HORVATH, FRANK, Eotvos University, Budapest, Hungary, GEORGE POGACSAS, Geophysical Exploration Co., Budapest, Hungary, SIERD CLOETINGH and PAUL REEMST, Free University, Amsterdam, Netherlands, and ATTILA SZABO, Geophysical Exploration Co., Budapest, Hungary

ABSTRACT: An Improved Model for the Evolution of the Pannonian Basin and some of its Consequences for Hydrocarbon Exploration

New data from industrial and academic reflection seismic profiling allow construction of long geological sections across the Pannonian basin depicting the geometry of the sedimentary troughs and the underlying crust. In addition, recent results of sequence stratigraphic analyses, combined with a couple of magnetostratigraphically dated borehole sections, have led to a precise knowledge of the regional chronostratigraphic conditions and facies changes in the basin fill.

The inferred subsidence history reveals interesting anomalies, particularly during the late stage period. The central part (Great Hungarian Plain) has undergone accelerated subsidence, while its western flank (Transdanubia and Styrian basin) as well as the eastern flank (Apuseni Mountains and Transylvanian basin) experienced uplift. Modeling of the subsidence history using two-dimensional algorithms and realistic rheological profiles for the lithosphere explains these observations in terms of a remarkable increase of intraplate stress, as recent as 4 to 2 Ma.

Our new model can have an important bearing on hydrocarbon exploration in the Pannonian basin because it provides a better temperature history and allows more accurate prediction of maturity conditions, calls attention to the significance of late-stage fault reactivation and folding in producing traps, and suggests that stress increase and uplift of geopressured basin and/or basement rocks could have induced massive fracturing and, thus, created high secondary permeability conditions and a revival of fluid-flow systems.

AAPG Search and Discovery Article #90990©1993 AAPG International Conference and Exhibition, The Hague, Netherlands, October 17-20, 1993.