Solid layered hydrothermal deposits have been retrieved using submersible ALVIN robotic arm over the Mid-Atlantic Ridge TAG field. These samples were analysed using Atomic absorption spectrometry (AAS) for their chemical composition and X-ray diffraction (XRD) to determine their mineralogy.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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. 372 of the related publication.