北极楚科奇海近代沉积物稀土元素地球化学特征初探

The REEs GEOCHEMISTRY OF CHUKCHI SEA SEDIMENT CORE

于 1 999年夏季我国首次北极科学考察期间在楚科奇海采集了三个沉积物岩芯 ,并采用中子活化法 (INAA)测定了沉积物样品中稀土元素的含量。结果表明 ,其含量与东海大陆架细粒沉积物的稀土元素含量十分接近。稀土元素的含量沿沉积物岩心的垂直分布呈现出随深度轻微增大的趋势。页岩标准化的稀土元素配分模式相对平缓 ,Ce有轻度负异常 ,表明沉积物稀土元素除了陆源物质以外 ,也存在生物沉积作用的来源。稀土元素与指示陆源的元素Al具有良好的正相关关系 ,相对于地壳丰度所计算的富集因子接近于 1 ,进一步说明楚科奇海沉积物中的稀土元素以陆源物质输入为主 ,通过江河携带入海 ,最后随碎屑物质、悬浮物而沉积下来 ,并保持一种稳定的沉积状态。

Sediment core samples were collected from the continental shelf of the Chukchi Sea in July 1999 and rare earth elements (REEs) were measured by instrumental neurton activation analysis (INAA). The abundance of the REEs is very similar to values for fine grained continental shelf sediment. The downward profiles of the REEs show a slightly increasing trend with depth and the variation of the REEs is relatively smooth. The shale normalized REEs distribution pattern is rather flat with Ce negative anomaly, suggesting there exists biological source to the REEs in the sediment. The REEs is positively correlated with Al and enrichment factos calculated with respect to the crustal abundance is close to 1, which indicates the REEs in Chukchi Sea sediment are predominantly of continental origin.