Average chemical composition by size categories of manganese nodules and crusts collected from the R/V Sonne Cruise SO-06, Sept-Oct, 1978 in the Pacific Ocean

Manganese nodules collected from three areas (C, F, and G) on a N-S equatorial Pacific transect at 134° W by R. V. Sonne show differences in size, morphology, surface density and composition which can best be interpreted in terms of the biogenic theory of nodule formation. These data indicate that the biogenic hypothesis is central to an understanding of manganese nodule genesis in the equatorial Pacific and in particular influences the nodule shape, surface texture, rate of growth, composition, and mineralogy. The nodule characteristics in this region are also influenced by the hydrological characteristics of the bottom water, sedimentation rates, local geological and tectonic conditions (including seeding eflects) and topography.