mineral deposits arising in the process of the cooling and crystallization of basic magma containing sulfurous compounds of metals.
In the process there occurred the separation (or liquation) of the cooling melt into two immiscible liquids—liquid silicate and sulfide. As the silicate melt hardened, magmatic rock of a gab-bro-peridotite composition was formed, and as the sulfide melt crystallized, deposits of sulfide ores were formed. Such deposits are concentrated near the bottom part of the dish-shaped masses of related magmatic rock, penetrating from there in the form of intersecting ore bodies into both the upper parts of the masses as well as the underlying sedimentary rock. Sulfide copper-nickel liquation deposits are the most characteristic. The chief components in the ores from these deposits are pyrrhotite, pentlandite, and chalcopyrite, while magnetite, cobalt minerals, and platinoids are present in smaller quantities. The ores have a massive and impregnated structure. Among the sulfide copper-nickel liquation deposits there are very large and rich deposits that are an important source of copper, nickel, cobalt, and platinoids (for example, the deposits of Noril’sk, Talnakh, and Pechenga in the USSR and Sudbury in Canada).
REFERENCESGodlevskii, M. N. “Magmaticheskie mestorozhdeniia.” In Genezis endogennykh rudnykh mestorozhdenii. Moscow, 1968.
Smirnov, V. I. Geologiia poleznykh iskopaemykh, 2nd ed. Moscow, 1969.
V. I. SMIRNOV