洞庭湖“四水”入湖河床沉积物主量元素地球化学特征及意义  

Geochemistry of major elements in bed sediments from inlets of the Four Rivers to Dongting Lake,China

作　　者：陈丹婷 彭渤[1,2] 方小红[1,3] 邬思成 刘静 赵亚方[1,2] 戴亚南 CHEN Danting;PENG Bo;FANG Xiaohong;WU Sicheng;LIU Jing;ZHAO Yafang;DAI Yanan(College of Geographic Science,Hunan Normal University,Changsha 410081,Hunan;Key Laboratory of Environmental Heavy-Metal Contamination and Ecological Remediation,Hunan Normal University,Changsha 410081,Hunan;College of City and Tourism,Hengyang Normal University,Hengyang 421000,Hunan)

机构地区：[1]湖南师范大学地理科学学院,湖南长沙410081 [2]湖南师范大学环境重金属污染机理与生态修复实验室,湖南长沙410081 [3]衡阳师范学院机构城市与旅游学院,湖南衡阳421000

出　　处：《第四纪研究》2021年第5期1267-1280,共14页Quaternary Sciences

基　　金：湖南省地理学一流学科(地理学-5010002)建设项目;湖南省高校科技创新团队支持计划项目(2014);国家自然科学基金项目(批准号:41073095)共同资助。

摘　　要：本研究利用X射线荧光分析仪(XRF)对洞庭湖"四水"(湘江、资江、沅江、澧水)入湖河床沉积物进行主量元素地球化学分析,探讨"四水"入湖沉积物主量元素组成特征及其影响因素。结果表明,洞庭湖"四水"入湖沉积物中SiO_(2)、Al_(2)O_(3)、Fe_(2)O_(3)、K_(2)O、P_(2)O_(5)、LOI等元素含量变化相对较小、分布特征相似;而MnO、MgO、CaO、Na2O等则含量变化较大,在各河流沉积物中分布差异明显。其中沅江和澧水入湖沉积物中MgO、CaO、Na2O等的含量明显高于湘江和资江沉积物,而MnO则反之;澧水沉积物TiO_(2)含量明显偏高。且湘江、资江、澧水沉积物中TiO_(2)、Al_(2)O_(3)、Fe_(2)O_(3)、MnO、MgO、CaO、P_(2)O_(5)、LOI等主量元素含量变化有明显的粒度效应,而沅江沉积物则不然。不同河流入湖沉积物主量元素组成差异明显,沉积物主量元素组成的明显差异与流域源岩岩性、化学风化作用、水动力条件等因素有关。其中湘江和资江沉积物主量元素组成主要与由上地壳+花岗岩组成的源岩有关;沅江沉积物元素组成受湖南板岩的影响明显;而澧水沉积物元素组成则是总体与上地壳元素组成相近似的区域源岩有关,并受长江沉积物影响。湘江和资江沉积物显示的风化程度明显高于沅江和澧水沉积物。但化学风化作用是通过不同抗风化能力岩石的空间分布而影响沉积物的元素组成。此外,湘江、资江、澧水沉积物元素组成受水动力条件影响,而沅江沉积物则不然。但水动力分选对沉积物元素组成的影响也受源岩岩性的控制。因此,流域源岩岩性是控制"四水"入湖沉积物主量元素组成的主要影响因素。The concentrations of major elements in bed sediments from inlets of the Four Rivers(Xiangjiang,Zijiang,Yuanjiang,and Lishui rivers)to Dongting Lake were measured using the X-ray fluorescence(XRF)technique,with purposes to characterizing the chemical compositions of the sediments and to understanding the possible factors that impact directly on the chemical composition of the sediments.The results show that the concentrations of major elements SiO_(2),Al_(2)O_(3),Fe_(2)O_(3),K_(2)O,P_(2)O_(5) and LOI are less variable,and they show similar distribution patterns in sediments of the Four River inlets.While,those of MnO,MgO,CaO and Na2O are significantly variable,and these elements display different distribution features in sediments of the Four River inlets.Meanwhile,the contents of MgO,CaO and Na2O in sediments of Yuanjiang and Lishui rivers are significantly higher than that of Xiangjiang and Zijiang rivers,while those of MnO vary oppositely.Moreover,sediments of the Lishui River has higher contents of TiO_(2) than the sediments of other three rivers do.In addition,the contents of TiO_(2),Al_(2)O_(3),Fe_(2)O_(3),MnO,MgO,CaO,P_(2)O_(5) and LOI in sediments of Xiangjiang,Zijiang,and Lishui rivers have obvious grain size effect,but not in sediments of Yuanjiang River.Thus,the major element compositions are different from the sediments of each river,and this difference was caused by lithological properties of the source rocks in the Four Rivers watersheds,and influenced by chemical weathering of the source rocks and the hydrological factors of different rivers.The major element compositions of the sediments from Xiangjiang and Zijiang rivers were determined mainly by source rocks that have comparable element compositions of the upper continental crust and the granitic rocks;those of Yuanjiang River were significantly impacted by the slate distributed in the watershed;and those of Lishui River were influenced by source rocks that have comparable compositions of the upper continental crust,and also possibly by the sedi

关 键 词：主量元素 源岩 化学风化作用 粒度 沉积物 洞庭湖 

分 类 号：P595[天文地球—地球化学] P941.78[天文地球—地质学]