Czerwony spągowiec w strefie Bielica-Olszanowo w świetle nowych badań
Abstract
ROTLIEGENDES OR THE BIELICA - OLSZANOWO ZONE (NW POLAND) IN THE LIGHT OF NEW STUDY
Summary
The Rotliegendes of the Bielica-Olszanowo region is represented by the Saxonian sedimentary series which overlies the Upper Devonian deposits. The two fold division in the Saxonian includes the grey-coloured sandy-clayey series up to 8.0 m thick and the brown-coloured sandy-muddy-clayey series from 30 to 50 m thick. At the base of the grey series, conglomeratic bed or bed with clay balls, 5 to 7 cm thick, occur. Below the erosional boundary a decoloured (grey-brown) series, which is genetically related to the brown series, was recorded. In the composition of the grey series, quartz is dominating (65 -90%), and the content of alkaline feldspars and plagioclases is up to 7%. The cement (up to 15%) is usually carbonate-clayey. In the composition of the brown series, quartz is dominating as well (50- 70%), and the content of alkaline feldspars and plagioclases is up to 4%. Grains of carbonate grains (up to 10%) are relatively abundant, and the cement (up to 35%) is carbonate and carbonate-clayey. Sandstones of the both-series belong to the arcosic-lithic arenites. The features of the grey series deposits indicate the origin in aqueous environment, and the brown series deposits originated in river and continental environments. The problem of the Rotliegendes-Zechstein boundary remains open. The grey series contains no faunal or palynologic documentation; the occurrence of distinctive erosional boundary allows to put that boundary at the bottom of grey series. The Rotliegendes deposits are the most important target for exploration of gas deposits in the Polish Lowland; it seems that the grey series where in the Czarne 1 borehole, gas was recorded, is promising target as well.
Summary
The Rotliegendes of the Bielica-Olszanowo region is represented by the Saxonian sedimentary series which overlies the Upper Devonian deposits. The two fold division in the Saxonian includes the grey-coloured sandy-clayey series up to 8.0 m thick and the brown-coloured sandy-muddy-clayey series from 30 to 50 m thick. At the base of the grey series, conglomeratic bed or bed with clay balls, 5 to 7 cm thick, occur. Below the erosional boundary a decoloured (grey-brown) series, which is genetically related to the brown series, was recorded. In the composition of the grey series, quartz is dominating (65 -90%), and the content of alkaline feldspars and plagioclases is up to 7%. The cement (up to 15%) is usually carbonate-clayey. In the composition of the brown series, quartz is dominating as well (50- 70%), and the content of alkaline feldspars and plagioclases is up to 4%. Grains of carbonate grains (up to 10%) are relatively abundant, and the cement (up to 35%) is carbonate and carbonate-clayey. Sandstones of the both-series belong to the arcosic-lithic arenites. The features of the grey series deposits indicate the origin in aqueous environment, and the brown series deposits originated in river and continental environments. The problem of the Rotliegendes-Zechstein boundary remains open. The grey series contains no faunal or palynologic documentation; the occurrence of distinctive erosional boundary allows to put that boundary at the bottom of grey series. The Rotliegendes deposits are the most important target for exploration of gas deposits in the Polish Lowland; it seems that the grey series where in the Czarne 1 borehole, gas was recorded, is promising target as well.