Assyntyjskie założenia tektoniczne żył kwarcowych o kierunku NW-SE w okolicy Barcinka

Abstract

ASSYNTIC TECTONIC NATURE OF NW-SE TRENDING QUARTZ VEINS FOUND IN THE VICINITY OF BARCINEK

Summary

Quartz veins characterized by a NW-SE direction, found to occur in the vicinity of Barcinek, near Jelenia Góra, Pogórze Izerskie area (Lower Silesia), contain autochthonous inclusions represented by mica schists, laminated gneisses, lenticular gneisses and gneissose granites. Spatial orientation of foliation plane within the autochthonous inclusions here considered is NW-SE, showing a changing dip from SW to NE (Fig. 1). In addition to the direction mentioned above there is also another spatial orientation of foliation plane, seen on Fig. 2. Linear structures in the rocks of the autochthonous inclusions and in the vein selvages are anastomosing feldspar-quartz intergrowths, linear arrangement of laminar minerals (biotite, muscovite and sericite), quartz aggregates, and linear elongations of feldspars. The above directions of B-elongation are presented in Figs. 3 and 6. Beside the parakinematic lineations mentioned before, other lineations are also found to occur in the inclusions considered. Quartz veins appear in the cores of Young Assyntic slices produced as a result of the rebuilding process of Old Assyntic folds due to the compression directed southwards. At places, the slice zone bears features of shearing zones. At the time of the younger movements, the tectonic zone considered was rejuvenated, thus the accumulated quartz is here of several generations