藏南沉错钻孔沉积物金属元素分布特征及其与粒度的关系  

Distribution features of elements in core sediments and their relationship with grain size in Lake Chen Co, southern Tibet

作　　者：王君波[1] 朱立平[1] 

机构地区：[1]中国科学院青藏高原研究所,北京100085

出　　处：《湖泊科学》2008年第6期715-722,共8页Journal of Lake Sciences

基　　金：国家自然科学基金项目(40571172;40701194);国家重点基础研究发展规划项目(2005CB422002);中国科学院知识创新工程方向性项目(KZCX3-SW-339)联合资助

摘　　要：对藏南沉错CC1孔216个沉积物样品进行了15种金属元素含量的测试,研究金属元素含量的分布特征,以及与粒度参数的变化关系.结果显示:金属元素的分布特征可分为三组,K、Na、Mg、Al、Ti、Ba、Cu、Zn、Fe、Pb、Cr、V等12种元素具有较为相似的变化趋势;Ca和Sr变化趋势相同;而Mn与其他任何一种元素都不相似.元素分布与粒度参数的相关分析结果表明,Ca、Ti、Pb的变化与沉积物粒度没有明显的关系;K、Na、Al、Ba、Cu、Fe、Cr、V等8种元素与沉积物粘土含量(<4μm)呈正相关关系;Mg、Zn、Mn与粉砂含量(4-63μm)呈正相关关系;而Sr与砂含量(>63μm)呈正相关关系.本研究中大部分元素的粒度效应与其他湖泊、海洋等水体沉积物中元素的粒度效应具有一致的结果.与本岩芯已有的过去1400年来的环境重建资料对比可以发现,在不同的环境变化阶段,元素组合特征都与湖区环境状况具有较好的对应性.其中大部分元素的含量变化受物源条件即流域风化侵蚀程度的影响,而Ca含量不受沉积物粒度变化影响,且与沉积物中碳酸盐含量、Sr/Ba具有很好的相关性,说明其变化受物源条件影响小,而主要与湖水理化性质、蒸发强度以及湖泊沉积过程有关.Altogether 15 metal elements concentration of 216 lake sediment samples from CCl core in Chert Co, southern Tibet were measured. Distribution features of all the metal elements and their relationship with grain size parameters was studied. The results showed that all the 15 elements could be divided into three groups according to their distribution features, i.e., 12 elements of K, Na, Mg, Al, Ti, Ba, Cu, Zn, Fe, Pb, Cr and V present similar variation trend against depth; Ca and Sr had very similar variation trend while Mn was not similar with any other element. The correlation analysis between elements concentration and grain size parameters indicate that the variation of Ca, Ti and Pb were not influenced by grain size distribution; 8 elements （K, Na, Al, Ba, Cu, Fe, Cr, V） show positive correlation with clay content （〈4pro） of the sediment; Mg, Zn and Mn have positive correlation with silt content （4-63μm） while Sr had good correlation with sand content （〉63μm）. The grain size effects of most elements in this study were coherent with other studies of elements grain size effects in lake sediments and marine sediments. Compared with reconstructed environmental information for the past ca.1400 years from this core, it could be found that the distribution characteristics of elements show rather good correspondence with environmental conditions during different stages. Variations of most elements show influences from sources of materials that is intensity of weathering and erosion in the drainage. However, Ca concentration was not affected by grain size of lake sediments, and performs very good correlation with carbonate content and Sr/Ba of sediments, indicating that influence from sources of materials was not the main controlling factor of Ca concentration, while physienchemical features of lake water, evaporation intensity and sedimentary process would probably the major influencing causations.

关 键 词：湖泊沉积物 元素分布 粒度 环境变化 沉错 

分 类 号：P595[天文地球—地球化学]