Wykorzystanie kalpionelli w biostratygrafii pelagicznych facji węglanowych prowincji tetydzkiej
Abstract
USE OF CALPIONELLIDS IN BIOSTRATIGRAPHY OF PELAGIE CARBONATE FACIES OF THE TETHYAN PROVINCE
Summary
This paper presents applicability of calpionellids to biostratigraphy of the Upper Jurassic - Lower Cretaceous calcareous sequences. This group of microfossils were widespread within the Tethyan Province (Fig. 2). Due to their widespread distribution and rapid evolution, they are good biostratigraphical markers for the Late Tithonian, Berriasian and Early Valanginian. The Standard Calpionellid Zonation, established in 1970 in Rome, contains four zones: the Crassicollaria, the Calpionella, the Calpionellopsis and the Calpionellites zones. This zonation was modified in 1985 in Sümeg (Hungary). The Crassicollaria Zone was subdivided into the Remanei and the Intermedia subzones and the Calpionellopsis Zone into the Simplex and the Oblonga subzones (Fig. 5). The modified Rome Standard Zones have been widely accepted and form the base of regional zonations (e. g. in the Carpathians). The calpionellid scheme is well correlated with the ammonite zonation as well as with other biostratigraphical zonations. The base of the Calpionella Zone is correlated with the Jurassic/Cretaceous boundary, marked by the base of the Jacobi - Grandis Zone (in ammonite scheme). Further studies should attempt at extraction preparation of complete loricae. This could help in solving some taxonomical problems caused by difficulties in determination of oblique sections of calpionellids. Furthermore, correlations between the Standard Calpionellid Zonation and other stratigraphical schemes (e. g. magnetostratigraphical zonation) should be made
Summary
This paper presents applicability of calpionellids to biostratigraphy of the Upper Jurassic - Lower Cretaceous calcareous sequences. This group of microfossils were widespread within the Tethyan Province (Fig. 2). Due to their widespread distribution and rapid evolution, they are good biostratigraphical markers for the Late Tithonian, Berriasian and Early Valanginian. The Standard Calpionellid Zonation, established in 1970 in Rome, contains four zones: the Crassicollaria, the Calpionella, the Calpionellopsis and the Calpionellites zones. This zonation was modified in 1985 in Sümeg (Hungary). The Crassicollaria Zone was subdivided into the Remanei and the Intermedia subzones and the Calpionellopsis Zone into the Simplex and the Oblonga subzones (Fig. 5). The modified Rome Standard Zones have been widely accepted and form the base of regional zonations (e. g. in the Carpathians). The calpionellid scheme is well correlated with the ammonite zonation as well as with other biostratigraphical zonations. The base of the Calpionella Zone is correlated with the Jurassic/Cretaceous boundary, marked by the base of the Jacobi - Grandis Zone (in ammonite scheme). Further studies should attempt at extraction preparation of complete loricae. This could help in solving some taxonomical problems caused by difficulties in determination of oblique sections of calpionellids. Furthermore, correlations between the Standard Calpionellid Zonation and other stratigraphical schemes (e. g. magnetostratigraphical zonation) should be made