The study of lake deposits containing iron-manganese nodules is of significant interest for the understanding of one of the continental manganese and iron concentration processes. In the USSR, much attention has been given to the formation conditions of ore accumulations in the Leningrad region and Karelia. Semenovich came to the conclusion that Fe super(+3) and Mn super(+4) entered the lake during a long period of drought and were buried together with organic matter of plant origin. In the lake muds, manganese and iron are reduced; readily soluble compounds of Fe super(+2) and Mn super(+2) are transported by bottom waters. Oxidation of iron and manganese to Fe super(+3) and Mn super(+4) occurs, precipitating oxides on the bottom that form nodules and incrustations. This scheme of lacustrine ore genesis by the accumulation of manganese and iron is well founded.

Elevation 2 = Altitude.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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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: Chukhrov, F V; Gorshkov, A I; Berezovskaya, V V; Sivtsov, Alexander V (2010): Mineralogy of lake ores. International Geology Review, 25(7), 833-847