Dolování stříbra v Zubří u Rožnova pod Radhoštěm ve světle legend, historických pramenů a nových geologických výzkumů

Abstract

Several historical sources mention silver mining in Zubří village near Rožnov pod Radhoštěm town in the first half of the 16th century. Critical analysis of these sources, new field observations, stratigraphic and mineralogical evaluation of the rocks were carried out to decide whether mining or prospecting for silver can have a real basis. Historical sources from the 18th and 19th centuries are likely to draw uncritically on popular folk tales and reports of fraudulent prospectors. This is evidenced by contradictions in the location of supposed mining, references to fictitious persons and unrealistic descriptions of mine workings. New field observations in Zubří brought improved knowledge of local geology. Clays and claystones from occasional excavations, soundings and outcrops were stratigraphically classified based on foraminiferal micropaleontology. The study area is built of Hauterivian to Paleocene strata of the Silesian Unit of the Carpathian Flysch Belt. At the site marked on the historical map as a former silver mine, no minerals containing Ag and Pb were found. Framboidal pyrite and traces of sphalerite of diagenetic origin were detected using SEM and microprobe method in the sandy limestone intercalation within the Lhoty Formation. The silt from the colluvial clay in the lower part of the site contained dominantly garnets close to almandine, minerals from the TiO2 group and Fe-oxides. Chemical analysis of colluvial clay showed heavy-metal (Ag, Cu, Mo, Zn, Pb) concentrations close to background values. These negative results are consistent with the sceptical conclusions from the analysis of historical sources. The only historical mine observed in the studied area is revealed by an old heap above the road to Staré Zubří. It is undoubtedly related to the mining of pelosiderite. The pelosiderite is abundant in places in the claystones of the Hradiště Formation on Stříbrník and in the Olšovec stream. This source was probably exploited in the first half of the 18th century for the local iron hammer.