The vast extent of pelagic deposits, covering about 70 per cent of the ocean floor, thus about half of the earth, makes them of obvious importance to all Earth Science. All the pelagic (eupelagic) sediments, whether largely of plankton remains or fine inorganic particles, have certain distinctive characteristics to reflect their environment of accumulation. The great segregation of manganese in pelagic sediments presents many problems. It is hypothesized that in the formation of present day nodules a relatively slow accumulation in order to permit deposition of more of the manganese as large nodules, rather than as the disseminated micronodules that are in larger proportion in the Tertiary.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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: Bramlette, M (1961): Pelagic sediments. in: Invited Lectures Presented at the International Oceanographic Congress Held in New York, 31 August-12 September 1959. Presented at the International Oceanographic Congress, 1959, American Association for the Advancement of Science, New York, U.S.A., 345-366