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2 Studia Geologica Polonica

2 2005

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Comparison of deep-water agglutinated foraminifera from the hemipelagic variegated shales (Lower Turonian-Lower Santonian) and turbiditic Godula beds (Upper Santonian-Campanian) in the Lanckorona-Wadowice area (Silesian Unit, Outer Carpathians, Poland)

Lemańska A.

Studia Geologica Polonica

2005

Vol. 124

259-272

Deep-water agglutinated foraminifera (DWAF) have been studied from variegated shales and Godula beds exposed in the vicinity of Kalwaria Zebrzydowska (Silesian Nappe, Outer Carpa- thians, Poland). Following the standard foraminiferal zonation scheme of Geroch & Nowak (1984), the studied variegated shales can be correlated with the Uvigerinammina jankoi Zone (Lower Turonian-Lower Santonian). The Godula beds can be correlated to the Caudammina gigantea Zone (Upper Santonian-Campanian). Foraminiferal assemblages from the variegated shales are dominated by infaunal and semi-infaunal forms. Their occurrence suggests aerobic bottom water conditions associated with low organic matter availability during the deposition of this unit. Such conditions are presumably related to slow sedimentation rate in low energy, well-oxygenated and oligotrophic bottom environment. In contrast, foraminiferal assemblages from the Godula beds are dominated by epifaunal forms, which collected food from the sediment/water interface. It may suggest that sedimentation took place under relatively higher energy conditions with a higher organic matter flux.

Benthic foraminiferal morphogroups and taphonomy of the Cieszyn beds (Tithonian-Neocomian, Polish Outer Carpathians)

Szydło A.

Studia Geologica Polonica

2005

Vol. 124

199-214

Test gross morphology and taphonomy of calcareous benthic foraminifers from the Cieszyn beds were mainly controlled by depositional parameters, paleoecological conditions and paleogeographical settings. All of these control factors were influenced by a major tectonic event represented by the rifting of the Cieszyn Basin. In its earliest history it acted as a gulf adjacent to the Eastern European Platform. The Tithonian marls and marly shales known in Polish regional geology as the lower Cieszyn shales and Cieszyn limestones yielded highly diverse calcareous benthic foraminiferal assemblages which are dominated by shallow and deep infaunal morphogroups. A remarkably well-developed epifaunal component can be recognized as well. Shelf and peri-reefal foraminifera originally developed their life cycles under well-oxygenated conditions in the immediate proximity of the sea-bottom. The initiation of turbidite sedimentation lead to the removal and transportation of shelf foraminifers into deeper water environments (bathyal). Consequently, the tests of calcareous foraminifers are small, and poorly preserved, presenting dissolution traces, and abraded and corroded surfaces. The mixed and reworked microfauna were replaced by a more uniform one in the proximity of the Jurassic/Cretaceous boundary. Active omnivorous infauna survived not only the change of deposition system but also the deepening of the Cieszyn Basin during Early Cretaceous times. Periodically the supply of reworked and allochthonous calcareous benthic forms into the Cieszyn Basin took place during the Berriasian and Late Valanginian-Hauterivian times.