Heavy metal contents in Fe-Mn nodules and crusts from R/V Vityaz polygons and stations in the East Indian Ocean

Regional variations in abundance, morphology, and chemical composition of Fe-Mn nodules have a zonal character. Due to circumcontinental zonality of terrigenous sedimentation the main mass of the nodules occurs in the pelagic part of the ocean, in areas of minimal sedimentation rates. In spatial variations in morphology and chemical composition of the nodules the latitudinal zonality is very clear and associated with latitudinal changes in facial conditions of sedimentation. Elevated contents of Mn, Ni, and Cu and of Mn/Fe ratio occur in nodules from the radiolarian belt. Changes of chemical composition of the nodules with depth (vertical zonality of mineralization) are confirmed. Local variations in abundance, morphology and chemical composition of the nodules are caused by ruggedness of relief and depth variations, variations in sedimentation rate, age of ore formation, intensity of diagenetic redistribution of metals.

铁锰结核（Fe-Mn nodules）在丰度、形态及化学组成上的区域分异具有分带性特征。受陆源沉积环陆分带性影响，铁锰结核的主体赋存于远洋海域内沉积速率最低的区域。在铁锰结核形态与化学组成的空间分异中，纬度分带性特征极为显著，且与沉积相条件的纬度变化密切相关。产自放射虫带的铁锰结核中，锰、镍、铜的含量以及锰铁比均偏高。已证实铁锰结核的化学组成随深度发生变化，即矿化垂直分带性。铁锰结核丰度、形态及化学组成的局部分异，主要由地形起伏、水深变化、沉积速率差异、成矿时代以及金属成岩再分配强度所导致。