Initial attempts to classify the composition of manganese nodules in the Pacific Ocean illustrated the paucity of data for the Southwestern Pacific Basin. Recent major element analyses of 16 manganese nodules from different stations in the Southwestern Pacific Basin collected during the 1974 R. V. Tangaroa cruise are presented. They have shown high contents of elements associated with the silicate phase of nodules (36—54% as oxides on a dry weight basis). The high contents o f the elements may be due to the incomplete replacement of the volcanic nuclei of the nodules by iron-manganese oxides in the initial stages of nodule formation. Some elements (e.g. Na, Mg, Si and Ti) show particularly wide variations in composition in these nodules. Chemical analyses were performed on bulk nodule samples (including nucleus) using X-ray fluorescence spectrometry. Samples were ground in a SFEX mill grinder and ignited at 1000°C in a Pt crucible to drive off volatiles. They were then reduced to a glass bead and reground for analysis.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 VIII, pp. 158, of the related publication.