A suite of three palagonites from pillowed basalts collected from within the Mid-Atlantic Ridge rift valley between 25°N and 30°N wer analysed along with another suite of two hydrothermally altered basaltic breccias and four hydrothermal manganese crusts collected from the TAG hydrothermal field at 26°N on the Mid-Atlantic Ridge. These specimen were collected during Trans-Atlantic Geotraverse (TAG) NOAA cruises using the R/V Discoverer. Two more hydrogenous ferromanganese crusts wer also analysed. They were collected from the eastern extension of the Atlantis Fracture Zone aboard the R/V Kurchatov in 1975. Radiochemical neutron activation analysis has been used to determine Tl, Rb. Cs. Co and Cr. Iron, Mn, and Mg concentrations in the crystalline samples and Mn crusts have been determined by AAS. K was determined by flame photometry, and S in these samples (as well as five glasses) has been determined with a Leco Automatic Sulfur titrator.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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. 1306-1307 of the related publication.