Abstract: The Carpathians of Southern Poland: Thrust Tectonics or Wedge Tectonics?

JONES, PETER B.

Petroleum Exploration along the northern margin of the Alpine foothills thrust belt of the Entlebuch and Murnau areas of Switzerland and southern Germany has shown that the frontal margin of that section of the Alps is characterized by a system of underthrust wedges delaminating the autochthonous foreland sequence and uplifting the southern edge of the Molasse basin, forming a classic "triangle zone" or "passive-roof duplex" structure clearly illustrated on seismic profiles. Similar structures produced by thrust wedging have also been demonstrated in the outer Carpathians of Romania, originally from well data and more recently from improved reflection seismic profiles.

Lying between those two areas of petroleum exploration is the northern margin of the outer Carpathians in Southern Poland and Ukraine which has traditionally been interpreted as an overthrust margin along which all thrust faults emerged at the surface, without the delamination and thrust wedging that is characteristic not only of the neighboring areas but of Alpine and other foreland thrust belts around the world. The anomalous condition of this region may be more apparent than real Recent well and seismic data in the vicinity of the Carpathian mountain front, south and east of Krakow in southern Poland, demonstrate the presence of several north-verging thrust wedges emplaced along a Miocene evaporite unit, causing delamination and uplift of the overlying section. In several cases purported "autochthonous" Miocene sandstone reservoirs are structural traps within wedges, beneath the Carpathian and Stebnik thrust sheets. Revised relationships between the "autochthonous Miocene", "folded Miocene", and "transgressive Miocene" may suggest new exploration approaches.

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