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The Kyzylalmasay epithermal Au-Ag deposit forms part of the Kuraminsky zone of the Beltau-Kurama volcano plutonic belt in the Western Tien-Shan. The orefield is confined to the intersection of the polygenic Shavaz-Dukent graben and the meridional Dukent-Gushsai deep fault. Host rocks of the Kyzylalmasay deposit are isolated block-horst uplifted Caledonian granitoids with xenoliths of Ordovician-Silurian slates and syenito-diorites and felsite dykes. Ores from underground have been investigated using a Jeol Superprobe JXA-8880R and Elan DRC II ICP mass spectrometer. The main productive mineral ore association is electrum-selenide-polysulphide with alloys, sulphides, sulphosalts, selenides and seleno-tellurides of silver which occur in micro- and nanomineral form and do not attain more than 50-100 μm in size. In the upper horizons, gold-silver mineralization occurs as native silver, kűstelite, allargentum, naumannite, aguilarite, Se-stephanite and polybasite. In deeper horizons of the deposit, of most abundance are acanthite and sternbergite, but also bohdanowiczite (AgBiSe2), cervelleite (Ag4TeS), hessite (Ag2Te), tsnigriite (Ag9SbTe3(S,Se)3)and various transitional compounds of the system Ag-Te-Se-S. Gold fineness attains.760-.770. In the deeper horizons, gold is characterized by increased concentrations of Hg (up to 2.05%) and Pt (up to 0.089%). Unnamed Ag3AuS2 (21.0 wt.% Au, 71.39 wt.%, Ag, 7.08 wt.%S, 0.54 wt.% Hg, 0.1+ wt.%Te) was first found here. Similar compounds have previously been identified in the hypogene zone of the Kochbulak Au-Te deposit. The deep horizons are characterized by increased numbers of sulphides and tellurides; the quantities of galena, arsenopyrite and chalcopyrite are also greater at depth. A vertical zonation from Au-Ag-Se to Au-Ag-Te mineralization is recognized, this appears typical for gold-silver mineralization of epithermal type.
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