Ocean clay samples associated with ferromanganese nodules and crusts have been analysed for their 143Nd/144Nd isotopes ratio. Sr was separated for isotopic analysis using conventional cation-exchange techniques with a total blank of 1-2 x 10minus-10 g Sr. For those samples leached with acetic acid (HOAC), Sr isotope data are reported for both leachates and residues when appropriate and as bulk sample analyses otherwise. Sr isotope analyses were made on the a Vacuum Generators Micromass 30 mass spectrometer using a single Ta-filament technique.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 2, pp. 326 of the related publication.