Volcanic rocks dredged from the tops of seamounts in the Line Islands and cored from their flanks demonstrate that this is a region of extreme petrologic diversity. Tholeiitic and alkalic basalts were obtained in a single dredge haul and a wide spectrum of alkalic differentiates, including quartz trachytes, and phonolites were dredged or cored elsewhere. Four dredge stations on widely scattered seamounts recovered potassic nephelinites, unlike any other volcanic rocks heretofore found in the ocean basins. These rocks include amphibole and biotite-bearing varieties, some of which are leucite normative.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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 (1976): Petrology of Volcanic Rocks Dredged from Seamounts in the Line Islands. In: Schlanger, S.O.; Jackson, E.D.; et al., Initial Reports of the Deep Sea Drilling Project, U.S. Government Printing Office, XXXIII, 749-777