Model of the structure of the Earth’s crust and Upper Mantle along the Middle Ural transect (Based on the results of Volumetric seismic Density Modeling)

A geological and geophysical model of the structure of the earth’s crust and upper mantle along the Middle Ural transect is presented (as a vertical section of a three-dimensional seismic density model). The methodology for constructing a 3D density model of the earth’s crust and upper mantle for the Middle Urals is outlined. The model was created based on the results of interpretation of gravity anomalies in the Bouguer reduction and deep seismic sounding data. Creating a volumetric one consists of several stages. At the first stage, gradient velocity sections were constructed in the format of grid functions (2D models of seismic velocity distribution) to a depth of 80 km, which were converted into density ones using refined formulas. Next, a threedimensional zero-approximation density model is constructed (using interpolation methods) and the difference between the observed gravitational field and the field of this model is calculated. For the difference field, the inverse problem is solved the density values at the nodes of the computational grid are determined, which need to be added to the zeroapproximation model in order to satisfy the observed field. A comparison is made of the gradient density section obtained by a vertical section of the author’s volumetric density model of the earth’s crust and upper mantle of the Middle Urals along the line of the Middle Ural transect, with a density model created on the basis of a two-dimensional interpretation along this transect (according to the EUROPROBE program). The cross-section of the volumetric density model reflects the main features of the deep structure of the study area, presented in the two-dimensional model, and supplements them with new data on the distribution of physical parameters in the earth’s crust and mantle. This illustrates the fact that a three-dimensional density model, the construction of which takes into account geophysical data specified over the entire study area, carries more information about the structure of the earth’s crust than two-dimensional models.

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