SOUTHEASTERN MARGIN OF THE SIBERIAN CRATON – DEEP STRUCTURE AND LATE MESOZOIC GEODYNAMICS

The 3-DV seismic profile data interpretation was used to obtain a geodynamic model for the deep structure of the southeastern margin of the Siberian craton and the South Verkhoyansk sector of the Verkhoyansk fold and thrust belt (VFTB). A determination has been made of the craton boundary, as well as of its reflection in the geological structure and geophysical fields. The model shows the mechanism of formation of thrust complexes on the craton margin and a compensatory underthrust beneath the craton of the lower crustal horizons of the fold-thrust belt, and explains the causes of abnormal RT-conditions reflected in the nature of the manifestation of metamorphism, magmatism, metallogeny and disjunctive tectonics. Using tectonic zoning, the parameters of the model are extended to the structures of the Southern Verkhoyanye and adjacent areas, which made it possible to determine the deep boundaries of the cratonic structures and their borders formed on the oceanic crust. The first are the margins of the Siberian craton and the Okhotsk terrane, the second are the adjacent VFTB structures. The boundary zone between the craton and the VFTB exhibited tectonomagmatic structures with high metallogenic potential. The obtained data make it possible to interpret the tectonic structure and development of the orogenic belt on the craton margin, and to relate the stages of its evolution to large Late Mesozoic geodynamic events in northeast Asia.