Biostratygrafia danu i paleocenu z Nasiłowa i Bochotnicy w świetle analizy ichtiofauny

Abstract

BIOSTRATIGRAPHY OF DANIAN AND PALAEOCENE FROM NASIŁÓW AND BOCHOTNICA IN THE LIGHT OF ICHTHYOFAUNA Summary The paper deals with the results of study on ichthyofauna from the boundary beds between the Cretaceous and Tertiary, and from the Palaeocene, found to occur at Nasiłów and Bochotnica, near Kazimierz Dolny on Vistula River (Central Poland). A list of forms is given together with their vertical range (Tab. I). Based on the analysis of the ichthyofauna the author was able to distinguish here the following horizons: Upper Cretaceous (Maastrichtian), Danian 8.S., Dano-Montian, Thanetian, and the lowermost Sparnacian (Fig. 2). It is demonstrated that the Danian deposits, determined on the basis of foraminifer microfauna, comprise - according to the ichthyofauna - Danian s. s., Dano-Montian and partly Thanetian, whereas the Montian deposits Thanetian and probably Lower Sparnacian (Fig. 2). The ichthyofauna of the individual horizons is typical and corresponds to that of the Danian, Montian, Thanetian and Sparnacian (Lower Londenian) of West and North Europe stratotypes. It has been ascertained that the ichthyofauna here considered forces to refer the Danian to the Upper Cretaceous. A short ecological analysis has been made of the fish associations in the individual horizons, and new conclusions have been drawn on this basis, concerning both bathymetric changes in the sedimentary basis, and climate evolution at the Cretaceous-Tertiary and the Palaeocene times in the area studied. It has ' also been demonstrated that these facts lead to a new palaeogeographical reconstruction of the then extents of the continent and of the sea in the area of Central and North Poland. Palaeogeographical value of the ichthyofanua, the most typical and complete in Central Europe, has been discussed, •and possibilities have been presented of a new correlation of the Palaeocene in Central Poland with the epicontinental Palaeocene of the Ukraine and the Dnieper - Donets foredeep.