RELATIONSHIP BETWEEN THE RATE OF GROWTH OF FERROMANGANESE NODULES AND THEIR MN/FE RATIO

Abstract

One of the main parameters describing the genetic features of ore deposition in the ocean and its intensity and history is the rate of growth of ferromanganese nodules (FMN). Despite much experimental work in recent decades, technical and financial difficulties have not yet allowed enough determinations of this parameter to be made for the purpose of better understanding the ore-generating process in deep-sea regions. The aim of this work was to search for an indirect method of determining the growth rate of nodules and prove its reliability. Study of the composition of nodules has already shown that the most sensitive indicator of the extent to which diagenetic metal remobilization affects the development of their ore material is the Mn/Fe ratio, and that the latter may serve as a geochemical criterion for distinguishing genetically different types of nodule. A direct relationship is observed between the Mn/Fe ratio and growth rate of nodules, because both parameters describe genetic features of their formation. Distinguishing features of the proposed indirect method of determining growth rates of FMN from their Mn/Fe2 ratio are its simplicity, availability and fairly high accuracy and the minimum expense needed for its use. In addition, it paves the way for mass determination of nodule-growth rates, so necessary for more profound study of the ore-generating process in deep-sea regions.