Ferromanganese deposits types

In this chapter, we have attempted to relate current ideas on the roles of microorganisms to the genesis of two very different types of iron deposits — one very ancient (Precambrian BIF s) and one modem (ferromanganese nodules and crusts) one comprising the most extensive resource of iron ore on land, and the other comprising the most extensive mineral deposit in the oceans. We can conclude that organisms were almost certainly involved, directly or indirectly, in the formation of both types of deposits, but exactly how and to what extent they are involved remain unanswered questions even for modem deposits. 

Shallow-water continental margin ferromanganese concretions have been reported in a number of areas such as the Baltic Sea, Black Sea, Kara Sea, Loch Fy ne, Scotland, and Jervis Inlet, British Columbia (Calvert and Price 1977). In fact, these were the first type of marine Mn deposits to be discovered, during the 1868 Sofia expedition to the Kara Sea led by A.E. Norden-skioldfEamey 1990). 

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