Dolomit główny w rejonie Bielica - Czarne na tle paleogeografii Pomorza Zachodniego
Abstract
THE ZECHSTEIN MAIN DOLOMITE OF THE BIELICA CZARNE REGION AND ITS PALEOGEOGRAPHICAL POSITION IN THE WESTERN POMERANIA
SUMMARY
Paleogeographical and lithologic-facies relations of the Zechstein (Upper Permian) Main Dolomite of the Bielica - Czarne region are considered in the paper which focuses on influence of geology of the Zechstein substrate on the thickness and facies of the PZ1 (Werra) and Main Dolomite deposits. The latter in the studied region are represented by open marine deposits passing into carbonate platform ones and then into lagoonal deposits. Open marine deposits are represented by laminated micrites of very poor reservoir characteristics. Carbonate platform is formed by oncolites and oolites with subordinate laminated micrites and micrites with relics of bedded stromatolites. A lack of distinct morphological difference during the Main Dolomite deposition resulted in that there is no distinct differentiation between edge of the platform and lagoon zone. Microfacies units have a wide lateral distribution in that area and according to the author, there were unfavourable paleogeographic conditions for the development of morphological form of barrier type in the Bielica - Czarne region. Open marine deposits are limestones, and those from carbonate platform and lagoon are dolomites. This regularity of synsedimentary origin was not influenced by the intensive diagenetic modifications, and is one of basic lithofacies dependents in the northern part of the Main Dolomite basin. Short characteristics of reservoir properties of the Main Dolomite deposits is then presented. Porosity and permeability are lower than in might be supposed considering the lithology. It is concluded that primary porosity and permeability in the Bielica - Czarne region were considerably dimished due to diagenesis. However, the Main Dolomite in this area remains an important target of prospection of hydrocarbons.
SUMMARY
Paleogeographical and lithologic-facies relations of the Zechstein (Upper Permian) Main Dolomite of the Bielica - Czarne region are considered in the paper which focuses on influence of geology of the Zechstein substrate on the thickness and facies of the PZ1 (Werra) and Main Dolomite deposits. The latter in the studied region are represented by open marine deposits passing into carbonate platform ones and then into lagoonal deposits. Open marine deposits are represented by laminated micrites of very poor reservoir characteristics. Carbonate platform is formed by oncolites and oolites with subordinate laminated micrites and micrites with relics of bedded stromatolites. A lack of distinct morphological difference during the Main Dolomite deposition resulted in that there is no distinct differentiation between edge of the platform and lagoon zone. Microfacies units have a wide lateral distribution in that area and according to the author, there were unfavourable paleogeographic conditions for the development of morphological form of barrier type in the Bielica - Czarne region. Open marine deposits are limestones, and those from carbonate platform and lagoon are dolomites. This regularity of synsedimentary origin was not influenced by the intensive diagenetic modifications, and is one of basic lithofacies dependents in the northern part of the Main Dolomite basin. Short characteristics of reservoir properties of the Main Dolomite deposits is then presented. Porosity and permeability are lower than in might be supposed considering the lithology. It is concluded that primary porosity and permeability in the Bielica - Czarne region were considerably dimished due to diagenesis. However, the Main Dolomite in this area remains an important target of prospection of hydrocarbons.