Genesis of Mineral-Forming Fluids of the Svetloe Deposit,Chukotka,Russia: Oxygen and Hydrogen Isotopic Data

摘要

The oxygen and hydrogen isotopic compositions of minerals precipitated at the premineral, productive, and postmineral stages of mineral formation at the Sn-W Svetloe deposit were studied. The isotopic composition of fluid was calculated from those of muscovite, quartz,wolframite,cassiterite,and calcite. it was shown that the hydrogen isotopic composition ranged between -119 and -132‰, which is similar to the isotopic composition of meteoric waters. The oxygen isotopic composition of fluids ranges within 2-10‰ (SMOW) with the predominant values within 4-6‰. The isotopic data were interpreted by mathematical modeling. Curves of the temporal evolution of magmatic and meteoric fluids were calculated. The comparison of experimental and calculated data indicates that the fluid of the productive stage was dominated by altered meteoric waters. It is assumed that the deposit was formed in the apical zone of a granite stock through mixing of magmatic solutions with large amounts of meteoric waters.