Borchert(1970)による〔『On the ore-deposition and geochemistry of manganese』(300p)から〕


The distribution of manganese in eruptive rocks has been elaborated together with A. Berger(1965). There are systematically higher MnO-values in intrusive rocks than in the corresponding extrusives with the same SiO2-content. Thus, negative values of “potential ore metal” are characteristic for manganese. Therefore, Mn is strongly concentrated in magmatic residual solutions, contrary to chromium and titanium which have positive values of potential ore metal, and which are concentrated in the very early products of fractional crystalization of basaltic magmas. Under fresh water conditions with low ion-concentrations, small asbolan deposits may be formed on peridotite-serpentinites (New Caledonia Type). Rich ore concentrations may be formed in connection with lateritic weathering, above all on the southern continents (old Gondwana Shield) on the basis of primarily poor protores. Special reaction processes of two groundwater masses may lead to the Lindener Mark Type in the southern part of the Rheinisches Schiefergebirge as well as to the big ore bodies of Postmasburg in South Africa. Under marine conditions with the development of a “carbonic-acid-zone”, manganese may be dissolved in solutions with much higher pH- and more positive Eh-values. Thus, the separation of Mn and Fe and of both from the main mass of Si-Al-components can take place. Pure manganese ore deposits of the Tschiaturi/Nikopol Type in an “expanded Black Sea” could thus be built up. On the other side, the “volcanic-sedimentary” type with shale-chert-spilite-manganese ore formation is strictly bound to residual solutions of basaltic provenance in an eugeosynclinal realm. The different genetic types are schematically demonstrated in Fig. 2. The physicochemical conditions for the separation of Mn and Fe are elucidated in Fig. 9.』

Distribution in igneous rocks and potential ore-deposit-forming manganese
Behaviour of manganese in residual melts and magmatic solutions
Manganese in superficial solutiona and under marine conditions
The geosynclinal shale-chert-spilite-manganese ore formation
Different genetic types of manganese ore deposits
Physicochemical principles involved in the separation of Mn and Fe