Journal of

GEOsciences

  (Formerly Journal of the Czech Geological Society)

Original paper

Marko Bermanec, Nikita V. Chukanov, Dmitry A. Varlamov, Ana Rajačič, Simeon Jančev, Vera N. Ermolaeva

Sulfide anomaly related to cymrite-quartz schist of the Kalugeri area, Pelagonian massif, Republic of North Macedonia

Journal of Geosciences, volume 68 (2023), issue 4, 301 - 311

DOI: http://doi.org/10.3190/jgeosci.383

A specific feature of a major part of regional metamorphosed metasomatic ores of the Nežilovo area, Pelagonian massif, Republic of North Macedonia is the occurrence of chalcophile elements (Zn, Pb, Sb, Cu, and As) in oxides and oxysalts whereas sulfides and sulfosalts are absent. This paper describes anomalous sulfide-bearing mineral assemblage discovered in small, localized outcrops at the Kalugeri locality belonging to the Nežilovo group of ore occurrences. Based on the data on mineral assemblages and associations, a four stage model is proposed. Pressures of the first stage was estimated to be above 20 kbar using barometry on Ba-rich first generation of phengite and temperatures above 530 °C were estimated by Zr in rutile thermometer. During this stage, sulfide mineralization still occurs with crystallization of sphalerite and galena. In the second stage occurring above 500 °C and above 10 kbar, the first generation of cymrite crystallized showing that barium was present in the system in excess compared to sulfur. The third stage was dominated by Zn-rich phengite, baryte-anglesite solid solution and cerussite formation at temperatures between 500 and 350 °C and pressures between 7.1 and 4 kbar. The final stage of formation is characterized by crystallization of the second generation of cymrite below 350 °C. It is concluded that sulfide-free ores of the Nežilovo type could form as a result of transformation of initial sulfide ores at low-PT conditions and a high barium activity.