The samples used for this study are a subset from almost 200 surface samples from the western Nazca plate analyzed during the IDOE Nazca Plate Project. The subset was selected to provide coverage of the major physiographic units north of the Sala y Gomez Ridge and to encompass the major sediment types defined by factor analysis of selected major- and minor-element concentrations. The chemical data used in this study consist of bulk-sediment analyses by atomic absorption spectrometry. Samples were dissolved in Teflon-lined bombs using HF, HNO3, and HC1 heated to 125°C. H3BO3 was added to neutralize the HF and to dissolve insoluble fluorides. The precision of these analyses varies from less than 1% for the major elements and trace elements with concentrations greater than 200 ppm to approximately 20% for trace elements in the CaCO3-rich samples. For Fe,Cu,Ni and Zn the leached and residual parts listed in the original table have been reconciled.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 2, pp. 726, of the related publication.