摘要
中国东部季风区过去千年的水文变化已有大量研究并取得重要进展,但水文环境变化的起止时间、空间特征、温湿配置研究仍存在显著的区域差异,水文环境变化的驱动机制研究相对较少且不明确。以安徽升金湖沉积岩心为研究对象,分析元素地球化学指标的水文指示意义,结合总有机碳(TOC)、碳氮比(C/N)、无机碳(IC)等环境代用指标,讨论升金湖过去1000年的水文变化。结果表明:1)在1000~1350 A.D.,Ti、Rb/Sr、Cr、SiO_(2)含量呈波动下降,Sr、CaO含量呈低值波动,指示中世纪暖期水文环境向干旱化变化。2)在1350~1850 A.D.内可分为两个阶段;第一阶段(1350~1600 A.D.),Ti、Rb/Sr、Cr、SiO_(2)含量波动变化,但总体在高值水平,Sr、CaO含量为低值,指示流域降水较多;第二阶段(1600~1850 A.D.),Ti、Rb/Sr、Cr、SiO_(2)含量下降,总体呈低值水平,Sr、CaO含量为高值呈上升趋势,指示降水减少,说明小冰期水文环境由湿润转向干旱。3)1850~2000 A.D.,Ti、Rb/Sr、Cr、SiO_(2)含量呈上升趋势,Sr、CaO含量下降,指示降水增加,水文条件偏湿润。其中1137~1993 A.D.水文环境变化与历史文献记录的水文变化有良好的响应。区域重建结果表明:升金湖沉积物元素变化与大九湖泥炭重建降水量、江淮地区干湿指数、女山湖色度a^(*)/L^(*)干湿变化基本同步。进一步将升金湖沉积物元素变化与亚洲—太平洋涛动(APO)、北半球太阳辐照度变化对比发现具有较好的一致性,说明升金湖过去千年水文变化可能由APO与太阳辐照度变化驱动,同时在中世纪暖期与小冰期,东部季风区降水的南—北“偶极型”特征可能与亚洲—太平洋涛动密切相关,其水文环境演变既响应了半球性变化又有区域特征。
The hydrological changes in the monsoon region of eastern China over the past thousand years have been extensively studied and substantial progress has been made.However,there are significant apparent regional differences between the time interval,spatial characteristics and the combination of temperature and humidity.The driving mechanisms of humidity changes in the monsoon region of eastern China are also still unclear.To better understand the hydrological variations and internal and external mechanisms in the region over the past thousand years,it is necessary to continue to strengthen the reconstruction and driving mechanism of high-resolution hydrological changes.Lake Shengjin(30°15’-30°28’N,116°58’-117°14’E)is located in Chizhou city,Anhui province,on the southern bank of the Yangtze River and covers an area of 133 km~2.The lake consists of upper,middle and lower lakes.The climate of the lake basin is subtropical monsoonal,with an annual average temperature of 16.1℃and an annual average precipitation of 1600 mm.The 86 cm long sediment core SJPC19-3 was drilled in the shallow wetland area of the lake in March,2019.The sampling site is located at 30°20’N,117°00’E.The core was divided into intervals of 0.5 cm between 9 and 30 cm and intervals of 1 cm between 30 cm and 86 cm.The hydrological significance of geochemical elements was analyzed from reliable accelerator mass spectrometer(AMS)14C isotope data.The paleohydrological changes in Lake Shengjin during the past millennium were reconstructed from geochemical elements and combined with total organic carbon(TOC),carbon-nitrogen ratio(C/N),inorganic carbon(IC)and other environmental proxies.The changes were divided into three stages:(1)In Period I(1000-1350 A.D.),corresponding to the Medieval Warm Period(MWP),Ti,Rb/Sr,Cr and SiO_(2)content gradually decreased,and Sr and CaO content fluctuated at low values,indicating general aridification of the lake basin during the MWP.(2)Period Ⅱ(1350-1850 A.D.),corresponding to the Little Ice Age(LIA)
作者
金院
汪勇
胡洁
韩瑞超
项超生
JIN Yuan;WANG Yong;HU Jie;HAN RuiChao;XIANG ChaoSheng(School of Geography and Tourism,Anhui Normal University,Wuhu,Anhui 241002,China;Anhui Key Laboratory of Earth Surface Processes and Regional Response in Yangtze-Huaihe Basin,Wuhu,Anhui 241002,China;School of Spatial Informatics and Geomatics Engineering,Anhui University of Science&Technology,Huainan,Anhui 232001,China)
出处
《沉积学报》
CAS
CSCD
北大核心
2023年第1期219-232,共14页
Acta Sedimentologica Sinica
基金
国家自然科学基金项目(41771228)
安徽师范大学校博士启动金项目(2017XJJ36)。
关键词
元素地球化学
湖泊沉积物
升金湖
水文变化
亚洲—太平洋涛动
elemental geochemistry
lake sediments
Lake Shengjin
hydrological changes
Asia-Pacific oscillation
