Ocean clay samples associated with ferromanganese nodules and crusts have been analysed for their 143Nd/144Nd isotopes ratio. Nd is separated from samples after HF-HNOa decomposition by a two-column mixed solvent anion-exchange technique. Nd samples were then loaded as chlorides on a triple filament assembly using Ta side filaments and a Re centre filament. Isotopic analyses were performed on a Vacuum Generators Micromass 30 mass spectrometer equipped with an on-line computer facility for data analysis.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 - Part 1, pp. 326 of the related publication.