0393-000066 The forming conditions of Alyaskitovoe tin-tungsten deposit, Russia Corresponding author: Elena Anikina, IGEM RAS,
[email protected] Co-authors: Gennady Gamyanin, IGEM RAS,
[email protected] The Alyaskitovoe Sn-W deposit is located at the boundary between the Kular-Nersko terrane and the Verkhoyansk fold-thrust belt. It is localized in the tin-tungsten sublatitudinal metallogenic zone. The deposit area is composed of Upper Triassic sandstone-shale intruded by granite porphyry stock (98 MA Rb-Sr). Stock refers to the formation of young Li-F granites (P2O5 = 0.22- 0.56%, F = 0.12-0.21%, Sr = 9224-688g/t, Li = 47-252g/t, Rb = 61-194g/t). Stock and enclosing hornfels dissected by series of steeply dipping quartz veins meridional strike (L = up to 700 m, M = 0.4-0.6 m). Veins are accompanied by wallrock changes. It is greisenization in granitoids (up to 3 m) and tourmalinization – in hornfels (0.5 m). Several paragenetic associations are identified. Metasomatic: molybdenite-apatite1-tourmaline1- quartz-muscovite, tourmaline2-apatite2-fluorite-arsenopyrite-hydromica. Ore: cassiterite- wolframite-tourmaline-arsenopyrite-quartz, pyrrhotite-stannite-sphalerite-pyrite, molybdenite- matildite-aramayoite-galena-(Bi-andorite) Sb-gustovite, hubnerite-Ag-sulfoantimonite-calcite- quartz. Fluid inclusions (FI) in quartz of greisen and ore veins were studied. Temperature of homogenization of greisen inclusions is 460-480°C. FI contain weakly concentrated solutions (4.9- 3.3 wt.% NaCl-equiv), the gas phase is presented СО2 (29.6-78,2 mol.%), СН4 (11.1-21.8 mol.%). FI in quartz of ore veins contain a liquid phase with concentration 9.2-3.3 wt.% NaCl-equiv and homogenization temperatures of 290-380°С.