The results based on the study of 25 wolframite deposits from the USSR, Mongolia and Czechoslovakia allow to analyze the relations between temperature, pressure, composition of solutions and wolframite composition. According to these analyses, the deposition of wolframites varying in composition from hübnerite to ferberite occurred in the temperature range 410-260 °C under pressure conditions within the range 700-1 700 bars. These results suggest that wolframite composition does not depend on temperature and pressure and thus can not be used as a geothermometer or a geobarometer. The chemical composition of wolframites and iron-manganese-bearing minerals associated with wolframites of 7 tungsten deposits was also investigated. The corresponding changes of the Mn/Fe ratio in the associated minerals (wolframite-rhodochrosite-triplite-sphalerite) was determined. According to the experimental studies on the distribution coefficients of Mn and Fe between wolframite, sphalerite and solution, the wolframite composition reflects the Mn/Fe ratio in the coexisting hydrothermal solutions. Scheelites of various genetical types of deposits formed in a wide temperature range (600-120 °C) under pressure conditions varying from 1 650 to 300 bars from two types of solutions with high and low salinity, 75-30 and 15-2 wt.% eq. NaCl, respectively.

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