Ferromanganese microconcretions (FMC) were hand picked from four sieved size fractions (100, 200, 325 and 400 mesh) of sediment samples from four depths in a one meter gravity core taken in the Mid-Atlantic Ridge FAMOUS Area. Scanning electron microscopy and electron microprobe analysis were used to relate surface morphology and metal content to depth of burial, size fraction and apparent sediment redox conditions. Upper sediment (0-2 cm) FMC's were typified by rounded, botryoidal forms while FMC's taken from the redox boundary region (42-46 cm) showed signs of dissolution and had depressed Fe to Mn ratios (1.32 at the surface, 0.62 at 42-44 cm). Well crystallized pyritihedra were found in samples taken from the base of the core as well as in samples from the redox boundary.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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.