Origin of stratiform lead-zinc deposits / Происхождение стратиформных свинцово-цинковых месторождений

The stratiform deposits make up a special group of lead-zinc deposits possessing many common features in which they differ from the similar deposits of other industrial-genetic types.
They are characterized by ores confined to strata of carbonate rocks, most frequently dolomites, by ore bodies of predominantly stratal form represented by impregnation ores of simple mineral composition, within which galena usually predominates over sphalerite (rarely the reverse), by the absence of magmatic rocks of similar age to the ore in the vicinity of the deposits, by the substantial proportion of carbonates, barite and fluorite among the vein minerals, and often by increased contents of germanium and thallium. The deposits of this type include those of the Tri- state area, and the states of Kentucky, Illinois and others in the USA, the Pine Point deposit in Canada, the Upper Silesian deposits in Poland, and the Mirgalim say, Achisay, Sumsar, Uch-Kulach and other deposits in the Soviet Union. This type of lead-zinc deposits is of great economic importance: about 30% of all the leadzinc ores extracted in the capitalist countries comes from stratiform deposits. <...>