『Abstract
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.』
Introduction
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
Conclusions
References