Manganese nodules have been shown to consist of heterogeneous mixtures of a variety of biogenic, detrital and authigenic particles in a finely laminated structure. On a microscale those laminations exhibit variations in Mn, Fe and trace metal concentrations which perhaps reflect changing environmental conditions on the sea floor or in the rain of particles that fall on the nodule. Local X-ray fluorescence analysis reveals that the bottom of nodules are enriched in Mn, Ni and Cu while being relatively depleted in Fe, whereas the opposite pattern is evident for the top of the nodule. The equatorial rim demonstrates the most variable distribution of the elements in relation to other areas on the nodule.

From 1983 until 1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions. At the time it was the most extended data compilation on ferromanganese deposits world wide. Initially published in a proprietary format incompatible with present day standards it was jointly decided by AWI and NOAA to transcribe this legacy data into PANGAEA. This transfer is augmented by a careful checking of the original sources when available and the encoding of ancillary information (sample description, method of analysis...) not present in the NOAA-MMS database.This dataset represents the digitized Table 4, pp. 438 of the related publication.