40Ar/39Ar incremental heating experiments on three samples dredged from Jingu Seamount indicate that Jingu is 55.4 ± 0.9 m.y. old — older than the Hawaiian-Emperor bend and younger than the two dated Emperor Seamounts to the north. Major-oxide chemistry and petrography show that the samples are similar to hawaiites and mugearites from the Hawaiian Islands. By analogy with Hawaiian alkalic volcanic rocks, groundmass plagioclase compositions (An40-47) indicate that the three Jingu samples are probably mugearites. These results suggest that Jingu is a Hawaiian-type volcano and that the Emperor volcanoes become progressively older from south to north, as predicted by the hot-spot hypothesis.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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: Dalrymple, G Brent; Garcia, M O (1980): Age and Chemistry of Volcanic Rocks Dredged from JingƄ Seamount, Emperor Seamount Chain. In: Jackson, E.D.; Koisumi, I.; et al., Initial Reports of the Deep Sea Drilling Project, U.S. Government Printing Office, LV, 685-693