Summaries of the transition element chemistry of oceanic ferro-manganese deposits report compositional trends related to water depth and to geographic proximity to continental margins1-4. Explanations of compositional variations include continental source influence3, 5, 6, diagenetic environmental control of manganese mineralogy that regulates the trace metal composition1, 3, 7, ionic mobility in interstitial solutions during diagenesis3, 8-10, and volcanic or hydrothermal influence3, 11-14. Glasby15 rejects a significant pressure control on manganese oxide mineralogy on thermodynamic grounds.

The entire sample was dissolved by a HCl-HNO3-HF treatment.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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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.

Supplement to: Scott, Robert B; Rona, Peter A; Butler, Louis W; Nalwalk, Andrew J; Scott, Martha R (1972): Manganese Crusts of the Atlantis Fracture Zone. (see erratum for this paper: Nature Phys. Sci. 242, 95, 1973), Nature Physical Science, 239(92), 77-79