广西桂林岩溶湿地沉积记录的中全新世以来水文气候变化  

Hydroclimatic changes since the middle Holocene recorded from a karst wetland in Guilin,Guangxi

作　　者：周建超 殷建军[2,3,4] 袁道先[2,5] ZHOU Jianchao;YIN Jianjun;YUAN Daoxian(Institute for Chengdu-Chongqing Economic Zone Development,Chongqing Technology and Business University,Chongqing 400067,China;Institute of Karst Geology,Chinese Academy of Geological Sciences,Key Laboratory on MNR&CZAR,Guilin,Guangxi 541004,China;Guilin Karst Geology Observation and Research Station of Guangxi/Guangxi Pingguo Karst Ecosystem National Field Scientific Observation and Research Station,Pingguo,Guangxi 531406,China;International Research Centre on Karst under the Auspices of UNESCO,National Center for International Research on Karst Dynamic System and Global Change,Guilin,Guangxi 541004,China;School of Geographical Sciences,Southwest University,Chongqing 400715,China)

机构地区：[1]重庆工商大学成渝地区双城经济圈建设研究院,重庆400067 [2]中国地质科学院岩溶地质研究所/自然资源部岩溶动力学重点实验室,广西桂林541004 [3]桂林岩溶地质广西野外科学观测研究站/广西平果喀斯特生态系统国家野外科学观测研究站,广西平果531406 [4]联合国教科文组织国际岩溶研究中心/岩溶动力系统与全球变化国际联合研究中心,广西桂林541004 [5]西南大学地理科学学院,重庆400715

出　　处：《地质学报》2025年第3期991-1004,共14页Acta Geologica Sinica

基　　金：自然资源部/广西岩溶动力学重点实验室开放课题(编号KDL&Guangxi202101);中国地质科学院岩溶地质研究所基本科研业务费项目(编号2021002);重庆工商大学高层次人才科研启动项目(编号1955031);重庆工商大学长江上游经济研究中心开放课题(编号KFJJ2019005)联合资助的成果;重庆市教委人文社科项目(编号20JD071)。

摘　　要：重建我国东部季风区全新世水文气候变化历史对于理解东亚夏季风的驱动机制及预测其未来变化十分重要,然而,迄今为止,对我国华南地区全新世水文气候变化的认识还不够清晰。本文在广西桂林岩溶湿地八仙岩获取了一连续沉积剖面(BX),对其开展了AMS^(14)C定年及粒度分析,探讨了该区域中全新世以来的水文气候变化。通过端元模型分析(EMMA)提取了具有明确环境指示意义的三个粒度端元(EM1-3),其中,EM1代表了湿地水位变化,间接指示季风降水;EM3指示极端水文事件。据此,恢复了研究区8.5 ka BP以来湿地演化及季风降水变化历史。结果表明,8.5 ka BP以来区域降水呈逐渐减少的趋势,并可划分为三个阶段:8.5~6.35 ka BP,区域降水丰富,八仙岩发育浅水湖泊;6.35~4.15 ka BP,区域气候逐渐变干,八仙岩退化为湖沼湿地,其中在6.25~6 ka BP、5.2~4.9 ka BP和~4.5 ka BP发生了三次极端水文事件;4.15~0.15 ka BP,湿地水位持续降低,但在1.3~0.7 ka BP有短暂回升。区域对比分析表明,八仙岩沉积记录的季风降水变化历史与东亚夏季风强度变化趋势一致。周期分析还表明,太阳活动是我国华南地区季风降水变化的主要控制因素。此外,低纬海-气相互作用过程(如ENSO)对我国华南地区的季风降水也有重要影响。The East Asian summer monsoon(EASM)exerts a dominant influence on the hydroclimate of eastern China.Variations in monsoon precipitation,especially extreme events,have profound impacts on societal and economic activities in the region.Understanding Holocene EASM variability is critical for deciphering its forcing mechanisms and predicting future changes.However,uncertainties in dating results,compounded by the lack of high-resolution,well-dated sedimentary records in South China,have hindered a clear understanding of Holocene hydroclimate variability in eastern China.This study presents a continuous sedimentary section(BX)from the Baxianyan karst wetland in Guilin,Guangxi.AMS^(14)C dating and grain size analysis were conducted,revealing three distinct grain size end members(EM1-3)with clear environmental significance,extracted using end-member model analysis(EMMA).EM1 reflects changes in wetland water level,indirectly indicating monsoon precipitation.EM3 indicates the occurrences of extreme hydrological events.Based on EMMA results,the evolution of the wetland and monsoon precipitation changes since 8.5 ka BP were recovered.The results reveal a gradual decreasing trend in regional precipitation since the middle Holocene,showing three stages:①From 8.5 to 6.35 ka BP,higher precipitation prevailed,leading to the formation of a shallow lake in Baxianyan;②between 6.35 and 4.15 ka BP,Baxianyan transitioned into a swamp under a progressively drying climate,with three extreme hydrological events identified at 6.25~6 ka BP,5.2~4.9 ka BP,and~4.5 ka BP;③from 4.15 to 0.15 ka BP,water levels continued to decline,with a brief rise occurring between 1.3 and 0.7 ka BP.Comparison with regional records indicates that the monsoon precipitation history recorded in the Baxianyan sedimentary sequence is consistent with the East Asia summer monsoon intensity.Periodicity analysis of EM1 suggests that solar activity has been the main driver of monsoon precipitation changes since the middle Holocene.In addition,atmosphere-ocean inter

关 键 词：华南地区 岩溶湿地 粒度 全新世 水文气候变化 极端水文事件 

分 类 号：P46[天文地球—大气科学及气象学]