Bismuth minerals from the Stan Terg deposit (Trepça, Kosovo)
Kołodziejczyk, Joanna; Pršek, Jaroslav; Melfos, Vasilios; Voudouris, Panagiotis Ch.; Maliqi, Feriz; Kozub-Budzyń, Gabriela
published: Jul 1, 2015
ArtNo. ESP154019203006, Price: 29.00 €
The Bi-bearing sulfosalts and chalcogenides, ikunolite, babkinite, joséite-A, izoklakeite, cannizzarite, lillianite-gustavite and heyrovskýite, previously unknown in Kosovo, were identified in the Stan Terg deposit by means of electron microprobe analyses in samples from skarn and skarn-free mineral assemblages. Phase relationships among the minerals in the system Bi-Te-Pb-Ag-Cu indicate that they formed at different times with successive replacement of one mineral assemblage by the next, and do not represent decomposition products of high temperature Bi-bearing phases. The following replacement sequence is considered: lillianite/ gustavite+heyrovskýite+galena → izoklakeite-giessenite+cannizzarite → bismuthinite+native bismuth → bismuth chalcogenides (joséite-A, ikunolite, babkinite) → chalcopyrite. Ikunolite and babkinite show a low degree of S and Se substitution and higher content of Pb for Bi substitution, suggesting a potential ikunolite-babkinite solid solution. Joséite-A is the first tellurium mineral described from this locality. Lillianite homologues include lillianite (N = 4) and heyrovskýite (N = 7) of low degree of AgBi for 2Pb substitution and average substitution coefficients x = 0.21 and 0.17, respectively. Izoklakeite-giessenite from Stan Terg has an average Sb/(Sb+Bi) ratio of about 0.43. Other identified Bi-bearing minerals include cannizzarite, native bismuth, and bismuthinite. All described minerals are associated with galena with elevated Bi and Ag contents (0.02 Bi+Ag apfu). Native gold is spatially related with Bi mineralization. The bismuth-bearing phases at Stan Terg were formed during the retrograde evolution of the hydrothermal system under generally low-sulfidation and reduced fluid states in the temperature range from 350° to 250 °C.