Pages: 515 - 534
Abstract: The Grybów Unit occurring in the Ropa tectonic window was the subject of micropaleontological and geochemi- cal investigation. Studies, based on calcareous nannofossils, proved that the level of reworked microfossil is not higher than 22 % and it varies between two sections. Quantitative analyses of the reworked assemblages confirmed the domi- nation of Cretaceous and Middle Eocene species. The Sub-Grybów Beds, Grybów Marl Formation and Krosno Beds were assigned to the Late Oligocene and represent the terminal flysch facies. Detrital material accumulated in the Oligocene sediments originated from the Marmarosh Massif, which is the eastern prolongation of the Fore-Magura Ridge. The microscopically obtained petrological features agree with the chemical composition of the samples. Mica flakes, rounded grains of glauconite, heavy mineral assemblage, including abraded grains of zircon, rutile and tourma- line as well as charred pieces of plant tissues are reworked components. Enrichment in zircon and rutile is confirmed geochemically by positive correlation between Zr and SiO2. Zr addition is illustrated on 10 ×Al2O3—Zr—200 ×TiO2 and Zr/Sc vs. Th/Sc diagrams. Interpretation of the A—CN—K diagram and variety of CIA and CPA values indicate that the source rocks were intensely weathered granite-type rocks.
Keywords: Grybów Unit, Ropa tectonic window, Oligocene, calcareous nannofossils, mineral composition, geochemistry, recyclingDownload PDF document Show Text Version