Geodynamic Development Profile - Investigating Miocene geodynamic events in Eastern Alpine basins

Vienna/Leoben (FWF) - The Miocene epoch, part of the early Tertiary period, began some 24 million years ago and saw the development of a wide range of important animals, in particular mammals, and plants. Within the scope of an extensive project cluster sponsored by the Austrian Science Fund, Robert Scholger from the Institute of Geophysics of the University of Leoben is investigating the effects of geodynamic processes on the ecosystems and the environment of the Eastern Alps during the Miocene. The aim of the project is to establish a modern database, which provides comprehensive information about the major Miocene basins and can be made available to anyone interested in the subject.

The European Miocene started out dry, then became extremely humid, then once more dry again and finally ended humid. The climatic situation (glaciation) and the mountain folding processes went hand in hand with changes in the sea level. It is this dynamic epoch in the Earth's history that provided the backdrop for the development of the Eastern Alpine ecosystems. "We want to examine to what extent the geodynamic processes of that time had an impact on these ecosystems with special emphasis on the Vienna, Styrian and Lavanttal basins", Scholger explained, adding, "One of our objectives is to establish a paleomagnetic record of the tectonic movements in Tertiary Eastern Alpine basins".

He will employ various strategies to achieve this goal: In a first approach, sediment basins of the same age located around the Alps will be investigated and compared in order to find out whether these basins have moved relative to each other and to determine in what direction they have basically moved. The second approach involves the use of magnetostratigraphic profiles for a detailed verification of the age of the rock layers. The results of these investigations, together with paleo-ecological and biostratigraphic data will finally allow the geodynamic events that took place in the Eastern Alpine Miocene to be reconstructed.

Comprehensive database
Data acquisition has been largely completed. The data will be evaluated this summer and the database is expected to be available by October. It will meet state-of-the-art technological criteria and will also be made accessible to other people interested in the subject. "One of our first results was that the geodynamic development of the deposits under investigation took place in a counter-clockwise direction. The Vienna and Styrian basins show consistent results indicating a certain geodynamic development - a successive rotation and movement relative to each other", explains Scholger.

The positive impressions and results have motivated Scholger to launch another project in order to investigate specific periods in more detail on the basis of the existing data. The meaningfulness of the new climate indicators, which are based on magnetic parameters, will be examined in direct comparison with traditional methods. New sampling procedures allow research into unconsolidated sediment areas, which have not been accessible to investigation as yet.

Dr. Robert Scholger
Institute of Geophysics, University of Leoben
P +43 (0)3126 50415

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Vienna, 11 April 2002