Žune Ba-F epithermal deposit Part 1: Mineralogical and geochemical characteristics

The Žune Ba-F epithermal deposit is situated in the Ljubija ore field (NW Bosnia and Herzegovina), within Upper Palaeozoic dolostone. A typical ESE-WNW Variscan vergency fault zone separates dolostone from Lower Triassic schists sandstones. External internal pseudo-bedding, with massive, homogenous structure partial limonitization characterizes Its geochemical composition exhibits low SiO2 (1.33 – 2.06 mass. %), Al2O3 (0.27 –0.38 BaO (0.02 0.83 ƩREE (5.7 9.4 ppm), Sr (61.7 120.4 Sm (0.3 2.2 ppm) Eu (0.1 0.6 while having high CaO (30.24 32.38 MgO (16.47 17.35 %) LOI (44.6 45.58 %). dolostone-mineralization contact consists of metasomatically recrystallised host quartz pyrite, where presence accessory tremolite, magnesiochloritoid pyknite indicates peak formation conditions pre-mineralization phase temperatures above 300°C. Two types are described: (i) vein-type mineralization composed barite fluorite ± quartz, (ii) hydrothermal breccia coarse-grained barite, surrounding fragments dolostone, occupying ≈20 % deposit. Mineralized samples show slightly elevated (2.20 5.53 (0.24 0.74 (below 0.02 3.1 (up to 50.74 66.03 (20 166 (exceeding 1 118 44 ppm). Elevated can be correlated other epigenetic deposits Dinarides, interpreted as BaSr substitution crystal lattice. Fluorite-rich characterized by Y (0.6 –49.2 HREE enrichment, accompanied depletion LREE. Žune, variable REE concentration a negative cerium ytterbium anomaly corresponds geochemically world-class associated carbonate sedimentary rocks.