The chemical composition of sediments at various levels inside core 710KH also show a clear distinction between the overlying calcareous, siliceous-bearing to siliceous-rich muds and the underlaying dark brown clay. In particular, the dark brown clay is characterized by significantly higher contents of Mn, Fe, Co, Ni, Cu, Zn, Mg and P and lower contents of Ca and Ba than the overlying sediments. This distribution of elements probably reflects the presence of abundant micronodules, a lower content of barite and an almost complete absence of carbonate tests in the dark brown clays. The P content of the dark brown clays is higher than that of other typical deep-sea sediments from the equatorial N. Pacific or the SW Pacific. The organic-carbon content of the sediments is generally low and decreases from 0.3 to 0.1% with depth in the core.
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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 I (pp. 229) of the related publication.