Rozważania geologiczno-strukturalne nad genezą deformacji glacitektonicznych
Abstract
Considerations on the origin of glaciotectonic stuctures
For a structural geologist, the following features of glaciotectonic deformations merit attention in the first place: their nature of classical tectonic structures, predominance of contraction structures, variable tectonic style not always correlated with lithology, multiple occurrence of structures, their vertical extent often greater than 100 m, and mostly vergent form usually facing the distal direction. The main conceptions on the origin of glaciotectonic disturbances, which have been applied for the area of Poland, do not explain sufficiently those features. In view of great diversity of operating factors, a universal model for glaciotectonics can hardly be constructed. However, many of the cases are explainable in terms of the "static-kinematic conception" proposed in this paper. It is based on the process of cylindrical shearing under prevailing static load, with a good part played by high pore pressure, anisotropy of the medium and its dilatant response to the strain.
For a structural geologist, the following features of glaciotectonic deformations merit attention in the first place: their nature of classical tectonic structures, predominance of contraction structures, variable tectonic style not always correlated with lithology, multiple occurrence of structures, their vertical extent often greater than 100 m, and mostly vergent form usually facing the distal direction. The main conceptions on the origin of glaciotectonic disturbances, which have been applied for the area of Poland, do not explain sufficiently those features. In view of great diversity of operating factors, a universal model for glaciotectonics can hardly be constructed. However, many of the cases are explainable in terms of the "static-kinematic conception" proposed in this paper. It is based on the process of cylindrical shearing under prevailing static load, with a good part played by high pore pressure, anisotropy of the medium and its dilatant response to the strain.