Terrane character of the north-east margin of the Moldanubian Zone: the Kutn� Hora Crystalline Complex, Bohemian Massif

Abstract

Three major allochthonous units have been distinguished on the north-eastern border of the Moldanubian Zone, which differ each from other in lithology and structural and metamorphic evolution. Their present day position displays significant metamorphic and structural inversion resulting from progressive nappe stacking during the Variscan orogeny. The uppermost-Gfohl Unit consists of anatectic rocks containing high temperature/high pressure relics, i.e. granulites, eclogites and garnet peridotites. The rocks of the Gfohl Unit were strongly mylonized during uplift and later also extensively migmatized in the kyanite stability field. The Kouiřim Nappe is built up by a sequence of fine-grained leucocratic migmatites with preserved relics of a pre-Variscan deformation event. This event was terminated by the intrusion of coarse-grained porphyritic granites, converted into augen orthogneisses by the Variscan orogeny. The lowermost Micaschist Zone was formed from a sequence of metapelites intercalated with diopsidic amphibolites.