The authors have selected for analysis a manganese nodule from Station 20 of the PLEIADES Mn7601 campaign. This "apple" shaped nodule (6.5x3.0 cm) was laying on a bed of siliceous ooze (see illustrations). Electron microprobe measurements were made on the same section as that used in the alpha-track studies. Prior to the microprobe analyses, however, the nodule slab was highly polished to reduce surface relief A MAC electron microprobe was employed and the electron beam was focused to a dmmeter of about 2 micrometers using 15 kV and 300 mA.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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. 164-165 of the related publication.