhuang Autonomous Region, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin 541004, Guangxi
5. Key Laboratory of Surface Process and Environment Remote Sensing in the Three Gorges Reservoir Area, School of Geography and Tourism, Chongqing Normal University, Chongqing 401331


More Information

Corresponding author: Kong Xinggong,E-mail:kongxinggong@njnu.edu.cn

MSC: P597⁺.2;P532

--> Received Date: 30 January 2020
Revised Date: 12 May 2020
Publish Date: 30 July 2020


摘要
摘要:千年尺度事件的结构特征和区域响应是理解和认识冰期气候变化及动力机制的关键。本文基于陕西汉中宁强县地洞河一支长417 mm石笋DDH1的11个U-Th年代和417个氧同位素（δ¹⁸O）数据，重建了末次冰期（64.8~33.2 ka B.P.）亚洲季风演化历史。石笋δ¹⁸O记录在64.7±0.2 ka B.P.和59.3±0.1 ka B.P.快速负偏，分别指示了DO18事件的开始和H6事件的结束。在DO18事件结束过程，石笋δ¹⁸O记录在64.0~60.4 ka B.P.持续正偏，振幅达2.9 ‰，反应季风逐渐减弱，但未出现明显转型阶段。其总体形态与大西洋Cariaco盆地岩芯反射率、南极冰芯的记录较为一致，但是不同于格陵兰冰芯的记录。因地洞河所处青藏高原、秦岭叠加影响的区域，纬度和地形的双重影响使得其石笋δ¹⁸O记录较其他地区偏负，振荡幅度更大。因地形阻挡了高纬信号，使得低纬甚至南半球的信号突现出来，ITCZ的移动、南半球温度和水汽潜热的释放作用在这一区域尤为显著。
关键词: 地洞河/
石笋/
DO18事件/
H6事件/
东亚夏季风/
氧同位素

Abstract:Shaanxi Didonghe is located at the southern slope of Qinling Mountains, and the climate here is mainly controlled by monsoon systems. The blocking of Qinling Mountains and Tibetan Plateau arises different contribution rate of high and low latitude influence, so it makes typical millennial scale events recorded in this region.
We collected a stalagmite about 417 mm long from Didonghe Cave (32°40'45″N, 106°32'25″E; 1262 m a.s.l.), Ningqiang County, southern region of Shaanxi Province. Mean annual precipitation here is 1100 mm and 70% precipitation falls in May to August. 11 subsamples were drilled with 0.9 mm dental burs along the central grow axis and dated with U-series method by ICP-MS on a Fisher Thermo-Neptune spectrometer at Nanjing Normal University Isotope Laboratory. 417 subsamples were drilled with 0.5 mm diameter carbide dental burs along the grow axis for stable isotope analysis. All this work was finished by Finnigan MAT 253 mass spectrometer at Nanjing Normal University Isotope Laboratory.
Based on the lamina chronology and 417 calcite δ¹⁸O datas for DDH1, a detail of ASM from 64.8 ka B.P. to 33.2 ka B.P. was reconstructed. The results indicated that the grow rate varies from 4.89 μm/a to 27.00 μm/a, the slowest grow stage is in 44.94~53.33 ka B.P. Three weak monsoon events H4, H5a and H6 were recorded. However the weak monsoon event H5 was not completely traced. During 64.7±0.2 ka B.P., the calcite δ¹⁸O values decreased rapidly about 2 ‰, indicating an abrupt strengthening in Asia summer monsoon, which is associated with Greenland warming at the onset of DO18. Since 64.0±0.1 ka B.P., the calcite δ¹⁸O values began to increase about 2.9 ‰ and this trend sustained near four thousand years. This results suggest that the weakening stage of summer monsoon in stalagmite DDH1 far exceeds that in Greenland ice core record. Other cave sediments show that it has a transition stage during 62.2~62.6 ka B.P. But the increased trend of δ¹⁸O values in DDH1 is still in one line without typical variations.
The onset of DO18 in DDH1 is simultaneous with other cave sediment in this region and Greenland ice core record, which confirmed the accuracy of our dating record. However its duration and amplitude are larger than other records. The large differences between Greenland ice core record and DDH1 may indicate some other mechanism. The pattern of DO18 in DDH1 revealed strongly resemblance with Antarctic ice core record and Cariaco Basin sediment. This reveals that it may be related with southern hemisphere and low latitude.
When DO18 event ended in north high latitude, δ¹⁸O values in Greenland ice core are still in negative level, which suggest that the temperature was still low in northern high latitude and AMOC was weak. So the heat was kept in southern hemisphere and that could enlarge the interhemispheric temperature gradient. This could induce the weakness of transequatorial flow and ITCZ migrated southward. In summer, the northern displacement boundary of ITCZ gradually shifted to south step by step. But the typical location of Didonghe Cave caused that it was affected by cooperation of the high and low latitude. The blocking of Tibetan Plateau and Qinling Mountain decreased the contribution of high latitude affection but increase the low latitude and south hemisphere influence. This finally results the feature of southern hemisphere more typical in this region. Superimposed the terrain influence and latitude effect, cave sediment values in this region are more negative and millennial climate event here has larger amplitude.
Finally, the transequatorial flow and influence of southern hemisphere that superimposed the blocking of Qinling Mountains and Tibetan Plateau cause the different appearance of DO18 in DDH1.
Key words:Didonghe/
stalagmite/
DO18 event/
H6 event/
East Asian Summer Monsoon/
oxygen isotope



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