Geology, geochemistry and isotope characteristics of Balya (Balikesir) Pb-Zn deposit

Balya Pb-Zn deposit remains in southeastern part of Biga Peninsula, which is situated in 50 km NW Balikesir city. The basement rocks of the study area are represented with Permian aged limestones of Çamlıca formation and Triasic aged rock units of Karakaya formation which defined by mudstone and phyllate (Nilüfer unit), siltstone and sandstone (Hodul unit), and pebble and conglomerate (Orhanlar greywacke), carrying fingerprints of low grade regional metamorphism. Permian aged limestone blocks are observed as allochtonous in the rock units of Karakaya formation. The basement rocks have been cut and overlain by Oligo-Miocene aged dacitic lava, tuff and pyroclastic rocks of Doyuran volcanics and Upper Miocene aged andesitic dike, lava and agglomerates of Hallaçlar volcanics. (1) Serizite-quartz-pyrite and (2) advanced argillic alterations have been defined as regional alterations rich in clay and sericite, which are not directly related to mineralizations. (1) Early-stage (prograde calc-silicate) alterations and (2) late-stage alterations have been described as alterations that can be established temporal-spatial relations with the Balya Pb-Zn mineralisations and the Cu-Au mineralizations that have become economically viable in recent years. Late-stage alterations have been subdivided into temporally and spatially consecutive three sub-stages which are actinolite-epidote 1-chlorite-quartz 1), (b) moderate arijic and (c) late retrograde (epidote 2-calcite-quartz 2) alterations. Correlations of Pb, Zn, Ag,Cu, Au, Sb, Hg and As elements which are gained from geochemical analyses of systemically taken soil samples which are almost 40 km2 around of Balya Mine; correlations between Ag and Te elements with Pb; S,B, Bi and Sn elements with Zn; Pb, Te and W elements with Ag; and finally K, Rb, In, Bi elements with Cu have been verified. The positive correlation between As and Fe elements is result of ore mineral parageneses as arsenopyrite-pyrhotine, pyrite and even magneite-hematite those are showing temporal and spatial relationships which are differing due to mineralization style. δ34S values of galena, sphalerite and pyrites range from 1,5 ‰ to 3,9 ‰. The distribution of isotopic values exhibit a narrow range near zero. δ18O values obtained from quartz and calcite minerals vary between 12,7 ‰ and 16,6 ‰. Ore-alteration-wall rock relations, mineral assemblages of the alteration zone, the temporal and spatial distribution of the alteration zones and limited isotope data point out an intermediate sulfidation epithermal system containing skarn alterations (calc-silicate alterations) rather than Pb-Zn skarn type mineralization for Balya Pb-Zn Deposit. Keywords: Biga Peninsula, Balya, Pb-Zn deposit, Skarn, Epithermal