A CCOP/SOPAC cruise aboard C.I.G.M.F.V. Ravakai in June 1976 found a high density manganese nodule field in the south Penrhyn Basin between Aitu-taki and Penrhyn in the Cook Islands. Nodules were recovered at 9 of the 12 stations occupied, and underwater photographs taken at 6 of these 9 stations indicate about a 90% nodule coverage of the sea floor corresponding to a surface density of nodules in the range 15-30 kgm/nf2 . Stiff grayish brown (5 YR 3/2) abyssal clay was recovered at all stations. Selected manganese nodules from each station were analysed at the University of Hawaii by E. Okazaki using an XRF Quantometer. Analysis are expressed as element weight percent on a dry weight basis.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 1, pp. 78, of the related publication.