CONDITIONS OF FORMATION OF FERROMANGANESE NODULES IN THE BOTTOM SEDIMENTS OF LAKES IN THE BALTIC SHIELD

Abstract

The water basins in the bottom sediments (BS) of which ferromanganese nodules (FMN) are formed have long drawn close attention of researchers, mostly as sources of iron ore for the mining industry. Such ore occurrences are relatively widespread in various regions of the ocean and continental freshwater basins, including Lake Baikal, Lake Onega, and many small lakes in northwestern Russia. Thematic studies by the Institute of Geography, Academy of Sciences of the USSR showed that ferromanganese mineralization in lacustrine BS is common in the Baltic shield, both in Karelia and in the Kola Peninsula. In the latter case, the mineralization is mainly confined to deep lakes, and the largest ore occurrences occur in the upper mud levels of deep-water areas.