The characteristics of volatile components and alkaline metasomatism in main skarn-type iron deposits in China and their role in ore formation

Abstract

Skarns, ores and hydrothermally metasomatic rocks associated with some major skarn iron deposits in China contain abundant volatile components, such as F, Cl and H2O. Alkaline (sodic or potassic) metasomatism is obviously evident in the magmatic and other alumo-silicate wall rocks. They may serve as important ore-searching indicators. In this paper, the probable source of iron fluids, transport forms of iron and conditions of precipitation of magnetite are also discussed.From the studies of major skarn iron deposits in China, the authors hold that volatile components, such as F, Cl, H2O, etc., and alkaline (K, Na) metasomatism play a very important role in the formation of this type of iron deposits[1, 2, 3].