EGU21-4070, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-4070
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

The Evolution of the Paleo-Danube Deltas of the Lower Pannonian in the Vienna Basin 

Arthur Borzi1, Werner E. Piller1, Mathias Harzhauser2, Wolfgang Siedl3, and Philipp Strauss3
Arthur Borzi et al.
  • 1Institute of Earth Sciences, NAWI Graz Geocenter, University of Graz, Heinrichstrasse 26, 8010 Graz, Austria; (werner.piller@uni-graz.at)
  • 2Geological – Paleontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria; (mathias.harzhauser@NHM-WIEN.AC.AT)
  • 3OMV Exploration & Production GmbH, Trabrennstraße 6 – 8, 1020 Vienna, Austria; (philipp.strauss@omv.com)

ABSTRACT

The Vienna Basin is a rhombohedral SSW-NNE oriented Neogene extensional basin that formed along sinistral fault systems during Miocene lateral extrusion of the Eastern Alps. The basin fill consists of shallow marine and terrestrial sediments of early to late Miocene age reaching a thickness of 5500 m in the central part of the basin. The early Pannonian was a crucial time in the development of the Vienna Basin, as It coincided with the formation of Lake Pannon. The lake formed at 11.6 Ma when a significant regressive event isolated Lake Pannon from the Paratethys Sea, creating lacustrine depositional environments. At that time the delta of the Paleo-Danube started shedding its sediments into the central Vienna Basin. Based on an existing age model delta deposition commenced around 11.5 Ma and continued until 11.1 Ma. These subsurface deltaic deposits of the Hollabrunn-Mistelbach Formation represent the coeval fluvial deposits of the Paleo-Danube in the eastern plains of the North Alpine Foreland Basin. Therefore, the Palaeo-Danube represents an extraordinary case in where coeval fluvial and deltaic deposits of a Miocene river are continuously captured.

This study provides an interpretation of depositional architecture and depositional environments of this delta in the Austrian part of the central Vienna Basin based on the integration of 3D seismic surveys and well data. The mapped delta has an area of about 580 km2, and solely based on the geometry we classify the delta as a mostly river – dominated delta with significant influence of wave – reworking processes. For seven time slices paleogeographic maps are created, showing the interplay between the lacustrine environments of Lake Pannon, delta evolution and fluvial systems incising in the abandoned deltaplain. Onlaps between single deltalobes indicate a northward-movement of the main distributary channel. Approximate water-depth estimates are carried out with in-seismic measurements of the true vertical depth between the topset deposits of the delta and the base of the bottomset deposits. These data suggest a decrease of lake water depth from about 170 m during the initial phase of delta formation at 11.5 Ma to about 100 m during its terminal phase at 11.1 Ma. A major lake level rise of Lake Pannon around 11.1 Ma caused a flooding of the margins of the Vienna Basin, resulting in a back stepping of riverine deposits and termination of delta deposition in the study area.

 

How to cite: Borzi, A., Piller, W. E., Harzhauser, M., Siedl, W., and Strauss, P.: The Evolution of the Paleo-Danube Deltas of the Lower Pannonian in the Vienna Basin , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4070, https://doi.org/10.5194/egusphere-egu21-4070, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.