中国多金属结核开辟区沉积物地球化学特征

Geochemical characteristics of sediments from the China Pioneer Area equatorial northeast Pacific Ocean

对中国多金属结核开辟区沉积物的详细研究表明 ,研究区内沉积物处于氧化至弱氧化环境 ,两种色调的沉积物在粒度分布特征以及化学组成上都存在着显著的差异 ,它们是不同沉积环境的反应 .不同色调之间的界面为一沉积间断面 .沉积物中的铁和锰具有不同的来源 ,铁可能以岩源碎屑为主 ,而锰则更可能是自生成因 .钙和镁以生物成因为主 .

In the China Pioneer Area, located in the western part of the area between the Clarion and Clipperton Fraction Zones, the topmost sediment column can be divided into two layers based on distinctive color and bioturbation properties: an upper pale brown layer (Unit A) and a lower dark brown layer (Unit B). Chemical properties in Unit A and Unit B are clearly different across the color boundary, which can be interpreted to be a hiatus. This results in an overall difference in sediment properties between Unit A and Unit B, that is, older Unit B sediment is higher in P 2O 5, MnO 2, CaO and Na 2O contents. Based on the correlation analysis, Mn and Fe in sediments have different genesis. The manganese mainly is authigenes, but Fe is from rock weathering. Therefore, the chemical differences in sediments are the results of sedimentation setting differences.