ROURE, F., and G. BESSEREAU, Institut Francais du Petrole, Rueil Malmaison, France; and M. KOTARBA, J. KUSMIEREK, and W. STRZETELSKI, Institute of Fossil Fuels, Krakow, Poland

ABSTRACT: Structure and Hydrocarbon Habitats of the Polish Carpathian Province

Geological, geophysical, and geochemical studies have been integrated to explain the structural evolution of the Polish Carpathians, to describe their main hydrocarbon habitats, and to propose a coherent scenario for the history of their petroleum systems.

The western Carpathians form a classic fold-and-thrust belt that is largely overthrust toward the northeast over the Mesozoic platform sequences or even the crystalline basement of the European foreland. Effectively, Neogene synorogenic deposits in the foredeep lie unconformably on early inverted Laramian structures of the autochthon.

In Poland, the allochthonous units of the western Carpathians comprise two distinct assemblages. South of the Pieniny klippen belt, the inner Carpathians are made up of crystalline basement and Mesozoic platform sequences that underwent mid-Cretaceous deformations. In the north, the outer Carpathian flysch units are made up of Cretaceous and Paleogene terrigenous sequences, with interbedded organic-rich Albian blackshale and Oligocene menilite sequences. Pre-Eocene lateral thickness and facies changes in the flysch result from the highly differentiated paleogeography generated by the Laramian episode of inversion. Flexural subsidence developed later, and was followed by Neogene episodes of thrusting.

Besides the occurrence of biogenic gas trapped in the Neogene infill of the Carpathian foredeep, most petroleum exploration is being directed toward the search for oil. Effectively, oil is found either in the Mesozoic carbonates or sandstones of the autochthon (central European platform in the foreland or beneath the allochthon) or in Paleogene sandstone reservoirs of the allochthon.

Recent results of biomarkers analyses suggest a common source rock, e.g., the Oligocene menilite sequence, for the oils found in the allochthon (outer Carpathian flysch units) and a number of oils in the autochthonous European platform (toward the flexural bulge).

These structural and geochemical results allow a new approach to discuss the Carpathian petroleum generation and migration problems.

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