Concretions of manganese have been discovered by the geological expedition to the islands of the Timor group in 1910—1912 in triassic and jurassic deep-sea deposits, on the Island of Timor, and also well developed in similar jurassic deposits on the island of Rotti, and previously, in 1894, the author noticed them in abysmal deposits of the pre-cretaceous probably jurassic Danau formation, occurring in West and East Borneo. On the island of Rotti nodules of manganese were found in several localities in siliceous limestones, marls, siliceous and calcareous clayshales along with concretions and nodules of chert of jurassic age, full of tests of radiolaria.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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: Molengraaff, G A F (1915): On the occurrence of nodules of manganese in mesozoic deep-sea deposits from Borneo, Timor, and Rotti, their significance and mode of formation. Koninklijke Nederlandse Akademie van Weteschappen (Proceedings of the Royal Netherlands Academy of Arts and Sciences,Series B Physical Sciences; http://www.dwc.knaw.nl/DL/publications/PU00012518.pdf, 18(15), 415-430