Ferromanganese nodules at DOMES sites A, B, and C collected by the R/V Oceanographer. Nodules selected for bulk analysis were taken from the dominant size class of each box core when possible. A slice taken through the nodule center, or the entire nodule in the case of small nodules, was used for chemical analysis using X-ray fluorescence technique. Before analysis samples were washed free of sediment and sea salt, dried at 110° C, and powdered. Measurements were performed on the fraction soluble in 6N HCl.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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.