A geochemical (major and trace elements including rare earths) study was made of core samples drilled between the Touamotou Archipelago and the Marqueses Islands during the COPANO campaign (R/V Le Noroit). The samples consisted of cores of surface sediment and a large flattened nodule with an indurated nucleus. In one of the cores, the comosition of manganese micronodules was also udertaken. The geochemical determination of most of the major and trace constituants has been by direct-reading arc spectrometry. Na and K have been measured by optical emission spectroscopy. Samples were first dessicated at 110°C before analysis. Loss on ignition was also determined at 1000°C.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 2,4 and 5, pp. 119,120 and 123 of the related publication.