An example of the use of structural methods for the correlation and separation of the Upper Riphean and Lower Paleozoic formation of the northern part of the Subpolar Urals

The paper presents the results of studying the macro- and microstructural features of the metamorphic rocks average and top Low Precambrian (Hobein and Moroya suits) and the Lower part Paleozoic (Obeiz suite) sections in the North of the Subpolar Urals. The macro and microstructural features of the rocks of the northern part of the Subpolar Urals, such as the Hobein, Moroya and Obeiz suites are studied in the article. The common structural features for all these formations are both the presence of the falling on the NW at medium and low angles, and the presence of similar orientations of the optical c-axes quartz fabric for rocks which quartz grains experienced translational (dislocation) sliding under compression and shear conditions. The distinctive structural features for the rocks of the Hobein and Moroya formations from the rocks of the Obeiz suite are, firstly, the presence of the early two asymmetric folds with axial planes of of the NE-falling at steep angles, and secondly, the presence of crenulation cleavage observed in the polarization microscope, and thirdly, the existence in these two sets of orientations of optical quartz axes characteristic of rocks that underwent intensive folded deformations. All this allows us to propose additional criteria for the dismemberment and correlation of the metamorphic formations of the Kozhim river basin.