67 samples of manganese nodules were obtained during the GH79-1 Cruise of R/V Hakurei Maru in the northern part of the Central Pacific Basin. All nodules were immersed in running water and then ion-free water. After air-dried, samples were ground to under 150 mesh. The ground samples were encased in small paper bags, dried at 20-25°C for 24 hours, and then kept in a desiccator. In most cases an analysis was done for mixed ground sample of two or three different size classes of nodules from each box corer or freefall grab. Mn, Fe, Ni, Cu, Co. Pb, and Zn were determined by atomic absorption spectrometry. Each sample of 0.1 g was decomposed with a mixture of 5 ml of hydrochloric acid and 5 ml of nitric acid in a covered 50 ml beaker on a boiling water bath for about 30 minutes. After cooling, the solution was filtered into a 100 ml calibrated flask and diluted to the mark with water. The atomic absorbance of each element in the sample solution was measured using an atomic absorption spectrometer using an air-acetylene flame.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 Appendix XV-1, pp. 318-337 of the related publication.