MORPHOLOGY OF EARTH CRUST DENSITY INHOMOGENEITY IN THE ULAANBAATAR REGION (MONGOLIA) BY GRAVITY DATA
According to the results of a medium scale areal gravity survey, performed on the territory of the Ulaanbaatar region (Central Mongolia) a map of gravity anomalies in Bouguer reduction has been obtained. The models of the largest density inhomogeneity in the area - Ulaanbaatar depression and Bogdoulinsky granite massif - are built on the basis of the result interpretation of the medium scale gravity survey of the Ulaanbaatar region. It is found that the depression foundation has a block structure and is complicated by two basins. The thickness of sedimentary deposits in the western basin is about 150 m, while in the eastern basin it can reach 300 m. The thickness of Bogdoulinsky massif granitoids reaches 4.5 km. Information about the shape and size of these inhomogeneities can be used in engineering and seismic works in order to specify the seismic hazard of some parts of the city of Ulaanbaatar.