Manganese nodules were selected from various areas of the Pacific, Indian and Atlantic ocean. They were analysed using a mercury vapour discharge technique. The minimum precision of the technique as determined by multiple analyses of individual samples was +- 12 per cent of the amount present.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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. 54 of the related publication. However, the authors have apparently transmitted to NOAA-NGDC more analysis results for some samples than in the published table of the report.