P-WAVE VELOCITIES IN THE UPPER MANTLE OF PLATFORMS

 2021 V.V. Gordienko*, L.Ya. Gordienko

Institute of Geophysics named after S.I. Subbotin, National Academy of Sciences of Ukraine, Kiev, Ukraine

* e-mail: gordienkovadim39@gmail.com

Abstract. The study of the velocity section of the upper mantle of the continental platform is the final one in the series of works by the authors devoted to the analysis of similar one-dimensional models for regions with all types of endogenous regimes on the continents and oceans. They reveal features common to them that distinguish them from regions with a different geological history inherent in the upper mantle. The assumption about such features is based on previously constructed schemes of deep processes and thermal models corresponding to the advection-polymorphic hypothesis (APH). It can be assumed that it is difficult to solve the problem for this particular endogenous regime. Zones of modern activation with a fundamentally different type of velocity section of the upper mantle are widespread on the platforms. The study of previously constructed velocity sections of the platforms on all continents made it possible to find areas with a preserved inactive regime. The only exception was the territory of South America. The authors' own constructions made it possible to identify the platform section only for Ukraine and only in a limited range of depths. In other cases, the constructed travel time curves clearly reflected the results of the passage of seismic waves through the mantle of the platforms proper and zones of modern activation. Special studies of the Ukrainian mantle showed that the latter occupy about half of the platform's territory. The situation on the platforms of other continents turned out to be close, and the travel time curves were almost identical. The selected velocity section (corresponding to the average experimental travel time curve) turned out to be close to the average between the calculated ones (according to the APG) for the platform and the zone of modern activation.

Keywords: continental platforms, zones of modern activation, velocity sections of the upper mantle.

About the authors

GORDIENKO Vadim Vyacheslavovich – Institute of Geophysics named after S.I. Subbotin, National Academy of Sciences of Ukraine. Ukraine, 03680, Kiev, Palladin av., 32. E-mail: gordienkovadim39@gmail.com

GORDIENKO Lyudmila Yakovlevna – Institute of Geophysics named after S.I. Subbotin, National Academy of Sciences of Ukraine. Ukraine, 03680, Kiev, Palladin av., 32. E-mail: lyagord@gmail.com

Cite this article as: Gordienko V.V., Gordienko L.Ya. P-wave velocities in the upper mantle of platforms, Geofizicheskie Protsessy i Biosfera (Geophysical Processes and Biosphere), 2021, vol. 20, no. 1, pp. 14–22 (in Russian). https://doi.org/10.21455/GPB2021.1-2

English version: Izvestiya, Atmospheric and Oceanic Physics, 2021, vol. 57, iss. 7. ISSN: 0001-4338 (Print), 1555-628X (Online). https://link.springer.com/journal/volumesAndIssues/11485