湖泊沉积物不同赋存状态Rb、Sr地球化学记录研究  

The Geochemical Records of Rb and Sr of Different Forms in Lake Sediments

作　　者：陈敬安[1] 曾艳[1,2] 王敬富[1,2] 杨永琼[1,2] 杨海全[1,2] 计永雪[1,2] 

机构地区：[1]中国科学院地球化学研究所环境地球化学国家重点实验室,贵阳550002 [2]中国科学院大学,北京100049

出　　处：《矿物岩石地球化学通报》2013年第4期408-417,共10页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金资助项目(41021062;40873084);国家科技支撑计划资助项目(2011BAC02B02)

摘　　要：湖泊沉积物中不同赋存状态的Rb、Sr记录了不同的表生地球化学过程和环境信息。本文选取广东湖光岩玛珥湖和内蒙古岱海作为研究对象,对沉积物柱芯不同赋存状态Rb、Sr的剖面变化进行了对比研究,发现湖光岩玛珥湖和岱海沉积物中不同赋存状态Rb、Sr的剖面变化存在显著差异,笼统利用沉积物全样Rb/Sr比值来反映流域气候环境变化是不合适的,甚至可能得出错误的结论。湖光岩玛珥湖和岱海沉积物中Sr非残渣态/Rb总与TIC、TOC、TN、C/N等环境代用指标的综合对比研究表明,Sr非残渣态/Rb总可有效指示流域化学风化变化:当流域化学风化作用增强时,沉积物Sr非残渣态/Rb总增大;当流域化学风化减弱时,沉积物Sr非残渣态/Rb总降低。因此,对不同类型的湖泊,在利用湖泊沉积物Rb、Sr地球化学记录反演古气候/古环境变化时,需综合考虑湖盆流域地质地理背景和湖泊自身特点,选用合适的研究方法,才能得出可靠的结论。Rb and Sr of different forms in lake sediments may record different geochemical and environmental processes.In this study,the variation patterns of Rb and Sr of different forms in sediments of the Huguangyan Lake and the Daihai Lake were investigated.The results show that Rb and Sr of different forms display obviously different variation patterns,and that using Rb/Sr ratios of bulk lake sediments to reflect chemical weathering is not appropriate,even wrong.The comparison of（non-residual Sr）/Rb ratio with TOC,TIC,TN and C/N of the sediments in both the Huguangyan Lake and the Daihai Lake showed that the（non-residual Sr）/Rb ratio effectively reflected the change of chemical weathering.When the chemical weathering enhances,the（non-residual Sr）/Rb ratio increases;when the chemical weathering weakens,the（non-residual Sr）/Rb ratio decreases.In different types of lakes,the sources and forms of Rb and Sr of sediments are different.Geochemical background,geographical feature and climate of the basin and lake characteristics must be investigated to select appropriate application method of using Rb and Sr in lake sediments to reflect paleoclimate/paleoenvironment.

关 键 词：湖光岩玛珥湖 岱海 沉积物 Rb、Sr赋存状态 化学风化 

分 类 号：P595[天文地球—地球化学] X142[天文地球—地质学]