Mineralogy of W-Pb-Bi ores from Rudnik Mt., Serbia

摘要

Polymetallic W-Pb-Bi ores have been found in the Nova jama ore zone of Rudnik Mt., Serbia. They are situated on the contact of quartzlatite dykes and breccias; mostly occur in a stockwork-type form. In this ore zone three mineralization phases can be distinguished: pyrometasomatic (skarn), pyrometasomatic-hydrothermal and hydrothermal. The pyrometasomatic-hydrothermal phase is the most significant mineralization phase because it is represented by massive ore bodies. They contain a wide variety of minerals including significant amounts of scheelite, native bismuth and sulphosalts, mostly presented by Pb-Bi-sulphosalts. Mo-free scheelite, the only tungsten bearing mineral, was found in economically interesting amounts. Energy Dispersive Spectrometry (EDS) analyses yielded the empirical formulae: Ca_(0.98)WO_4 for scheelite, Pb_(0.99)S for galena, (Pb_(1.91)Ag_(0.05)Cu_(0.08))_(2.04)Bi_(1.93)S_5 for cosalite and (Pb_(0.98)Ag_(0.03)Cu_(0.05))_(1.06)Bi_(1.99)S_4 for galenobismutite. Tetragonal unit-cell parameters for scheelite amount to a = 5.24291(6), c = 11.3738(2) A, V= 312.644(7) A~3. Atomic coordinates, isotropic displacement parameters, interatomic distances, and angles of scheelite were refined from X-ray powder diffraction data using the Rietveld method. Orthorhombic unit-cell parameters were calculated from single crystal data for cosalite to a = 19.13(1), b = 23.64(5), c = 4.070(3) A, V= 1839(5) A~3 and for galenobismutite to a = 11.743(3), b = 14.525 (8), c = 4.087(8) A,V= 696.0(7) A~3.