Возможный механизм формирования макрорельефа Верхояно-Колымской орогенной области (на основе анализа геофизических полей)

Abstract

The Verkhoyansk-Kolyma orogenic region is the main element of the morphostructure of the Western part of the Verkhoyano-Chukotka mountain country. The territory of the orogenic region covers the Verkhoyansk system of mountain ranges in the West, the system of Chersky and Momsky ridges in the North-East and Suntar-Khayata ridge in the South. The results of spectral-statistical analysis of the Verkhoyansk-Kolyma orogenic region relief digital models in the various radiuses averaging and separation of the gravitational field at different frequency components, corresponding to different depth levels of the lithosphere, is made to identify the spatial changes in geomorphological and geophysical parameters of the orogenic region, and also conditions of its mountain facilities formation. It is shown that the mountain systems correspond to linear gravitational minima, and the Verkhoyano-Kolyma positive regional anomaly of the low-frequency component of the relief-Verkhoyansk regional gravitational minimum with an amplitude of up to 100 mGal and a diameter of 1100–1200 km. The morphostructure of the Verkhoyansk-Kolyma orogenic region is characterized by a straight relief, which allows the deep structure of mountain structures and their formation to be considered within the framework of their corresponding folded structures. On the example of the Verkhoyansky meganticlinory deep structure, the model of the Verkhoyansky ridge formation is substantiated. Orogenesis of the Verkhoyansk-Kolyma orogenic region is considered on the basis of the proposed model of the deep structure, namely as a result of granitization of the crystalline basement and lower sedimentary layer under the influence of mantle fluids actinolite at depths of 45–120 km. Rheomorphic processes of the crystalline basement resulted in the formation granite-gneiss domes and the rise of mountain ranges.