In the mid 1970s Kennecott Exploration, Inc. conducted various systematic studies on the chemical composition of manganese nodules and crusts in order to determine the variability of their composition. They ultimately prepared a "normalised" manganese sample numbered GRLD-126 (see: Meylan, Maurice A (2022): Kennecott Standard GRLD-126 manganese nodule replicate Atomic absorption spectrophotometry (AAS) analyses, https://doi.pangaea.de/10.1594/PANGAEA.948422). The present dataset compiled by NOAA-NCEI is devoted to the extensive analysis of mostly buried in cores manganese deposits recovered by the R/V Robert Conrad and the R/V Vema from the Lamont-Doherty Earth Observatory (LDEO). Samples were analysed by the atomic absorption spectrophotometry by Kennecott Exploration, Inc.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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.