(Table 2, page 132-133) Chemical composition of the soluble fraction of oxidate portions of Lakes Shebadnowan ferromanganese concretions

Samples were digested in 50% HCl at 95°C for about 45 minutes. The insoluble fraction was filtered off and the residue was ignited for 15 minutes 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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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.