Chapter 4 - The Major Epochs and Phases of Manganese Accumulation in the Earth’s History

Abstract

The sedimentation of manganese rocks and ores took place over the course of practically the entire geological history of the formation of the Earth’s upper crust. But formation of manganese ores and deposits only occurred episodically. Epochs and periods of manganese accumulation based on the resources of this metal contained in rocks of a given age: Archaean, 3500–2500 million years; Proterozoic, 2500–550 million years (epochs: Early-Middle Proterozoic, 2500–1000 million years and Late Proterozoic (Neoproterozoic), 1000–550 million years); and Phanerozoic (epochs: Early-Middle Paleozoic (Cm-D), Late Paleozoic (C-P), and Mezo-Cenozoic (T-Pg). The industrially most important is the early Proterozoic period. At this time, the South African (the Kalahari manganese ore field), Gabon (Franceville basin deposits), Ghana, Brazil, India, etc. deposits were formed, which encompass at least 70% of land reserves of manganese. In this chapter was considered the basic regularity of the evolution of manganese ore formation in the history of the Earth. For the different geological times in the contours of previously existing paleocontinents (Ur, Baltica, Gondwana, Rodinia, Pangea, etc.) regions and paleobasins of manganese-ore accumulation were delineated. With the change of tectonic and volcanic activity and position of manganese-ore basins changed also the type of the processes of manganese ore genesis; accumulation of manganese has been linked with both hydrothermal-sedimentary processes, and the processes of diagenesis in marine clastic and carbonate-terrigenous sediments, often associated with carbonaceous shales. The formation of manganese rocks and ores on many geological boundaries was closely connected with global climatic and tectonic restructurings (the breakup of continents, periods of glaciation and aridification) as well as biological events (mass extinctions of organisms on some geological boundaries, eg, those of the Devonian and Carboniferous, Permian and Triassic, Cretaceous and Paleogene, and other stratigraphic levels).