The depth geodynamic state and its correlation with the surface geological and geophysical parameters along the sublatitudinal profile of Eurasia

A cross‐sections of longitudinal (P) and transverse (S) wave anomalies (attribute δ(VP/VS)) is constructed along the sublatitudinal profile from the Atlantic Ocean to the Pacific Ocean across the regions of the latest Eurasian volcanism. It is correlated with surface geophysical parameters interpretable in terms of geodynamics: heat flow, seismicity and integrated conductivity of the lithosphere. All the volcanic groups are related to the negative anomalies of S‐ and P‐wave velocity variations at depths, which are observed in the eastern part of the profile from Central Asia to the Pacific Ocean to depths of 1000 km. Such anomalies correlate with the heat flow anomalies and are thus indica‐ tive of a deep source. The absence of deep roots in the western part of the profile from the Caspian to the Western Mediterranean suggests lateral extension of the anomalously ‘hot’ mantle from the Afar branch of the African super‐ plume. The groups of volcanic formations in the Baikal region and the Far East are spatially associated with heat flow anomalies that are three times higher than the background values. A correlation between intraplate volcanism and the lithosphere conductivity suggests the presence of positive anomalies in all volcanic clusters, despite the fact that their background values are considerably different. In the continental part, velocity anomalies are typical of all volcanic groups with positive conductivity anomalies. It is evidenced by seismic tomography that all the volcanic groups (ex‐ cept the Alpine‐Caucasian) have ‘hot’ roots in the upper mantle to depths of 1200 km. The highest maximum conduc‐ tivity values are typical of the zones wherein high intraplate seismicity is absent. Along the profile, there are several zones of high intraplate seismicity, which are separated by aseismic zones or plate boundaries. This suggest the influ‐ ence of the heated state of the mantle and the occurrence of zones of increased conductivity in the lithosphere.

geodynamics, heat flow, seismic tomography, VP/VS ratio, seismicity, conductivity, volcanogenic area

1. Alekseev D., Kuvshinov A., Palshin N., 2015. Compilation of 3D global conductivity model of the Earth for space weather applications. Earth, Planets and Space 67 (1), 108. https://doi.org/10.1186/s40623-015-0272-5.

2. Anderson D.L., Tanimoto T., Zhang Y.S., 1992. Plate tectonics and hotspots: the third dimension. Science 256 (5064), 1645–1651. https://doi.org/10.1126/science.256.5064.1645.

3. ANSS Earthquake Composite Catalog, 2014. Available from: http://quake.geo.berkeley.edu/anss/ (last accessed: February 11, 2014).

4. Becker T.W., Boschi L., 2002. A comparison of tomographic and geodynamic mantle models. Geochemistry, Geophysics, Geosystems 3 (1), 2001GC000168. https://doi.org/10.1029/2001GC000168.

5. Chiarabba C., De Gori P., Speranza F., 2008. The southern Tyrrhenian subduction zone: deep geometry, magmatism and Plio-Pleistocene evolution. Earth and Planetary Science Letters 268 (3–4), 408–423. https://doi.org/10.1016/j.epsl.2008.01.036.

6. Dmitriev L.V., Sokolov S.Yu., Melson V.G., O'Hearn T., 1999. Plume and spreading association of basalts and their reflection in the petrological and geophysical parameters of the northern Mid-Atlantic Ridge. Russian Journal of Earth Sciences 1 (6), 457–476 (in Russian).

7. Everett M.E., Constable S., Constable C.G., 2003. Effects of near-surface conductance on global satellite induction responses. Geophysical Journal International 153 (1), 277–286. https://doi.org/10.1046/j.1365-246X.2003.01906.x.

8. Global Heat Flow Database, 2018. University of North Dakota. Available from: https://engineering.und.edu/research/global-heat-flow-database/data.html.

9. Grand S.P., van der Hilst R.D., Widiyantoro S., 1997. Global seismic tomography: A snapshot of convection in the Earth. GSA Today 7 (4), 1–7.

10. Kuchai O.A., Kozina M.E., 2015. Regional features of seismotectonic deformations in East Asia based on earthquake focal mechanisms and their use for geodynamic zoning. Russian Geology and Geophysics 56 (10), 1491–1499. https://doi.org/10.1016/j.rgg.2015.09.011.

11. Letnikov F.A., 2006. Superdeep fluid systems of the Earth. RFBR Electronic Library (in Russian). Available from: https://www.rffi.ru/rffi/ru/popular_science_articles/o_16705.

12. Melnikova V.I., Radziminovich N.A., 1998. Mechanisms of action of earthquake foci in the Baikal region over the period 1991–1996. Geologiya i Geofizika (Russian Geology and Geophysics) 39 (11), 1598–1607.

13. Moroz Yu.F., Moroz T.A., 2012. Deep geoelectric section of the Baikal rift. Bulletin of Kamchatka Regional Association Educational-Scientific Center. Earth Sciences (2), 114–126 (in Russian).

14. Nurmukhamedov A.G., Nedyadko V.V., Rakitov V.A., Lipatyev M.S., 2016. The lithosphere boundaries in Kamchatka based on data on the earthquake converted-wave method (ECWM). Bulletin of Kamchatka Regional Association Educational-Scientific Center. Earth Sciences (1), 35–52 (in Russian).

15. Podgornykh L.V., Khutorskoy M.D., 1997. Planetary Heat Flow Map. Scale 1:30000000. Explanatory Note. Orgservis LTD Publishing House, Moscow – St. Petersburg, 55 p. (in Russian).

16. Pollack H.N., Hurter S.J., Johnson J.R., 1993. Heat flow from the Earth's interior: analysis of the global data set. Reviews of Geophysics 31 (3), 267–280. https://doi.org/10.1029/93RG01249.

17. Schaeffer A.J., Lebedev S., 2013. Global shear speed structure of the upper mantle and transition zone. Geophysical Journal International 194 (1), 417–449. https://doi.org/10.1093/gji/ggt095.

18. Sokolov S.Yu., 2014. Condition of geodynamic mobility in mantle based on data from seismic tomography and Р and S waves velocity ratio. Bulletin of Kamchatka Regional Association Educational-Scientific Center. Earth Sciences (2), 55–67 (in Russian).

19. Sokolov S.Yu., Trifonov V.G., 2012. Role of the asthenosphere in transfer and deformation of the lithosphere: The Ethiopian-Afar superplume and the Alpine-Himalayan Belt. Geotectonics 46 (3), 171–184. https://doi.org/10.1134/S0016852112030053.

20. Trifonov V.G., Sokolov S.Y., 2017. Sublithospheric flows in the mantle. Geotectonics 51 (6), 535–548. https://doi.org/ 10.1134/S0016852117060085.

21. Trifonov V.G., Sokolov S.Yu., 2018. Structure of the mantle and tectonic zoning of the central Alpine-Himalayan belt. Geodynamics & Tectonophysics 9 (4), 1127–1145 (in Russian). https://doi.org/10.5800/GT-2018-9-4-0386.

22. Van der Hilst R.D., Widiyantoro S., Engdahl E.R., 1997. Evidence for deep mantle circulation from global tomography. Nature 386 (6625), 578–584. https://doi.org/10.1038/386578a0.

23. Zhdanov M.S., Berdichevsky M.N., Shneer V.S., Svetov B.S., Varentsov I.M., Zhdanova O.N., Golubev N.G. Geoelectric model of the transition zone from the Asian continent to the Pacific Ocean. In: Yu.P. Neprochnov, L.R. Merklin (Eds.), Geophysical fields of the Pacific and Indian oceans. International Geophysical Committee, USSR Acad. Sci., Moscow, p. 45–52 (in Russian).