Basal sediments cored above alkali basalt at Site 183 beneath the Aleutian Abyssal Plain include iron-rich clays, a geothite-bearing calcareous ironstone (23.8% Fe and 4.16% Mn, CaCO3-free), and a pyrite-bearing unfossiliferous aragonitic limestone with 1.95 per cent Sr. At Hole 192A, atop Meiji Guyot, the northernmost of the Emperor Seamounts, five meters of iron and manganese-enriched clays interlayered and diluted with chalk lie on extrusive alkali basalt pillow lavas beneath almost a kilometer of silts, clays, and diatomaceous oozes.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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: Natland, James H (1973): Basal Ferromanganoan Sediments at DSDP Site 183, Aleutian Abyssal Plain, and Site 192, Meiji Guyot, Northwest Pacific, Leg 19. In: Creager, J.S.; Scholl, D.W.; et al., Initial Reports of the Deep Sea Drilling Project, Initial Reports of the Deep Sea Drilling Project, U.S. Government Printing Office, XIX, 629-636