Inner structure and kinematics of the Sushchany-Perga fault zone of the Ukrainian Shield according to the tectonophysical study

Abstract

The field tectonophysical works were carried out in the upper reaches of the Ubort River basin along the Zolnia-Maidan-Kopischany fault. The research aim was determination of the inner structure and kinematics of the Sushchany-Perga fault zone of the western pfrt of the Ukrainian Shield. For investigation of fracturing and structural-textural elements of rocks the structural-paragenetic method of tectonophysics was used. It was determined that formation of the Sushchany-Perga fault zone continued during at least five phases of deformation. They were accompanied by the formation of differently oriented shear zones: Khmelivka, Sushchany, Perga, Rudnia-Khochin, Lopatychi. The Khmelivka and Sushchany shear zones are similar to striking of the Nemyriv and Khmelnik fault zones of the Ukrainian shield, which belong to the Nemyriv stage of faulting (~1.99 Ga). The Rudnia-Khochin and Perga phases are related to the fact that the Sushchany-Perga fault zone was quite active during the junction of the Fennoscandia and Sarmatia microplates. We have established that the development of thrust fault and normal down throw fault type shears, which took place in an area of compression and extension, respectively, is associated with the formation period of the Perga granitoids complex (1.80—1.70 Ga).This alternation of the compression and extension conditions has led to formation of the ore occurrences and deposits within the Perga tectonic joint. This investigation found that the Sushchany-Perga fault zone arose in the Late Paleoproterozoic at the Nemirov stage of fracture formation, simultaneously with Goryn, Lutsk, Teteriv and Nemyriv fault zones as a result of the junction of two ancient microplates — Fennoscandia and Sarmatia.