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Fossils from the Silesian-Subsilesian series of the Polish Western Carpathians : the implications for changes in sea-level and the marine environment during the Albian-Turonian

Szydło A., Jugowiec-Nazarkiewicz M., Olszewska M.

Geological Quarterly

2015

Vol. 59, No. 1

215--228

Fossils and exotics from the Albian-Cenomanian deposits of the Western Polish Carpathians are discussed in relation with changes in depositional environments. Environmental conditions were controlled by geotectonic activity, sea-level changes and also anoxic and biotic events. During the Albian-the Early Cenomanian, and in the Turonian the fall in sea level led to increased supply of coarse-grained material rich in siliceous and sometimes calcareous bioclasts and exotics. This cyclic process has contributed to changes in the marine biota. In the Albian monogenic foraminiferal assemblages with the surficial epifauna corresponding to the organic influx and oxygen deficiency (OAE 1b) were evolved into more variable associations including deep infauna, which indicated more aerobic conditions. Under these conditions also preserved planktonic and calcareous benthic fossils, which indicated the supply of terrigenous material from shallow-water environments and land. During the Albian-Turonian transition intensive subsidence and volcanic activity associated with eustatic sea-level rise led to intensive production of phytoplankton. The sea-surface productivity and enhanced upwelling resulted in expanded short-term oxygen minima at the end of the Albian (OAE 1d) and the Cenomanian (OAE 2). In the latter interval benthic forms almost extinct while siliceous and calcareous plankton survived. In the Turonian changes in sea-level and sedimentary regime led to recolonization of the basin bottom.

Provenance and diagenesis of siliciclastic and organic material in the Albian-Turonian sediments (Silesian Nappe, Lanckorona, Outer Carpathians, Poland): preliminary studies

Wójcik-Tabol P., Ślączka A.

Annales Societatis Geologorum Poloniae

2009

Vol. 79, No 1

53-66

The provenance and diagenesis of the siliciclastic and hemipelagic sediments of three lithostratigraphic units: Lhoty Formation, Barnasiówka Radiolarian Shale Formation (BRSF) and Variegated Shales from Lancko- rona area, Polish Outer Carpathians, was approached by means of petrological and geochemical analysis of the representative samples. Data show that studied succession was mainly derived from two sources: 1. a dominant terrigenous fine-grained components have affinity with average upper continental crust (basing on mineral detritus, K2O/Rb ratio and Y/Ni vs. Cr/V ratios) and 2. biogenic siliceous material and macerals. Composition varies up section and accounts for changes in the detrital supply due to eustatic sea-evel changes. Organic petrology shows presence of organic detritus within the Lhoty Fm and dominance of marine-derived macerals in the BRSF. Chemical and petrological features imply a progressive deepening of the basin. The studied succession was diagenetically altered (e.g. coalification of bituminite, illitisation of smectite and pyritisation).