Architecture and Evolution of the Late Jurassic-Early Cretaceous Carbonate Platform Developed upon the SW Margin of the East-European Craton (SE Poland, W Ukraine)

Jacek Gutowski¹, Ihor V. Popadyuk², Piotr Gliniak³, Piotr Krzywiec¹, Andrzej Maksym⁴, Andrzej Urbaniec⁵, and Zbigniew Zlonkiewicz^6
1Polish Geological Institute, Warsaw, Poland
²Scientific Research Institute of Oil and Gas Industry of National Joint-Stock Company “Naftogaz of Ukraine”, Kyiv, Ukraine
³Polish Oil and Gas Company, Warsaw, Poland
⁴Polish Oil and Gas Company, Jaslo, Poland
⁵Polish Oil & Gas Company, Krakow, Poland
⁶Polish Geological Institute, Kielce, Poland

Well, outcrop and seismic data are used to restore on a series of paleo-maps architecture and evolution of the carbonate platform developed during Oxfordian through Valanginian times upon the northern shelf of Tethys (SE Poland and W Ukraine). The platform developed in a transition zone between the epicontinental Mid-Polish Trough and the outer-Carpathian basins. Recently, location of the Tethyan shelf margin has been recognized beneath the Carpathian nappes using gravity images. A variety of depositional systems included open shelf sponge-microbial bioherms, coral reefs and oolitic-bioclastic grainstones which formed hydrocarbon reservoirs in connection with overlying Cenomanian sandstones. Paleogeographic distribution of the depositional systems evolved in time and was controlled by syn-depositional basement normal/transtensional faulting. A series of analogue models helped to understand a role of strike-slip movements along deep faults (bounding basement microplates) related to modifications of extension direction. These movements controlled faults geometry and depocenter shifting. Pelagic black bituminous shales deposited in front of the bioherm-reef belt on the shelf margin are fairly promising source rocks. Quality of the reservoir was enhanced by diagenesis (e.g. dolomitization), fracturing and pre-Cenomanian carstification. The reservoirs are sealed by Miocene evaporates and Upper Cretaceous marls.
In Late Cretaceous main basement fault zones were inverted during the Carpathian collision. The Mid-Polish Trough, located in front of the orogenic belt, was inverted in latest Maastrichtian and Palaeogene. As a result of the Carpathian thrusting, the basin was in the southernmost part covered by the Miocene sediments of the Carpathian foredeep and/or by the Carpathian nappes.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece