(Table 2) Contents of P2O5 and REE in Late Quaternary phosphorite nodules from Chile and Peru shelves

Changes in concentration levels and speciation of heavy metals during sedimentation on example of a typical semi-closed bay, where bottom sediments have formed due to river run-off, are under consideration. It is shown that due to desorption of mobile manganese, zinc and copper entered the bay with river suspended matter, their total contents in bottom sediments decrease and percentages of lithogenic forms increase. Contents and speciation of iron in bottom sediments are determined by its participation in coagulation of river colloids in the mixing zone and by mechanical differentiation of sedimentary material.

本研究以典型半封闭海湾为研究对象，该海湾的海底沉积物由河流径流沉积形成，探讨了沉积过程中重金属的浓度水平与赋存形态（speciation）的变化特征。研究表明，随河流悬浮物输入海湾的锌、铜以及可移动态锰，因可移动态锰的解吸作用，其在海底沉积物中的总含量有所降低，而陆源成因（lithogenic）形态的占比则有所上升。海底沉积物中铁的含量与赋存形态，取决于其在河海混合带参与河流胶体的絮凝过程，以及沉积物质的机械分异作用。