Gravitationally-geological model of the Polar Urals transect

Abstract

Research subject. The Polar Urals seismic transect area. Aim. To develop and consider a new gravitational computer model of the Polar Urals seismic transect, containing 29 layers and 225,388 cells. Methods. Geological, gravity and magnetic, and seismic data on the Polar Urals seismic transect (A.V. Rybalka et al.); the authors’ modeling method. Results. A new geological and geophysical model was developed. This model refines the existing ideas on the geological structure of the Polar Urals and the basement (Pre-Jurassic basement) of the Western part of the West-Siberian plate along the Polar Urals seismic transect to the depth of 15 km. Our studies have confirmed the high quality of works on the Polar Urals seismic transect headed by A.V. Rybalka. The developed model gives a more detailed representation of the structure of the Earth crust along the transect. The geological map of the basement of the Pre-Urals part of the West-Siberian plate was refined. Thus, according the geomagnetic map, we included numerous arrays of serpentinite; in granite-gneiss, we allocated different density areas (2.67 + 0.06, 2.67 + 0.02, 2.67 + 0.09 g/cm3); in the North part of the map, the model consist of four  group of the rock of different density 2.67 + 0.12, 2.67 + 0.05, 2.67 + 0.06 and 2.67 + 0.08 g/cm3; this formation to the Source-East of the transect is modeled by rocks with density 2.67 + 0.19, 2.67 + 0.06, 2.67 + 0.14, 2.67 + 0.06, 2.67 + 0.04 g/cm3. We also introduced granite of the gabbro-granite formation mainly northward of the city of Salekhard. Cenotypal effusive Triassic rocks (mainly basalt) join to them from North-West and Source-East. In the Source-East corner of the map we introduced gabbro and unweathered ultrabasite. Conclusion. A 3D density model in the vicinity of the Polar Urals seismic transect using an anomalous magnetic map was developed. The geological map of the region was clarified.