Journal of

GEOsciences

  (Formerly Journal of the Czech Geological Society)

Original Paper

Krs, Stanislav Vrána

Palaeomagnetism and petromagnetism of augite microgranodiorite, Nezdice near Kasperske Hory, southern Bohemia

Journal of the Czech Geological Society, volume 38 (1993), issue 3-4, 201 - 207

A non-porphyritic augite microgranodiorite, forming several dykes intruded in the Varied Group of the Moldanubian Zone, has been studied. One dyke, several metres thick, exposed at Nezdice near Kašperské Hory, southern Bohemia, provided samples suitable for petromagnetic and palaeomagnetic investigations. The remanence was found of prevailing one-component nature, the principal carrier of magnetization and palaeomagnetization is pyrrhotite. Above the Curie point of pyrrhotite, in the temperature interval of 320-390 °C, a small component of remanence was found parallel to the direction of remanence of pyrrhotite, whose carrier is Ti-rich Fe-oxide. The derived palaeomagnetic pole position falls within the Carboniferous and Lower Permian pole positions so far derived on the territory of the Bohemian Massif, and most closely within the Lower Permian pole positions. The low unblocking temperature of pyrrhotite and the general trend of analyzed remanence components suggest interpretation of thermal and palaeotectonic stability of the region under investigation in the time span from the Lower Permian to the present time.