The decisive role of the crystalline crust faults in the Black Sea opening.

• Видавець: Subbotin Institute of Geophysics of the NAS of Ukraine
• Дата: 2017
• Автори: Rusakov, О. M., Pashkevich, І. K.
• Формат: Стаття
• Мова: English
• Опубліковано: Subbotin Institute of Geophysics of the NAS of Ukraine 2017
• Теми: Black Sea; crystalline crust; faults; opening mechanism.
• Онлайн доступ: https://journals.uran.ua/geofizicheskiy/article/view/93998

The results of the international "Geology without Limits" project unequivocally confirmed the faults pattern in the crystalline crust of the Black Sea delineated from gravity and magnetic data. The locations of 135 from among ca. 150 faults on its surface derived from the seismic sections of this project completely coincide with those of the present study used. For the first time, we introduced clear evidence for the decisive role of the crystalline crust faults in the opening of the Black Sea. The long-lived Odessa-Sinop (OS) fault zone of the Precambrian origin was of prime importance for this process. It separated the рге-rift continental crust into two blocks with a different geological structure definitely recognized by an integrated geophysical analysis. The West Black Sea and East Black Sea Basins opened by two distinct mechanisms. The western basin, except its eastern part, opened behind a continental fragment that orthogonally rifted and moved towards the southeast along two parallel deep fault zones: the sinistral OS (together with the West Crimean — Pontides) and dextral Balkanides — Pontides (BP) faults. The rest of the Black Sea Basin has originated through the anticlockwise rotating of a large continental block that produced the breaking of the EBSB rift and forming Odessa-Sinop-Ordu (OSO) fault zone. The dextral strike-slip faults in this zone caused the opening of eight local pull-apart basins in the southeastern West Black Sea Basin. The OS fault system, as a long-term feature appears to control the strikes of the Western and Eastern Pontides and the present-day obliquity between the main rift axes of the Black Sea sub-basins. The direct southeastern prolongation of the OS fault forms the western boundary of the pre-Cretaceous strata of the Eastern Pontides.