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| Titel |
Towards a dynamic model for the formation of the Pannonian basin |
| VerfasserIn |
F. Horvath, O. Sztano, A. Uhrin, L. Fodor, A. Balázs, M. Kóbor, G. Wórum |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250067832
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| Zusammenfassung |
| First applications of a McKenzie-type uniform stretching model to the formation of the
Pannonian basin showed major inconsistencies between predicted vs. observed subsidence
and thermal histories. An alternative model combining moderate crustal extension (stretching
factor of 1.2 to 2.5) and major attenuation of the mantle lithosphere (stretching factor of 5 to
50) resulted in better predictions. It has remained unresolved, however, that this non-uniform
stretching was a simple mechanical response of the rheologically layered lithosphere to
external stress, or a manifestation of interaction between the lithosphere and upper mantle
flows.
The open question of mantle dynamics can be more successfully addressed today, because
of the following conditions:
progress in understanding the infill of the basin during the postrift phase;
better timing of the main Late Miocene through Quaternary stratigraphic
horizons;
availability of seismic data to map basin-scale stratigraphic architecture and
lithological logs from a number of deep wells for reliable decompaction.
A systematic investigation of the western Pannonian basin (Transdanubia) has resulted in new
subsidence history diagrams and maps of the late-stage deformations. It has been found that
the rate of tectonic subsidence during the 11 Ma to 6 Ma time interval was very high (up to
600-800 m/my), which cannot be explained by simple thermal cooling. This period of fast
subsidence was followed by uplift and basin-scale folding with amplitude up to 1000 m from
about 6 Ma to the present. We show that the synforms are usually associated with the former
depocenters and generated largely by compaction of the underlying sediments.
Horizontal movements during the same time interval are dominantly ENE-WSW directed
sinistral strike slips and the related shear features. Although these strike-slip zones
are spectacular features in seismic cross-sections, the slip rates never exceeded 1
mm/y.
Geodynamics of the Pannonian basin has been controlled by rollback of the Carpathian
slab and the stress field generated by the movement of the Adriatic plate. Early postrift rapid
subsidence and the subsequent large scale uplift call for a dynamic influence from the mantle
flow system generated by the rollback of the Carpathian slab. Strike-slip fault activity in the
basin is obviously the consequence of the stress field induced by the rotation and push of the
Adriatic plate. |
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