Manganese nodules were taken from free-fall grabs at various stations of the Manganese Nodule Program BOMDROP cruise MN75-03. The underlaying sediment was essentially a siliceous ooze overlaying induretaed carbonate formations. Polished sections of manganese nodules have been investigated using X-ray microprobe analysis by the author at Sandia National Laboratories, USA. Various local zones of the cross-sections have been investigated including outside surface, local protruding botryoids, inside layers and todorokite rich cores. The table presents the average chemical measurements along each of the examination profiles scanned with the microprobe.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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