Metallogenesis and Tectonics of the Russian Far East, Alaska, and ...

Yaroslavka Sn Greisen Deposit
The major Yaroslavka Sn greisen deposit (fig. 20) (Govorov, 1977; Ryazantzeva, 1998) occurs mainly in greisen which
mainly replaces skam, limestone, and schist; and to lesser extent in granite and granite porphyry witb a Rb-Sr isotopic age of 408
Ma and an initial Sr ratio of 0.7 136 (Rayazantseva and others, 1994). Tln-bearing quartz and quartz-tourmaline veins, related to
replacement of skarn by greisen, are classified into: (1) mineralized fracture zones; (2) ore veins; (3) veinlets and ore pods; and (4)
saddle-shaped and sheeted ore. The Sn ores are classified into three types based on mineral associations: (1) tomalinequartz; (2)
tourmaline-fluorite; and (3) sulfide-tourmaline-quartz with subordnate cassiterite-polymetallic a d chlorite-sulfides. The sulfide
minerals are dominantly pyriie, arsenopyrite, galena, and sphalerite. The deposit occurs along the conhct of a early Paleozoic
biotite granite (approximately 400 Ma) which intrudes Early Cambrian shale, siltstone, sandstone, end limestone. The pre-ore
pyroxex-scapolite, vesuvianite-garnet, and epidote-amphibole skarn occurs in limestone and shale dong the granite contacts, and
in rare limestone inclusions within the granite. The deposit is of medium size. The average grade is 0.52% Sn. The deposit was
mined h the 1950's through the 1970's. Over forty occurrences of and vein deposits are known in the Yaroslavka metallogenic
belt.
roslavka Sn greisen deposit, Yaroslavka metallogenic belt, Russian Southeast. Schematic geologic n
(1 977) and Ryazantzeva (1 998).
Adapted