PRZYSTROPOWA SERIA KLASTYCZNA PSTREGO PIASKOWCA DOLNEGO I ŚRODKOWEGO JAKO ZAPIS TRANSGRESJI MORSKIEJ Z ZACHOWANIEM CIĄGŁOŚCI SEDYMENTACJI WE WCZESNYM TRIASIE SYNKLINY GRODZIECKIEJ, SUDETY

Abstract

THE UPPERMOST CLASTIC SUCCESSION OF THE LOWER-MIDDLE BUNTSANDSTEIN AS A RECORD OF CONTINOUS SEDIMENTATION DURING EARLY TRIASSIC TRANSGRESSION IN THE GRODZIEC SYNCLINE AREA, SUDETES

Abstract. The uppermost clastic succession of Lower–Middle Buntsandstein sediments of the Grodziec Syncline (North Sudetic Synclinorium) shows high macroscopic similarity to overlying Cenomanian deposits. That might have resulted in erroneous determination of the boundary between Triassic and Cretaceous sediments in historic drill holes. Detailed macroscopic observations were performed on cores and samples taken for microscopic analyses. A number of features characterizing sediments of the uppermost clastic succession have been identified. These are predominantly increased kaolinite content, decrease of textural maturity, decline of bedding, and lack of pebbles and argillaceous intraclasts. These features might indicate transgressive character of the sediments and deposition in a transitional, terrestrial to marine environment.