Browsing by Subject "autooxidation"

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Access status: Open Access ,
Badania genezy cechsztyńskich złóż miedzi w Polsce
(Wydawnictwa AGH, 2010) Kucha, Henryk; Pawlikowski, Maciej
Kupferschiefer Cu deposits were probably formed as a result of two brines mixing. The upper cold brine (UCB) was base metal-free but rich in Na, Ca, SO$_{4}$ and Cl with pH > 7 and originating from evaporates overlying the Cu deposits. The lower hot brine (LHB) was rich in Mg, K, Cl, SO$_{4}$, CO$_{2}$ and pH < 7 formed in the central part of the Polish Zechstein Basin at a depth of 6-7 km. The LHB was heated up to 200-250°C and was a subject of upward convection towards the Zechstein suboutcrops along the bottom of the Z1 carbonates. The mineralization process was a result of the mixing of the brines LHB and UCB, and catalytic autooxidation of organic matter of the black shale which operated at shallow depth of the Fore-Sudetic Monocline. The boundary of these brines generally overlapped the strike of the black shale. The presence of nests and veinlets of silvite (KCl), AgCl (chloargirite) and K-castaingite in the black shale bottom speaks in favor of the LHB existence. Parts of shale-free Cu deposits suggest that the action of two brines was capable of accumulation of economic Cu, Pb and Zn ore horizons. Where the boundary of brines overlaps the autooxidation zone (the black shale bottom) and also coincides with á and g radiation of thucholite concentrations of noble metals occur. The characteristic vertical distribution of the quadruplet hematite Cu Pb Zn from the bottom upwards is universal in the Kupferschiefer deposits.