Samples were cleaned with hydrogen peroxide (H2O2) and acetone [(CH3)2CO] and dried at 60 °C for at least 30 min. Manganese nodules and their underlaying red limestone do not contain any sulfur to the opposite of the overlaying manganese carbonate rich marlstones.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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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.