Abstract
Unusual W-bearing complex Mn-Ti-oxide-hydroxides were found in the carbon-bearing breccia-like aggregate from the gold-bearing skarn of the Makmal deposit (Central Tyan-Shan, Kirghizstan). These are amorphous chemically individualized compounds with the general formula:
Me2+2x(Ti, W)4-xO4-X(O, OH, H2O)12+x, where Me=(Mn, Mg, Ca, Fe)2+, 0≤x≤l. Mg-Mn-Ti-and Ca-Mn-Ti-variet-ies may be distinguished. They contain up to 5 mass % W. Incoming of W into TiO6-polyhedra was supposed.
Mn-Ti-oxides are associated mainly with calcite, serpentine, geikielite, Ti dioxides, pyrrhotite. Their deposition connected with the end of polysulphide or the beginning of gold-sulphosalt stages of mineralization. Possible causes of Mn-Ti-oxides formation are oxidation and decrease in temperature of circulating aqueous fluid which leads to the hydrolysis of migrational Mn, W, and other ore elements compounds.
