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The Belemnitella stratigraphy of the Upper Campanian : basal Maastrichtian of the Middle Vistula section, central Poland

Remin Z.

Geological Quarterly

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2015

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Vol. 59, No. 4

783--813

EN

This taxonomy and stratigraphy of the Upper Campanian and Lower Maastrichtian Belemnitella lineages, from the Middle Vistula sections, based on new collections, is presented. The correlation to the basal Maastrichtian standard GSSP at Tercis, France, is provided based on inoceramid bivalve stratigraphy. The Artificial Neural Networks (ANN), particularly the self-organizing Kohonen algorithm, was applied to taxonomic discrimination. Eight morphotypes within the genus Belemnitella, understood here as natural species populations, were recognised. Five of these are assigned to known taxa: Belemnitella mucronata, B. posterior, B. minor [= B. minor I and B. minor II], B. langei and B. najdini; and three, B. sp. a, B. sp. 1 and B. sp. 2, are left in open nomenclature. Four Belemnitella zones are proposed. Due to its palaeogeographic position, between Western and Eastern Europe, the Middle Vistula section is characterized by the co-occurrence of Belemnitella species from those two areas. Consequently, it enables better correlation of Belemnitella-based schemes; the East European B. najdini and B. posterior are placed next to West European B. minor chronospecies I and II. The Campanian/Maastrichtian boundary, as currently defined, is placed at the top of the najdini – posterior Zone, which is an equivalent of the Belemnella-based boundary, i.e. at the base of the Belemnella obtusa / Belemnella vistulensis zones. Within the top of the najdini – posterior Zone occurs a level (an interval of only a few metres), where nearly all of the Upper Campanian Belemnitella disappear. This level coincides with taxonomic changes observed within the co-occurring representatives of genus Belemnella.

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The Belemnella stratigraphy of the Campanian-Maastrichtian boundary; a new methodological and taxonomic approach

Remin Z.

Acta Geologica Polonica

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2012

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Vol. 62, no. 4

495-533

EN

The taxonomy and stratigraphy of the Upper Campanian and Lower Maastrichtian belemnites from the Vistula (central Poland) and Kronsmoor (northern Germany) sections are revised on the basis of new collections from the Vistula section as well as a reinvestigation of the classic collection of Schulz from the Kronsmoor section. For the taxonomic description a new biometric procedure is proposed, which can be applied to both the genera Belemnella and Belemnitella. For the species-level taxa recognition the Artificial Neural Networks method, the self-organizing Kohonen algorithm, was implemented. This new taxonomic and methodological approach enabled the recognition of nine species of the genus Belemnella. Five of them can be assigned to the existing species B. lanceolata, B. longissima, B. inflata, B. obtusa and B. vistulensis. However, the species concept differs from that applied by Schulz (1979). As a consequence, the stratigraphic ranges of these species are modified. Four species are left in open nomenclature and represent possibly new species. Future studies may reveal that they might be assigned to East European forms from Ukraine or Russia. The species of Belemnella recognized are placed into the stratigraphic framework based on the standard ammonite and inoceramid bivalve zonations, especially those recognized in the Vistula section. The newly proposed belemnite zonation for the Vistula and Kronsmoor sections is correlated via inoceramids with the standard GSSP at Tercis, France, in order to identify the base of the Maastrichtian Stage. The Campanian/Maastrichtian boundary as defined in Tercis is placed here at the base of the newly defined B. obtusa and B. vistulensis Zones ["obtusa/vistulensis"] - thus it is markedly higher than the traditional boundary based on the FAD of representatives of the genus Belemnella - This new boundary coincides well with a distinct turnover of belemnite guard morphology and represents one of the most important points in the early evolutionary history of Belemnella. Three belemnite zones defined by their lower boundaries are recognized in the Campanian/Maastrichtian interval, in addition to three subzones recognized within the B. obtusa Superzone. The B. lanceolata and B. inflata zones as understood here are referred to the Upper Campanian [Tercis definition]. The B. obtusa Zone is subdivided into three subzones, viz.: Belemenlla vistulensis, Belemnella sp. G and Belemnella sp. F, which are referred to the Lower Maastrichtian [Tercis definition]. The fast evolving species of Belemnella enable the proposal of a biostratigraphic scheme with a resolution that is higher than those based on inoceramid bivalves and ammonites - the longevity of a belemnite zone could be as low as 200Ky.

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Early Late Campanian ammonite fauna from Busko Zdrój (Nida Trough, southern Poland)

Machalski M., Kennedy W. J., Kin A.

Acta Geologica Polonica

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2004

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Vol. 54, no. 4

447-471

EN

Sixteen ammonite taxa are recorded from four temporary exposures of lower Upper Campanian deposits in the town of Busko Zdrój, NE limb of the Nida Trough, southern Poland. These are: Phylloceras (Neophylloceras) cf. bodei, Tetragonites obscurus, Desmophyllites sp., Pachydiscus (Pachydiscus) subrobustus, P. (P.) cf. subrobustus, Hoplitoplacenticeras (Hoplitoplacenticeras) dolbergense, H. (H.) sp., H. (Lemfoerdiceras) lemfoerdense, Glyptoxoceras cf. retrorsum, G. sp., Lewyites elegans, Pseudoxybeloceras (Pseudoxybeloceras) riosi, Ps. (Ps.) sp. juv., Baculites sp., Scaphites gibbus, and Trachyscaphites spiniger spiniger. Many specimens lack precise provenance data, but co-occurrence of T. obscurus, P. (P.) subrobustus, H. (H.) dolbergense, H. (L.) lemfoerdense, Ps. (Ps.) riosi, Baculites sp., S. gibbus, and T. s. spiniger is documented from a single opoka bed in one of the exposures.The ammonites allow correlation with standard sections in northern Germany: the ammonite-bearing sequence of Busko Zdrój corresponds to a part of the interval from the basiplana / spiniger to roemeri zones in Lńgerdorf and Kronsmoor (Schleswig-Holstein), and from the stobaei / basiplana to vulgaris / stolleyi zones in the Lehrte West Syncline (Lower Saxony). It can also be correlated with the lower part of the Neancyloceras phaleratum Zone in Vistula valley, central Poland.