Paleoecology and organie matter in the Late Badenian and Early Sarmatian marine basin of the Polish part of the Carpathian Foredeep

Abstract

The studies aim to determine both the ecological and geochemical conditions of the Late Badenian and Early Sarmatian sedimentary basin located in the outer part of the Carpathian Foredeep. Particularly interesting are: depositional environment of organic matter, depth of the basin and water temperatures. The Late Badenian sea was presumably only slightly deeper than the outer shelf, i.e. about 200 meters. The warm climate resembling that of the warm temperate zone resulted in surface water temperatures 17-20°C. In the Sarmatian the sea depth was initially about 30-50 meters thus, the existenee of submarine meadows was inferred. Then, progressing shallowing to about 10 meters took place. The Sarmatian sea was a warm basin with temperatures roughly corresponding to those of the Late Badenian ones. Organic matter deposited during both the Badenian and the Sarmatian reveals terrestrial origin. Organie matter in the Late Badenian and Early Sarmatian strata is immature or, at most, early matured but at depth below 3000 meters. Very low correlation of both the coneentrations and the maturation degree of the organic matter with its depth of oceurrenee suggest the similarity of sedimentary environments in the whole Miocene succession and the laek of thermal transjormation after deposition. Almost exclusive occurrence of the humic organic matter points to the fast and rhythmic supply of terrestrial clay matter to the deltaic environments in the shallow Miocene basin. A rapid sedimentation of terrestrial, deltaic sediments took place in the Miocene basin, therejore the humic organic matter (type III kerogen) prevailed there and the marine type II kerogen was hardly detectable.