Original paper
Tin deposits and the mantle
Shcheglov, A. D.
Global Tectonics and Metallogeny Volume 4 Number 1-2 (1991), p. 69 - 74
14 references
published: Jan 1, 1991
ArtNo. ESP136000401007, Price: 19.00 €
Abstract
The author reviews the data on the source of tin in magmatic processes and associated metallogeny, and distinguishes between crustal tin deposits and mantie tin deposits. The crustal tin deposits are represented by high-temperature quartz veins, tin-bearing greisens and pegmatites, and are characterized by a triad of ore minerals: cassiterite, wolframite (or, scheelite). and molybdenite. These deposits are associated with leucocratic, often pegmatoid two-mica granites, emplaced during the middle and late stages of miogeosynclinal evolution (Transbaikal region, Primorye, Rudny Altai). The mantle tin deposits display a number of specific features, in particular: Association with deep-seated fault zones, connection with processes of tectono-magmatic activation, block structure of the substrate, reduced thickness of the crust above uplifted blocks of the basaltic layer or mantle. Typical is a multi-stage development of these deposits. Ore minerals and tourmalines are characterized by a group of typochemical elements: Cr, Ti, Co, Ni and V. Molybdenum, so typical for crustal tin deposits, appears to be an antagonistic element for the mantle tin deposits. Detailed mineralogical and geochemical studies of several mantle tin deposits have revealed additional criteria indicating a subcrustal source of tin. For instance, cassiterites from some deposits of Primorye contain, according to Osipova (1986), very fine inclusions of chromite, ilmenite, rutile and anatase. The analyses of these inclusions show similarities to chromites from dunites of some Ural Mts. deposits. The tourmalines from the Komsomolsk and Kavalerovo ore areas in the Far East, presumably associated with a mantle source, contain, according to Gorelikova (1981), elevated concentrations of Cr, V, Ni, Ti and Mn, while tourmalines from deposits of the cassiterite -pegmatite formation are known to have a different association of microelements: Ta, Nb, Sc, Ga, Sn and Ba.