Forecasting of geological hazards based on the reconstruction of tectonic stress fields within the Krivoy Rog ore region

Abstract

Tectonic-physical studies were carried out within large territory of Kryvyi Rih region, covering all age rocks complexes and areas with different types of structures. Reconstructions of tectonic stress fields of the local level were carried out within the study areas. The initial data were the results of a field study of sliding mirrors, cracks, cleavage planes, layering, microstructural orientations of minerals, which were combined into separate groups according to age and structural features. The reconstructed stress field characterizes the next stage of the structure formation of the Kryvyi Rih ore region, which is compression. The characteristics of this stress field correlate well with the axes of fold deformation of the Cypriot series transverse compression, which means that it is folded. The latest stress field is reliably reconstructed according to the youngest cleavage cracks and discontinuities that cut all the age complexes of the Kryvyi Rih ore region. It is characterized by the strongest variability of the orientations of the local stress axes distribution. On the summary stereograms, 45-degree conical regions corresponding to the minima of the distribution of the axes 1 and 3 are confidently determined, which make it possible to determine the stress axes direction of the regional level.