安徽巢湖沉积物常量元素特征及其揭示的流域风化强度演变  

Characteristics of Macroelements and Revealed Evolution of Weathering Intensity in Sediments of Chaohu Lake,Anhui,China

作　　者：李晨晨 吴立[2,3] 毛龙江 马春梅[5] 管后春 LI Chen-chen;WU Li;MAO Long-jiang;MA Chun-mei;GUAN Hou-chun(Institute of Science and Technology History and Meteorological Civilization,Nanjing University of Information Science&Technology,Nanjing 210044,Jiangsu,China;School of Geography and Tourism,Anhui Normal University,Wuhu 241002,Anhui,China;Provincial Key Laboratory of Earth Surface Processes and Regional Response in the Yangtze-Huaihe River Basin,Anhui Normal University,Wuhu 241002,Anhui,China;School of Marine Sciences,Nanjing University of Information Science&Technology,Nanjing 210044,Jiangsu,China;School of Geography and Ocean Science,Nanjing University,Nanjing 210023,Jiangsu,China;Geological Survey of Anhui Province,Hefei 230001,Anhui,China)

机构地区：[1]南京信息工程大学科技史与气象文明研究院,江苏南京210044 [2]安徽师范大学地理与旅游学院,安徽芜湖241002 [3]安徽师范大学江淮流域地表过程与区域响应安徽省重点实验室,安徽芜湖241002 [4]南京信息工程大学海洋科学学院,江苏南京210044 [5]南京大学地理与海洋科学学院,江苏南京210023 [6]安徽省地质调查院,安徽合肥230001

出　　处：《地球科学与环境学报》2024年第6期758-774,共17页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金项目(41771221,42271173);安徽省“十四五”规划重点项目(2022BFAFZ01365)。

摘　　要：全新世是人类文明形成发展的重要时期,把握全新世以来气候变化规律将有助于理解全球气候变化,科学应对突发气候事件。通过对安徽巢湖SZK1507孔岩芯沉积物的常量元素含量及其比值特征进行分析,结合AMS^(14)C测年重建了巢湖流域10.8 cal.ka B.P.以来的风化强度演变过程,揭示了流域气候环境变化和可能存在的气候突变事件,并初步探讨了化学风化强度可能的影响因素。结果表明:(1)环境代用指标化学蚀变指数(CIA)、残积系数(Ki)的谷值与风化淋溶系数(Ba)、退碱系数(w)的峰值均出现在砂层和粉砂层,表明砂层和粉砂层的化学风化程度较弱于其他层位。(2)阶段Ⅰ(10.8~9.9 cal.ka B.P.)和阶段Ⅲ(9.3~5.7 cal.ka B.P.)化学风化作用强烈,阶段Ⅱ(9.9~9.3 cal.ka B.P.)化学风化作用弱,阶段Ⅳ(5.7~2.3 cal.ka B.P.)化学风化作用逐渐减弱,阶段Ⅴ(2.3 cal.ka B.P.以来)化学风化作用变化频繁,整体呈减弱特征;此外,化学风化强度与气候变化具有较好的一致性,揭示了全新世以来巢湖流域经历了偏湿→偏干→湿润→湿润转干→变干为主的气候环境演变过程。(3)风化强度变化记录很好地表征出9.3、8.2、4.2和2.8 ka B.P.气候突变事件。通过对巢湖湖相沉积物11000 cal.a B.P.以来的化学蚀变指数、30°N夏季太阳辐射量、神农架三宝洞δ18O记录、神农架大九湖δ^(13)C记录等进行综合对比发现,构造抬升运动提供了稳定的陆源碎屑物质,流域气候环境条件是化学风化强度的控制因素,气候变化背景下的植被演替也影响着风化作用强弱,而粒度主要影响着沉积物化学元素组成。Holocene is an important period for the formation and development of human civilization.Study on the laws of climate change since Holocene will help to understand global climate change and scientifically respond to abrupt events.The major element contents and ratio characteristics in core SZK1507 of Chaohu Lake were conducted;combined with AMS^(14)C dating,the evolution process of weathering intensity in Chaohu Basin since 10.8 cal.ka B.P.was rebuilt,and the process of climate and environmental change in the basin and possible climate abrupt events were revealed,while the possible influencing factors of chemical weathering intensity were preliminarily explored.The results show that①the valley values of environmental substitution index,such as chemical index of alteration(CIA)and Ki,as well as the peak values of Ba and w,both appear in the sand layers and silt layers,indicating that the chemical weathering degree is weaker than that of other layers.②During the period I(10.8-9.9 cal.ka B.P.)and the periodⅢ(9.3-5.7 cal.ka B.P.),the chemical weathering intensity is strong;and weaker chemical weathering intensity occurs in the periodⅡ(9.9-9.3 cal.ka B.P.);during the periodⅣ(5.7-2.3 cal.ka B.P.),the chemical weathering intensity gradually weakens;during the periodⅤ(from 2.3 cal.ka B.P.to the present),the chemical weathering intensity changes frequently,showing an overall weakening feature;in addition,there is a good consistency between the intensity of chemical weathering and climate change,revealing that Chaohu Basin has undergone a climate and environmental evolution process since Holocene,which is relatively wet→relatively dry→wet→wet to dry→dry.③The variation of weathering intensity also effectively records 9.3,8.2,4.2,and 2.8 ka B.P.abrupt events.By combining with the CIA,summer solar insolation since Holocene at 30°N,δ18 O records of Sanbao Cave in Shennongjia Mountains,δ^(13)C of Dajiu Lake peat section in Shennongjia Mountains and other comprehensive comparisons since 11000 cal.a B.P.,i

关 键 词：全新世 风化强度 环境演变 气候事件 影响因素 常量元素 AMS^(14)C测年 巢湖 

分 类 号：P512.12[天文地球—地质学] P595