Amber and organic matter from the late Oligocene deep-water deposits of the Central Western Carpathians (Orava-Podhale Basin)

The occurrence of amber in the Central Carpathian Paleogene Basin is reported here for the first time. The amber has been analyzed by means of optical microscopic methods, infrared spectroscopy, gas chromatography/mass spectrometry, and pyrolysis-gas chromatography/mass spectrometry to understand the amber composition, origin, taphonomy, alteration, and diagenesis. Organic petrographic and reflectance analyses of organic matter from amber-bearing sediment was carried out to get information about paleoenvironment and maturity of sedimentary rock. Analyses confirmed polylabdane structure associated with Class Ib-type of amber and its possible origin from the conifer family Araucariaceae. It is characterized by a high degree of maturity, where both temperature and exogenic processes have participated in its conversion. Heterogeneity of reflectance values in the resinite suggests that amber was not redeposited from an older and more mature sedimentary unit. The discrepancy between the maturity of the amber and amber-bearing sedimentary rock, along with abundant char and inertinite macerals indicates a probability of thermal alteration of the amber under the influence of heat from a wildfire and increased maturity occurring before its ultimate burial in a deep-sea environment. The assemblage of terrigenous macerals and numerous char and inertinite particles which were found in amber-bearing sediment, as well as in the amber crust, suggest forest-swamp type vegetation affected by wildfires. The presence of amber and predominantly terrigenous organic matter, besides mud rip-up clasts derived from freshwater sediments in deep-marine deposits, indicates a direct connection of terrestrial environments to the deep-water depositional system.