Tungstates of the Boyovskoye tungsten deposit (Southern Urals)

Abstract

The relevance of the work is due to the need for a mineralogical study of tungsten deposits in the Ural region, which have been mined since the end of the 19th century. The purpose of the work is the diagnostics and detailed description of tungstates from the Boyovskoye tungsten deposit located on the border of the Chelyabinsk and Sverdlovsk regions in the Southern Urals. Analytical studies were carried out in the Laboratory of Physical and Chemical Research Methods of the Institute of Geology and Geochemistry, UB RAS, Ekaterinburg. The chemical composition of minerals was analyzed in polished sections on a CAMECA SX 100 microanalyzer. Measurement conditions: accelerating voltage 15 kV, current 150 nA, electron beam diameter 2 μm. The pressure in the sample chamber is 2 ⋅ 10–4 Pa. The spectra were obtained on tilted wave spectrometers; the intensity was measured from analytical lines. Standard samples: scheelite, wolframite, galena, rutile and chromite. Raman spectra of minerals were obtained using a LabRam HR Evolution spectrometer (Horiba Scientific). A red laser, 532 nm, was used for analysis. As a result of the work, new data on the chemical composition of hubnerite and scheelite were obtained and their Raman spectra were presented. For the first time for the Boyovskoye tungsten deposit, a reliable diagnosis and description of lead tungstate – stolzite was made. The mineral was found in samples with veined quartz in association with muscovite, fluorite, hubnerite and scheelite. It fills cracks and voids in hubnerite, rarely overgrows scheelite or fills cracks in scheelite. It is a later mineral in relation to hubnerite and scheelite. Its chemical composition contains impurities of manganese, calcium, iron and titanium. The stolzite found by us is a mineral of the oxidation zone and, most likely, was formed due to the weathering of wolframite and galena, which is also present in quartz veins.