Marine manganese nodules dredged from five locations in the central Pacific Ocean were studied for their mineral composition in todorokite. They were compared with pisolitic manganese ore from 'G' quarry on Groote Eylandt, off the north coast of Australia. The chemical composition of the todorokite rich areas in the samples was determined using Electron microprobe analysis (EPMA) using an ARL type EMX microprobe, with 52.5° take-off angle. Counting data were fully ZAF corrected ( ZAF model, see: https://link.springer.com/article/10.1007/BF01196142 ). All results listed are non-normalized, and totals are less than 100% because the phases are hydrated.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 III, pp. 255 of the related publication.