1. Deep Structure and Geodynamics of the Black Sea–Caspian Region.
- Author
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Pavlenkova, N. I., Yegorova, T. P., Baranova, E. P., and Pavlenkova, G. A.
- Subjects
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GEODYNAMICS , *OCEANIC crust , *INCLUSIONS in igneous rocks , *SEISMIC tomography , *CRUST of the earth , *DATA analysis - Abstract
New data on the crust structure of the Black Sea‒Caspian region, including the Scythian and Anatolian plate margins, the Caucasus, Black Sea and Southern Caspian structures are reported. Generalization and analysis of the data of deep seismic studies with an estimate of their reliability were performed and the velocity sections of the crust were constructed. Based on the data of deep drilling data and studies of the crust composition in xenoliths in these sections, three major layers were identified in the crust: granite-gneiss (6.0‒6.4 km/s), granulite-gneiss (6.5‒6.7 km/s), and basic (6.8‒7.2 km/s). According to the thickness of these layers, the major types of the crust were distinguished. Three continental types with all three layers, but different in the total thickness of the crust types were distinguished in the area of the Scythian and Anatolian plates. The oceanic type with thin basic crust and two transitional types, subcontinental and suboceanic, with the different total thickness of the crust and the thickness of the basic layer were distinguished within the deep sea basins. There are anomalous types of the crust in the Caucasus region: the thick crust of the Lesser Caucasus with anomalously low velocities and the thick high-velocity crust of the Reon‒Kura Trough. According to the seismological data, the crust of the Black Sea–Caspian region is separated from the platform plates bounding it by the deep faults and crossed by two transform faults; the upper mantle of the Caucasus differs from neighboring regions by reduced velocities. Based on the analysis of the material obtained and CDP data on the basement structure, the new structural and geodynamic schemes of the crust of the entire region were compiled, and it was shown that the formation of depressions with oceanic and suboceanic crust types corresponds to the platform regime characteristic of the depressions of Eastern Europe. A new collisional model with the overthrust of the Anatolian Plate crust onto the crust of the Lesser Caucasus without change of the structure of the upper mantle was proposed to explain the structure of the Caucasus region. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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