Bismuth and bismuth-antimony sulphosalts from Kutn\xc3\xa1 Hora vein Ag-Pb-Zn ore district, Czech Republic

[摘要] A new, previously unknown association of Ag-Pb-Bi-Sb sulphosalt minerals has been found in samples from mine dumps of the Staro\xc4\x8desk\xc3\xa9 p\xc3\xa1smo Lode of the Kutn\xc3\xa1 Hora Ag-Pb-Zn ore district, central Bohemia, Czech Republic. These minerals form polymineral aggregates up to 1-3 cm in quartz or base sulphides. Apart from numerous members of lillianite homologous series, new occurrences of aramayoite, bismuthinite, cosalite, ikunolite, izoklakeite, matildite, galenass, Bi-rich jamesonite, Bi-rich boulangerite, Bi-rich owyheeite and Bi-rich semseyite have been identified. An extraordinary extent of the Bi-Sb substitution is characteristic of the studied association. Bi-rich mineralization of this scope has not been previously known from the Kutn\xc3\xa1 Hora ore district.The origin of this sulphosalt mineralization is related to the penetration of lower temperature fluids (c. 100-250 °C) into tectonically opened fractures in older ore veins filling. Virtually no mobilization of elements from the earlier vein filling took place; hydrothermal fluids must have been relatively rich in Ag and Pb and simultaneously poor in Cu. High Bi content was characteristic of the initial stage of the mineralization. Gradually, the Bi/Sb ratio decreased considerably with more Sb-rich minerals originating. At the final stage, Bi-rich Pb-Sb sulphosalts with lower Ag contents crystallized.

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