Informace o publikaci

Synchrony evolution of two contradictory prograding Gilbert-type deltas at the margins of the foreland basin (case study from the Neogene Western Carpathian Foredeep)


BLAŠKO David NEHYBA Slavomír

Rok publikování 2020
Druh Článek v odborném periodiku
Časopis / Zdroj Marine and Petroleum Geology
Fakulta / Pracoviště MU

Přírodovědecká fakulta

Klíčová slova Seismic stratigraphy; sequence stratigraphy; Gilbert-type delta evolution; ruling factors; eustatic sea-level changes vs. fault tectonic activity
Popis The study concerns about two Miocene deltas located along the opposite margins of the Western Carpathian Foredeep (peripheral foreland basin), their architecture and evolution. Three synchrony phases of development of the Gilbert-type deltas were recognized based on 3D and 2D seismic data, well logs and cores. Individual phases are separated by seismic stratigraphy surfaces. The base of the deltas is formed by the erosional discontinuity (seismic stratigraphy surface 1), which is the sequence boundary of the 3rd order cycle. During the first phase, the sediment supply exceeds accommodation space creation and progradation of deltas and the normal regression regime dominates. The first phase is terminated by the maximum regressive surface/transgressive surface (seismic stratigraphy surface 2) and interpreted as the lowstand systems tract. In the second phase, the aggradation and retrogradation regime of deltas reveals the acceleration of the accommodation space creation and the deposits are interpreted as the transgressive systems tract. The third phase is bounded by the maximum flooding surface (seismic stratigraphy surface 3) and shows progradation of the delta in the normal regression regime, then the sediment supply exceeds the accommodation space. The maximum regressive surface (seismic stratigraphy surface 4) terminates this phase and allows to interpret it as the highstand systems tract. The synchrony evolution of deltas is explained by the tectonic activity along the fault system oriented perpendicular to the basin axis. Position of the deltas is also responsible for continuous sediment supply and its variations. The tectonic activity of the transverse fault system across the entire basin hidden the signals of the reciprocal activity of the opposite basin margins directed by flexural tectonics.