Relationships between tectonics and drainage network planar geometry of the Povcha and Mizoch uplands, NW Ukraine

The Povcha and Mizoch uplands are included in the Volyn Upland and have different geological structure. Unlike the Mizoch Upland, where Miocene limestones form structurally conditioned topography, in the Povcha Upland this strata is preserved only on some small areas. These uplands were selected to evaluate influence of fracture and fault system on development of drainage network in relatively neotectonically stable upland territories. The drainage system was manually derived from 1:10000 scale topographic maps and arranged according to Horton–Strahler ordering using special GIS tools. Some morphometric indices were calculated for estimating of structural control degree on drainage network. Rose diagrams of stream segments direction were created separately for both uplands, and compared with fracture patterns and manually derived valley lineaments. Results suggest that drainage system of the Povcha and Mizoch uplands is characterized by noticeable degree of adjustment to fracture patterns and reflect the dominant trends of neotectonic strain directions. In the Povcha Upland lower structural adjustment degree on drainage network can be explained by partial superimposition and weakness of Cretaceous marlstones that mainly form geological substrate in this area. In general, some quantitative geomorphology methods, statistical analysis of streams and valley lineaments orientation in conjunction with fracture pattern analysis can be successfully applied for studying tectonic and geological influence on drainage network development in upland areas.