Cretaceous Oceanic Red Beds in the Outer Western Carpathians, Czech Republic

Abstract

Study of the Upper Cretaceous oceanic red beds (CORBs) in the Outer Western Carpathians, Czech Republic, was based on integrated biostratigraphy (foraminifera, dinoflagellata, calcareous nannofossils). Agglutinated foraminifers are the only abundant microfossil group in red shale. Reconstruction of the sedimentary paleoenvironment was supported by mineralogical and paleoichnological analysis. Bioturbation and lack of organic matter indicate highly oxic sedimentary conditions. The CORBs range from the Albian to the Lower Paleocene. Both their bases and their tops are heterochronous through individual facies zones of the Outer Carpathians. Generally, the time span of the CORBs decreases from abyssal to slope facies and from inner to outer zones. The CORBs reached their maximum extent during the Turonian. The CORBs were terminated by increased influx of terrigenous organic matter.