Some features of the structure of the mantle of the Eastern Mediterranean and their geodynamic interpretation

O. B. Gintov, T. A. Tsvetkova, I. V. Bugaenko, A. V. Murovskaya

Abstract


We consider specific velocity anomalies and the corresponding mantle structures of the East Mediterranean-Black Sea-Caspian region. The anomalies are located on latitudinal and longitudinal seismic tomography sections obtained by constructing 3D P-velocity model of Eurasia applying the Taylor approximation method. The depth of the study is of 50—2900 km. The accuracy of determination of the velocity VP is about ± 0.015 km/s. Velocity sections are shown in residual values ΔVP. Physical and mineralogical mantle model of Pushcharovsky was used for the cross sections specification.

In the 25—30° E cross sections between latitudes of the 34—48°N high-velocity slabs sinking from the northern edge of the African plate and the southern parts of the East-European plate towards each other are seen. Slabs are connected at a depth of about 600 km in the upper mantle transition zone  in the area of 42—43° N. Below the slabs junction  high-velocity mantle zone thickens and extends to a depth of 1000—1200 km that occurs as a result of slabs relatively high-velocity  material accumulation. From this area down-welling begins which can be traced on latitude sections of 35—45° N as an almost continuous inclined layer of ~1100 km width   and ~ 1900 km length. Down-welling submerges from a depth of 450—550 km at Moesian and Aegean micro-plates area to a depth of 1600—1900 km beneath the East Black Sea, Anatolian micro-plates and the northern part of the Arabian plate. The mechanism of the inclined layer formation is discussed with the involvement of global seismic tomography data, and the numerical simulation performed by L. I. Lobkovsky.

In the 42—44° N and 34—36° E sections we trace column type vertical structure, which crosses almost the entire mantle at depths of 50—100 to > 2500 km. In the middle of the column on its axis there is a relatively high-velocity anomaly, which reduces in size and values downward. The shape and structure of the mantle column resembles a "tornado". We consider two possible alternative mechanisms of its formation: a) steep subduction of the West Black Sea micro plate beneath the Central Black Sea Ridge, "wedging" of the mantle and the extension  stresses occurrence  in  border zone I and  middle mantle;  b) rising of the plume from  zone D'',  formation of  extension area in  middle and upper mantle,  lithosphere pulling inward  and  the  subduction zone formation.


Keywords


seismic tomography; high-velocity section; plume; slab; down-welling; mantle; P-waves; micro plates; subduction

References


Bugaenko I. V., Shumlyanskaya L. A., Zaets L. N., Tsvetkova T. A., 2012. Three-dimensional P-velocity model of the upper mantle of the Western Mediterranean. Geofizicheskiy zhurnal 34 (1), 14—31 (in Russian).

Bugaenko I. V., Shumlyanskaya L. A., Zaets L. N., Tsvetkova T. A., 2008. Three-dimensional P-velocity model of the mantle of the Black Sea and the surrounding area. Geofizicheskiy zhurnal 30 (5), 145—160 (in Russian).

Bugaenko I. V., Zaets L. N., Tsvetkova T. A., 2015. Velocity typing the middle and lower mantle of Europe. Geofizicheskiy zhurnal 37(3), 88—101 (in Russian).

Geyko V. S., Bugaenko I. V., Shumlyanskaya L. A., Zaets L. N., Tsvetkova T. A., 2007. 3D P-velocity structure of the upper mantle of the East Mediterranean. Geofizicheskiy zhurnal 29 (4), 13—30 (in Russian).

Gintov O. B., Yegorova T. P., Tsvetkova T. A., Bugaenko I. V., Murovskaya A. V., 2014. Geodynamic features of joint zone of the Eurasian plate and the Alpine-Himalayan belt within the limits of Ukraine and adjacent areas. Geofizicheskiy zhurnal 36 (5), 26—63 (in Russian).

The history of the Tethys Ocean, 1987. Eds A. S. Monin, L. P. Zonenshayn. Moscow: Publ. House of the USSR AS, 155 p. (in Russian).

Lobkovskiy L. I., Nikishin A. M., Khain V. E., 2004. Modern problems Geotectonics and Geodynamics. Moscow: Nauchnyy Mir, 612 p. (in Russian).

Murovskaya A. V., 2012. Fields of stress and deformation modes of the West Crimean Mountains in the Alpine orogeny phase of tectonic data: thesis abstract of the dissertation of the candidate of geological sciences. Kiev, 22 p. (in Russian).

Pushcharovskiy Yu. M., Pushcharovskiy D. Yu., 2010. Geology of the Earth's mantle. Moscow: Geos, 138 p. (in Russian).

Starostenko V. I., Kendzera A. V., Tsvetkova T. A., Bugaenko I. V., 2013. Intermediate earthquakes of the Vrancea zone and velocity structure of the mantle of East Europe. Geofizicheskiy zhurnal 35 (3), 31—45 (in Russian).

Tsvetkova T. A., Bugaenko I. V., 2012. Seismotomography of the mantle under the East European platform: mantle velocity borders. Geofizicheskiy zhurnal 34 (5), 161—172 (in Russian).

Yudin V. V., 2007. Geodynamics of the Black Sea—Caspian region. Kiev: Publ. UkrGGRI, 143 p. (in Russian).

Csontos L., Vörös A., 2004. Mesozoic plate tectonic reconstruction of the Carpathian region. Palaeogeography, Palaeoclimatology, Palaeoecology 210 (1), 1—56.

Forte A. M., Mitrovica J. X., 2001. Deep-mantle high-viscosity flow and thermochemical structure inferred from seismic and geodynamic data. Nature 410, 1049—1056.

Fukao Y., Maruyama S., Obayashi M., Inoue H., 1994. Geologic implication of the whole mantle P-wave tomography. J. Geol. Soc. Japan 100 (1), 4—23.

Graham R., Kaymakci N., Horn B., 2013. Revealing the Mysteries of the Black Sea. GEO ExPro 10 (5), 58—63.

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

Hippolite J. -C., 2002. Geodynamics of Dobrogea (Romania): new constraints on the evolution of the Tornquist—Teisseyre Line, the Black Sea and the Carpathians. Tectonophysics 357, 33—53.

Kaymakci N., Graham R., 2012. The Geodynamics and Evolution of Black Sea Basin revealed by New Deep 2D Seismic regional survey. AAPG Regional Conference: Baku, Azerbaijan.

Kaymakci N., Graham R., Bellingham P., Horn B., 2014. Deep structure and tectonics of Black Sea basin inferred from seismic data (BLACKSEA-SPAN). Special Darius publication of final symposium December 8—9, 2014, 70—71.

Maruyama S., 1994. Plume tectonics. J. Geol. Soc. Japan 100 (1), 24—49.

Stacey F. D., 1995. Theory of thermal and elastic properties of the lower mantle and core. Phys. Earth Planet. Int. 89, 219—245.

Stacey F. D., 1998. Thermoelasticity of a mineral composite and a reconsideration of lower mantle properties. Phys. Earth Planet. Int. 106, 219—236.

Su W., Dziewonski A. M., 1997. Simultaneous inversion for 3D variations in shear and bulk velocity in the mantle. Phys. Earth Planet. Int. 100, 135—156.




DOI: https://doi.org/10.24028/gzh.0203-3100.v38i1.2016.107719

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