Aptian foraminiferal stratigraphy and Nannoconus assemblages from the Kopka section (Western Tatra Mountains, Poland)

Andrzej Pszczółkowski

Abstract


In the Kopka section (Dolina Kościeliska valley, Western Tatra Mountains), the upper part of the Kościeliska Marl Formation consists of biomicrites with marly interbeds. These deposits, 76 m thick, are assigned to the Praehedbergella excelsa and Leupoldina cabri zones, of Aptian age. The taxa identified belong mainly to the genera Praehedbergella Gorbachik and Moullade, 1973, Globigerinelloides Cushman and Ten Dam, 1948 (emended by Longoria 1974 and Verga and Premoli Silva, 2003a) and Gorbachikella Banner and Desai, 1988. Nineteen Nannoconus taxa were identified during an SEM study of 34 samples. The occurrence of N. vocontiensis in the higher part of the section allows the nannoconid assemblages in the upper part of the section to be distinguished from those in the lower part. Four Nannoconus assemblages were recognized in these limestones: (1) Nannoconus bucheri-N. steinmannii, (2) N. truitti frequens, (3) N. vocontiensis and (4) N. aff. regularis. The wide-canal Nannoconus specimens are more frequent than the narrow-canal ones in the limestones of earliest Aptian age (Praehedbergella excelsa Zone), but the wide-canal forms predominate consistently in the upper part of the section, still within the L. cabri Zone.


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