Palaeomagnetic and petromagnetic study of uranium-bearing polymetallic-fluorite mineralization in the Orlík-Kladsko crystalline complex (near Kletno, Lower Silesia, Poland)

Palaeomagnetic measurements of polymetallic-uranium ore in the Old Uranium Kletno Mine were carried out. Thermal and alternating field (AF) demagnetizations of the rocks studied (fluorite and quartz veins, cataclased gneisses, calcareous-silicate rocks with epidote/grossular) enabled isolation of two well-defined magnetization components. A normal polarity palaeomagnetic direction was preserved in magnetite and coarse hematite, whereas reversed polarity is linked with fine hematite grains. Both statistically well-defined components do not differ within limits of error. The calculated mean palaeomagnetic pole was compared with the European apparent polar wander path. This comparison points unambiguously, within limits of statistical error, for an Early Cretaceous to Paleogene age of characteristic components of magnetization. Consequently this age limit constrains the time of uranium-bearing polymetallic-fluorite mineralisation.