摘要
对南极菲尔德斯半岛西湖沉积岩芯进行中子活化分析,得到沉积物的25个化学元素含量。研究发现西湖沉积物的元素含量由高至低的顺序为:Fe>Ca>Na>Sr>Ba>Zn>Cr>Sc>Ce>Co>Nd>As>Rb>La>Sm>Hf>Yb>Eu>Th>Cs>Tb>U>Lu>Ta>Au;沉积物的化学元素组成与环境风化强度密切相关,在南极岩石风化过程中,元素Fe,Rb,Co,Cr和Ba含量较稳定,而元素Ca,Zn,Na,Ta和U发生不同程度的淋失;元素Na,Hf,Ca和Ta之间,Co,Ce,Fe,Sr,Nd,Sm,Eu,Yb,Lu和Tb之间,Cs,As,La,Sc,Rb,Th和Ba之间共生关系密切,这些元素在沉积层次上的变化具有一致性;西湖沉积物稀土分布模式与安山岩相似。
Through neutron activation analysis （NAA）, the contents of 25 chemical elements in the 30 lake sediment samples are measured, respectively. The samples were taken from the Antarctica lake core at 5 cm intervals. Based on the results, the geochemical characteristics including elements contents, chemical components change with weathering degree, correlativity between chemical elements are discussed in the paper. The results show that elements sequence of the Xihu lake core is ： Fe〉Ca〉Na〉Sr〉Ba〉Zn 〉Cr〉Sc〉Ce〉 Co〉 Nd〉 As〉 Rb〉 La〉Sm〉 Hf〉 Yb〉 Eu〉 Th〉Cs〉 Tb〉U〉Lu〉Ta〉Au. The contents range of the abundant elements, such as Fe, Ca and Na, is 1.46-6. 79%; For the middle abundant elements Sr and Ba, the contents range is 0. 123‰- 0. 480‰; For the trace elements of Zn, Cr, Sc, Ce, Co, Nd, As, Rb and La, their contents range is 0.012 5‰-0. 107‰; And the uhramicro-elements, such as Sin, Hf, Yb, Eu, Th, Cs, Tb, U, Lu and Ta, their contents vary from 0.000 115‰ to 0. 005 04‰. Element Au is the least, and its average content is only0.006 28‰. Meanwhile, it is found that on the vertical section of the lake core, the contents of chemical elements are variable. For instance, the variance coefficients of the elements such as Ca, Cr, Taand Au are above 20%, while those of the elements La, Ce, Sin, Hf, Sc and Th are below 10%. Chemical components of the lake core were strikingly affected by the weathering intensity. During the process of weathering, the contents of the elements Fe, Rb, Co, Cr and Ba in the lake core scarcely varied, while the elements Ca, Zn, Na, Ta and U could be eroded away. The results of clustering analysis demonstrate three element groups： one group of Na, Hf, Ca, Ta and Co, another group of Ce, Fe, Sr, Nd, Sin, Eu, Yb, Lu, Tb, and the third group of Cs, As, La, Sc, Rb, ThandBa. In the group, the elements were closely related and changed accordingly on to deposit layers. The REE distribution pattern of the Xihu lake is similar to that of andesite.
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2005年第5期460-465,共6页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
福建省科技厅国际合作重点项目(2003I015)
福建省教育厅资助项目(JA02190)
关键词
南极
湖泊沉积物
元素地球化学特征
Antarctica
lake sediment
elements geochemical characteristics
