The deposits from the DSDP Site 424 hole are divided into two major categories according to the relative proportions of the green clay-rich fractions and the presence of Fe-Mn concretions. The Fe-Mn concretions are associated with interlayers of pelagic foraminiferal nannofossil ooze from the Upper Pleistocene. This carbonate ooze is rather enriched in Mn by comparison with the green clay-rich fractions. Representative carbonate ooze samples have been chemically analysed by Cambon P. and Etoubleau J. from COB-CNEXO (Ifremer) using X-ray fluorescence.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 3, pp. 468, of the related publication.