Dark crusts and concretions on volcanic and calcareous rocks dredged from seamounts west of the Aeolian Islands, southern Tyrrhenian Sea, consists mainly of amorphous Fe-Mn hydroxides, with some goethite, todorokite, birnessite and clastic minerals. Chemically they consist of predominant Fe (up to 45%) and Mn (up to 12%), with significant amounts of Zn, Ni, Co and Cu. That the REE distribution patterns are similar to those of shallow Pacific derivation - from hydrothermal waters cognate or cycled through volcanic rocks of intermediate composition - is tentatively suggested.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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: Morten, L; Landini, F; Bocchi, G; Mottana, A; Brunfelt, Arild O (1980): Fe-Mn crusts from the southern Tyrrhenian Sea. Chemical Geology, 28, 261-278