Geophysical Journal | 2000 volume 22 Ή5

Study of the lithosphere structure in the Western Carpathian-Pannonian basin region based on integrated modelling

© Hermann Zeyen*, Miroslav Bielik**, 2000

Bouger anomaly, topography and surface heat flow data were analysed jointly along a transect in NNW-SSE direction across the European Platform, all geological units of the Western Carpathians and the Pannonian Basin to determine its lithospheric thermal structure. A finite element algorithm that integrates the different physical concepts of gravity, local isostatic topography and conductive heat transport links the data sets through thermal expansion. The new model shows a relatively thin lithosphere underneath the Polish foreland (100-120 km) with indications for a flexural foreland bulge of about 200 m height. The data of the Pannonian Basin cannot be completely explained with a standard uppermost mantle. Possible lithosphere-asthenosphere configurations include a surprisingly thick lithosphere (110-120 km), a lithosphere which has recently been rapidly thinned from underneath or an uppermost mantle being 5-10 kg/m3 denser than usual suboceanic mantle which may be explained by enrichment due to a plume. The thickness of lithosphere on average of 80 km in the Pannonian basin is predicted. The first results of integrated modelling in the Western Carpathian mountains also indicate a thickened lithosphere which is interpreted as small remnants of subducted slab.

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