Structural evolution of rocks of the Parikvas’shor suite of the Kharbey metamorphic complex (Polar Urals)

The Parikvas'shor suite is a component of the Kharbey gneiss-amphibolite complex and occupies its central part. Most researchers adhere to the idea of the Early Precambrian age of all the strata that make up the Kharbey complex, including the Parikvas'shor suite, but, at the same time, they express different points of view about their relationship in the section. Some researchers believe that the Parikvas'shor suite is the most ancient in the Kharbey complex and composes the Parikvas'shor uplift, while others adhere to an alternative idea of the synclinal occurrence of the Parikvas'shor suite, underlain by gneisses and amphibolites known as the Laptayugan and Khanmeykhoy suites. In recent years, based on new data on isotopic U-Pb dating of zircons, it has also been suggested that the formation of protoliths of crystalline schists of the Parikvas'shor suite, and, possibly, other stratigraphic units of the Kharbey complex, did not occur earlier than the Late Riphean. As the experience of studying other Precambrian metamorphic complexes of the Urals shows, the structural characteristics of rocks and the features of the structural evolution of metamorphic strata can be used as one of the criteria for their relative age. Based on the results of the study of macroand microstructures, it is shown that, starting from the stage of formation of isoclinal folds with steeply dipping hinges, the structures of the Khanmeykhoy and Parikvas'shor suites developed jointly. Folding was accompanied by high-temperature metamorphism of rocks. The folding mechanism was plastic flow in a horizontal compression setting. According to the data on the age of metamorphogenic zircon from the gneisses of the Parikvas'shor suite (1896 Ma) and the structuralgeological relationships of the stratigraphic units that make up the Kharbey complex, all of them, including the Parikvas'shor suite, belong to the pre-Riphean structural stage. Geological relationships, differences in the level of metamorphism of rocks and the nature of folding indicate that the Parikvas'shor suite is the youngest stratum of the Kharbey complex, which composes the Parikvas'- shor syncline.