Stable isotope (δD, δ18O) data on the structural water of two sericite samples from the Cu-Au high-sulphidation deposit Chelopech, Bulgaria – a tentative study

The epithermal high-sulphidation Cu-Au Chelopech deposit is characterized by a well-developed and well-traceable hydrothermal footprint manifested in the volcanic host rocks. economic ore mineralization embedded strong silicification, included among advanced argillic zone of alteration, smoothly transitioning to quartz-sericite alteration that evolves into widespread propylitics. accessible for exploration only underground mining galleries drillings. main mineral assemblage this quartz, sericite, pyrite, minor rutile/anatase relics apatite feldspar. According XRD data from studied samples, sericite was defined as illite muscovite/sericite 2M1 polytype. abundance heavy stable isotopes (D, 18O) structural water two samples object study. A special attention paid separation extraneous waters one thermal fractionation. extracted converted hydrogen carbon dioxide before isotopic measurements. obtained results, put δD vs. δ18O plot, indicate “heavier” than meteoric water, within uncertainty limits.