--> Abstract: Paleogene Depressions of the Southeastern Slope of the Bohemian Massif, by J. Adamek, F. J. Picha, and J. Sedlak; #90942 (1997).

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Abstract: Paleogene Depressions of the Southeastern Slope of the Bohemian Massif

ADAMEK, JOSEF, FRANK J. PICHA, and JIRI SEDLAK*

The study area, in the southeastern portion of the Czech Republic, covers the contact zone between the Bohemian massif and the West Carpathians. The Bohemian massif is represented there by the igneous rocks of the Brno pluton and its Paleozoic and Mesozoic sedimentary cover. Toward the southeast, the Bohemian massif plunges beneath the Carpathian Neogene foredeep and the nappes of the Carpathian flysch belt with the successor Vienna Basin on top.

Two sub-parallel erosional features, the Nesvacilka and Vranovice depressions are cut into the Mesozoic and Paleozoic carbonate and clastic sequences and, locally, into the crystalline basement rocks. They are filled with up to 1,500 m of Paleogene clastic deposits and buried below the Neogene foredeep and the West Carpathian thrust belt. The Paleogene depressions (paleovalleys) trend in the southeast direction, perpendicular to the strike of the Carpathian belt. The interpretation of gravity and magnetic anomaly fields, combined with seismic and well data, revealed that the development of the Nesvacilka and Vranovice depressions was significantly impacted by the pre-existing structural settings in their basement.

Exploration for hydrocarbons led to discoveries of oil and gas in the central part of the Nesvacilka depression. Jurassic and Paleogene organic-rich marls have been identified as principal source rocks. Generation and migration of hydrocarbons took place after these source rocks were tectonically buried below the Carpathian thrust belt.

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