Petrografie a geochemie amfibolitů strážovského moldanubika

Abstract

The amphibolites from the Strážov Moldanubian unit in western part of the Bohemian Massif form intercalations in metasediments of this geological unit. The Strážov Moldanubian unit forms the westernmost occurrence of Variegated group of the Moldanubian Zone. These amphibolites occur as intercalations of very different size in biotite-sillimanite, partly migmatitized paragneisses. The amphibolites were sampled in two abandoned quarries near the Svatá Kateřina and Běšiny. According to their modal composition the amphibolites occurring in quarry Radošín, near the Svatá Kateřina village, are plagioclase-bearing amphibolites with very high differences in amphibole and plagioclase ratio. The garnet is significant minor component of some amphibolites. The amphibolites occurring near of the Běšiny village form very thin, relatively long lenses as part of calc-silicate-amphibolite stromatites occurring in the central part of the Strážov Moldanubian unit. The both amphibolites are probably a metamorphic equivalent of tholeiitic volcanic rocks with tectonomagmatic features of the middle ocean ridge basalts (MORB).