台湾海峡沉积物中锆、铌、镧、铈、钇的地球化学特征

GEOCHEMICAL CHARACTERISTICS OF Zr, Nb, La, Ce, Y IN SEDIMENTS OF TAIWAN STRAIT

本文对台湾海峡中、北部(24°20′—26°N,118°48′—121°E)表层沉积物中的Zr(锆)、Nb(铌)和稀土元素La(镧)、Ce(铈)及Y(钇)的区域含量分布特征及控制因素等进行描述与探讨。研究结果发现,上述元素的含量随着水深的不同而变化,在40m水深以浅,zr、Nb、Ce、Y含量较高,La、Ce、Y含量于水深40—50m或50—60m处有一最低值。

In this paper the regional distribution characteristics of Zr, Nb, and rare--earth element La, Ce, Y contents and the factors influencing distribution are explored.1. Relation between content and grain size of sediments. Content of Zr and rare-earth elements in clay-class sediments is highest.2. Relation between content and depth. High content area is on the offshore area where depth is less than 40 m.3. Relation between content and hydrodynamics. Taiwan Strait is affected by Zhejiang-Fujian offshore current, the strait's warm current and high temperature-high salinity seawater from the open sea. Among them influence of the strait warm current is strongest,causing a low content area in the middle of the strait.4. Relation between content and sedimentary mechanism. Zr and rare-earth elements are almost adsorbed completely by clay minerals in seawater (pH >7.8) . There is no close relation between the content of these elements and CaCO3, the elements are not enriched by biogenic sediment and they negatively correlated with the content of silicate silicon, as silicate silicon plays a dilution role.