Synfolding calcite veins in the Holy Cross Mountains Fold Belt, central Poland

Abstract

Bedding-parallel calcite veins in Devonian rocks from the southern part of the Holy Cross Mountains Fold Belt in central Poland occur as tabular bodies on shallow dipping as well as vertical Late Paleozoic map-scale and mesoscopic fold limbs. The syntaxial and antitaxial bedding parallel veins contain kinematic indicators such as rotated blocks, fibre boundary steps, boudin trains, beef-like structures and congruous steps. These structures show a sense of movement consistent with the flexural slip typical of folding resulting from buckling during layer-parallel shortening. We propose the mechanism of the gradual formation of the veins and the progression of fabric development which is mostly consistent with an increasing dip angle of the fold limbs and their gradual deformation. Textures of the veins and kinematic indicators within the veins point to the syntectonic growth of calcite during the Late Paleozoic buckle folding in the Holy Cross Mountains Fold Belt.