2011_4

Miocene tectono-sedimentary development in the Moravian part of the Vienna Basin: case study based on subsidence analysis and accomodation rates
Authors: Sopkova B., Prochac R.,
Workshop: Eurocores – Topo – Europe Source & Sink Workshop (Smolenice, Slovakia)
Date: April 9-12, 2011
Language: English
Info: Article PDF (2.32Mb)
Link: Currently not available

Abstract:
Based on subsidence analysis, calculation of accommodation rates, study of well logs and use of 3D seismic attributes sedimentary and tectonic evolution of the Moravian part of the Vienna basin was investigated.

For subsidence analysis several tens of wells were selected, in order to cover the entire area of the Moravian part of the Vienna basin. From individual burial history diagrams periods with increased subsidence were identified and schematic profiles were constructed, which display tectono-sedimentary development of the basin.

According to burial history reconstruction the main phase of tectonic subsidence was recorded during the Middle Badenian, which corresponds to the opening of the Moravian Central Depression (MCD) along the Steinberg and Lanzhot-Hrusky fault systems. The second phase of slightly increased subsidence was observed during the Sarmatian stage. The lasts phase can be regarded as of Late Miocene age (Pannonian).

Calculation of accomodation rates (after decompaction) has shown the highest amounts of sediments during the Karpatian and Middle Badenian stages. Based on the maximal accommodation rates in Miocene depocenters 3 individual stages can be identified. First stage is presented by Eggenburgian, Otnangian sediments. Second stage is represented by Karpatian and Early Badenian sediments. Depocenters of first and second stage were situated on the Hodonin-Gbely block. Third stage includes sediments deposited from the Middle Badenian up to Pannonia with depocenter located in the MCD.

In the Miocene sedimentary record nice examples of lateral and vertical changes in depositional environments can be observed (channesl, crevasse splays etc.), in particular in the Upper Badenian and Sarmatina sediments. These changes are recorded in well logs and in seismic image as well. 3D seismic attributes have revealed several channel systems crossing our study area generally in W-E direction. These channels run from Mistelbach block, across MCD and continue onto the Hodonin-Gbely block without any sign of shift on the faults. They can be predominantly found in the Upper Badenian and Sarmatian deposits. In other words from the beginning of the Late Badenian there is no evidence of strike-slip regime in the Moravian part of the Vienna basin.

The fact, that the channels cross continuously from down-thrown onto the up-thrown fault block can lead to assumption that during the existence of channels accomodation space in the Moravian part of the Vienna basin might have been filled up and tectonic activity might have been ceased, at least on the Lanzhot-Hrusky and Steinberk fault systems. Present geological structure of Vienna basin indicates that the tectonic regime on above mentioned fault systems was apparently restored during the Late Miocene.

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