An initial investigation has been undertaken on the chemical composition of the manganese nodules. The results of chemical analyses on each layer of single nodules reveal the periodic patterns of distribution for Mn, Fe, Cu, Pb, Zn, Ni and Co contents. The variations strongly suggest that those of the elements in nodules from this region are, at least, climatically controlled.

Samples have been dried at 105°C for 4 hours and digested in a HF-HClO4-HNO3 solution. Only the soluble part was analysed.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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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.

Supplement to: Nohara, Masato; Nasu, Noriyuki (1977): Mineralogical and geochemical characteristics of manganese nodules from the Suiko Seamount, Northwestern Pacific Ocean - 2 - Geochemical aspect and its origin. Bulletin of the Geological Survey of Japan, 28(9), 615-621