Abstract: The nature of the Mid-Hungarian line

CSONTOS, LASZLO and ANDRAS NAGYMAROSY

The Mid-Hungarian line is a major tectonic element of the Intra-Carpathian basin. It separates two blocks of different origin: Alcapa to the north and Tisza-Dacia to the south. The line itself is hidden beneath thick Tertiary deposits and volcanites on almost its entire length.

Seismic sections across the deformation zone show several flat north-dipping normal faults and transtensional flower structures. Reconstruction of the observed offsets puts Alcapa basement above the Tisza basement. Thrusting is interpreted to be Late Paleogene-Early Miocene.

In some regions adjacent to the Mid-Hungarian line a more complex tectonic history was deduced. This is characterized by Late Paleogene-Early Miocene thrusting and folding along an ENE-WSW directed right lateral fault zone; a Middle-Late Miocene normal faulting and extension, presumably along the same main faults; a Late Miocene inversion; a Late Miocene-Pliocene transtension along ENE-WSW directed corridors; and locally Pliocene?-Quaternary inversion.

Large amplitude thrusting coupled with right lateral motion opens new hydrocarbon perspectives along the Mid-Hungarian line. These range from possible overlap and thrusting of Paleogene source rocks to formation of potential source rocks in the deep extensional grabens. A complicated late tectonic history can enhance trapping, but can also result in bleaching of the reservoirs.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria