The ferromanganese crust samples studied have been taken from Central Pacific seamount areas during the research cruise Midpac 81. Two ferromanganese crust generations with different ages have been identified; in between a period of carbonate sedimentation and an episode of phosphorite formation have taken place. The older crust generation, therefore, is mostly impregnated by carbonate-apatite. Metal concentration was determined by Atomic Absorption Spectrophometry by the Technical University of Claustahl.

Values in wt.% of dried substance----------------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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 Table is digitized from Table 1 - Part 2, pp. 76 of the related publication.