云南华坪全新世大暖期百年尺度的季风气候的石笋记录  

Century-scale monsoon climate fluctuations from a stalagmite recorded during the middle Holocene Epoch in Hulu cave of Huaping county,Yunnan

作　　者：张美良[1] 朱晓燕[1] 吴夏[1] 潘谋成[1] ZHANG Meiliang;ZHU Xiaoyan;WU Xia;PANG Moucheng(Institute of Karst Geology,CAGS/Karst Dynamics Laboratory,Guilin,Guangxi 541004,China)

机构地区：[1]中国地质科学院岩溶地质研究所/国土资源部、广西岩溶动力学重点实验室

出　　处：《中国岩溶》2019年第5期804-814,共11页Carsologica Sinica

基　　金：国家自然科学基金(批准号41372190,41501222);中国地质科学院基本科研业务费(YYWF201513);地质调查项目(DD20160305)

摘　　要：通过对云南华坪葫芦洞FL4石笋进行高精度的ICP—MS—^(230)Th/U测年和高分辨率的碳、氧同位素分析,建立了该地区6 060-4 185 a BP间高分辨率的西南季风气候变化时间序列,进而揭示了该时段发生的3次季风减弱事件。这3次百年尺度(持续时间为90~240a)的干旱寒冷事件,分别发生在6 060-5 950 a BP、5 380-5 140 a BP、4 810-4 620 a BP,呈台阶状演变;而石笋的碳同位素记录揭示了2次强降水事件,分别发生在5 503-5 443 a BP和4 210-4 185 a BP,持续时间分别为25a和60a。石笋碳、氧同位素记录的西南季风减弱以及强降水事件明显受太阳辐射强度的控制。分辨率为3~10 a的碳、氧同位素记录表明,在百年尺度的西南季风气候变化上,叠加了一系列十年尺度的气候突变事件,呈锯齿状的高频波动。这些短时间尺度的季风气候波动事件与树轮14C残差、冰芯记录极为相似,反映低纬度地区石笋记录的季风气候与高纬度及北极地区的气候具有极好的可比性,可能主要是受中低纬度太阳辐射强度以及北半球大气环流的影响,太阳辐射强度的变化是控制印度季风的快速推进或退出(萎缩)以及百年尺度上的气候波动的主要动因。A 1875-year(6060-4185 a BP)high resolution time sequence recording the Southwest Monsoon cli mate changes was established from a stalagmite(F L4), Hulu cave,H uaping,C hina,on the basis of ICP- MS-230Th series dating and Carbon and Oxygen isotope analysis. Three century-scale events of monsoon weaken ing in the Middle Holocene(6060-4185 a BP) were recorded,accompanied by three drought events that oc curred during 6060-5950 a BP,5380-5140 a BP and 4810-4620 a BP,respectively,lasting for 90~240 years. Carbon isotope data suggested 5497-5442 a BP and 4210-4185 a BP witnessed two events of heavy rain fall,w ith a duration from 25 years to 55 years. It is obvious that the events of monsoon weakening and heavy rain fall were controlled by the drive of insolation. Carbon and Oxygen isotope records,w ith the resolution of 3~10a on average,indicated that a series of decadal-scale abrupt climate changes were superimposed upon the century- scale monsoon climate changes,carrying the characteristic of indentation. The short time-scale of the monsoon cli mate fluctuations were similar to the Δ^( 14) C of growth ring and ice cores,demonstrating that monsoon climate changes recorded by stalagmites in lower latitude areas are comparable to the climate changes in the Arctic Re gions. Monsoon climate might be mainly influenced by the strength of insolation in low and middle latitude areas and the General Circulation of the Northern Hemisphere. It is the changes of the strength of insolation that controls the evolution of Indian Monsoon. Stalagmite records reflected that rapid strengthening or weakening of Indian mon soon and century-scale climates fluctuations resulted from the changes of insolation strength.

关 键 词：石笋 中全新世 西南季风 降水事件 华坪葫芦洞 云南 

分 类 号：P532[天文地球—古生物学与地层学]