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Integrated biostratigraphy and palaeoenvironments of the Upper Cretaceous in the Petrich section (Central Srednogorie Zone, Bulgaria)

Pavlishina Polina, Dochev Docho, Wagreich Michael, Koukal Veronika

Acta Geologica Polonica

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2023

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Vol. 73, no. 1

33--62

EN

The Upper Cretaceous succession (Coniacian to lowermost Maastrichtian, with focus on the Campanian) at Petrich, Central Srednogorie Zone in Bulgaria, is described and calibrated stratigraphically based on nannofossils, dinoflagellate cysts and inoceramids. The following standard nannofossil zones and subzones are identified: UC10-UC11ab (middle to upper Coniacian), UC11c-UC12-UC13 (uppermost Coniacian to Santonian), UC14a (lowermost Campanian), UC14bTP-UC15cTP (lower Campanian to ‘middle’ Campanian), UC15dTP-UC15eTP (upper Campanian), UC16aTP (of Thibault et al. 2016; upper part of the upper Campanian), and UC16b (Campanian-Maastrichtian boundary). The base of the Campanian is defined by the FO of Broinsonia parca parca (Stradner) Bukry, 1969 and Calculites obscurus (Deflandre) Prins and Sissingh in Sissingh, 1977 (a morphotype with a wide central longitudinal suture). The Areoligera coronata dinoflagellate cyst Zone (upper lower Campanian to upper upper Campanian) is identified, corresponding to the UC14bTP-UC16aTP nannofossil subzones. The inoceramid assemblage indicates the ‘Inoceramus’ azerbaydjanensis-‘Inoceramus’ vorhelmensis Zone, correlated within the interval of nannofossil subzones UC15dTP-UC15eTP. The composition of the dinoflagellate cyst assemblages and palynofacies pattern suggest normal marine, oxic conditions and low nutrient availability within a distal shelf to open marine depositional environment during the Campanian.

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Inoceramids and associated ammonite faunas from the uppermost Turonian-lower Coniacian (Upper Cretaceous) of the Anaipadi-Saradamangalam region of the Cauvery Basin, south-east India

Walaszczyk I., Kennedy W. J., Paranjape A. R.

Acta Geologica Polonica

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2018

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Vol. 68, no. 4

663--687

EN

The lower (but not lowermost) part of the Upper Cretaceous Anaipadi Formation of the Trichinopoly Group in the area between Kulatur, Saradamangalam and Anaipadi, in the south-western part of the Cauvery Basin in southeast India yielded rich inoceramid and ammonite faunas. The ammonites: Mesopuzosia gaudama (Forbes, 1846), Damesites sugata (Forbes, 1846), Onitschoceras sp., Kossmaticeras (Kossmaticeras) theobald ianum (Stoliczka, 1865), Lewesiceras jimboi (Kossmat, 1898), Placenticeras kaffrarium Etheridge, 1904, and Pseudoxybeloceras (Schlueterella) sp., are characteristic of the Kossmaticeras theobaldianum Zone. The absence of Peroniceras (P.) dravidicum (Kossmat, 1895) indicates the presence of only lower part of this zone, referred to the nominative Kossmaticeras theobaldianum Subzone at the localities studied. The inoceramids present are Tethyoceramus madagascariensis (Heinz, 1933) and Cremnoceramus deformis erectus (Meek, 1877), recorded for the first time from the region. The latter dates the studied interval as early early Coniacian, and allows, for the first time, direct chronostratigraphic dating of the Tethyoceramus madagascariensis Zone, and consequently also of the Kossmaticeras theobaldianum Subzone. As inoceramids occur in the middle part of the ammonite-rich interval, the Kossmaticeras theobaldianum Subzone may be as old as latest Turonian and not younger than early early Coniacian. The base of the Coniacian lies in the lower, but not lowermost part of the Anaipadi Formation. Both inoceramids and ammonites represent taxa known from Madagascar and South Africa.

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Klasyczne stanowiska paleontologiczne górnej kredy zachodniej Ukrainy: historia badań oraz biostratygrafia

Machalski M., Malchyk O.

Przegląd Geologiczny

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2016

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Vol. 64, nr 8

570--576

EN

For a long time, outcrops at Potelych, Nahoryany and Lviv in western Ukraine have been of special interestfor Campanian andMaastrichtian (Upper Cretaceous) palaeontology and biostratigraphy. An overview of studies devoted to these classic sites is presented, including an early account of the locality of Nahoryany in a Polish newspaper, dated 1843. The biostratigraphic position ofthese successions is reviewed, based on recent progress in studies of inoceramid bivalves and ammonites. The succession at Potelych, from where a unique land flora was described at the beginning of the 20th century, represents the upper Campanian “Ino- ceramus” costaecus Zone. The Nahoryany opoka, the source of rich fossil collections that were sent to many European museums in the 19th century, belongs to the lower Maastrichtian Endo- costea typica and Trochoceramus radiosus zones. The so-called Lviv marls correspond to the lower upper Maastrichtian Spyridocera- mus tegulatus Zone. The giant scaphitid ammonites Hoploscaphites quadrispinosus and Acanthoscaphites tridens s. str from Potelych and Nahoryany corroborate the inoceramid-based dating of these successions.

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Encrustation of inarticulate brachiopods on scaphitid ammonites and inoceramid bivalves from the Upper Cretaceous U. S. Western Interior

Landman N. H., Slattery J. S., Harries P. J.

Acta Geologica Polonica

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2016

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Vol. 66, no. 4

645--662

EN

The inarticulate brachiopod Discinisca is a rare faunal element in the Upper Cretaceous of the U.S. Western Interior. We report two occurrences of encrustation of Discinisca on a scaphitid ammonite (scaphite) and several inoceramids from the lower Maastrichtian Baculites baculus/Endocostea typica Biozones of the Pierre Shale at two localities. Six specimens of Discinisca are present on a single specimen of Hoploscaphites crassus from eastcentral Montana. They occur along the furrow at the mature apertural margin. Because the brachiopods are restricted to the margin and do not occur on the rest of the shell, it is likely that they encrusted the ammonite during its lifetime. If so, this implies that the soft body of the scaphite did not cover the outside surface of the aperture, leaving this area vulnerable to epizoan attachment. A total of 13 specimens of Discinisca are also present on four specimens of Cataceramus? barabini from east-central Wyoming. The brachiopods occur in crevices on the outside of the shells and may have encrusted the inoceramids after their death as the shells began to break down and delaminate, resulting from the decomposition of the organic matrix holding them together. Based on the faunal assemblages at both localities, the presence of Discinisca may indicate environments with either low oxygen levels and/or few predators or competitors.

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Palaeontology of the Middle Turonian limestones of the Nysa Kłodzka Graben (Sudetes, SW Poland): biostratigraphical and palaeogeographical implications

Chrząstek Alina

Geologos

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2012

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Vol. 18, No. 2

83--109

EN

The ammonites Lewesiceras peramplum Mantell and ?Lewesiceras sp. are reported from the Upper Cretaceous in the Nysa Kłodzka Graben; they date from the Middle Turonian and ?Coniacian, respectively. The Middle Turonian limestones of the Stara Bystrzyca quarry contain an abundant assemblage of inoceramids (Inoceramus cuvieri Sowerby and I. lamarcki Parkinson) and other bivalves, including oysters, as well as brachiopods and trace fossils. Micropalaeontological data show the presence of foraminifers and siliceous sponge spiculae, bryozoans, ostracods and fragments of bivalves and gastropods. The Middle Turonian calcareous deposits belongs to the upper part of the Inoceramus lamarcki Zone (late Middle Turonian) and were deposited on a shallow, subtidal offshore shelf. They overlie the Middle Turonian Bystrzyca and Długopole Sandstones, which represent foreshore-shoreface delta deposits. The fossil assemblage suggests a moderate- to low-energy, normal-salinity environment with occasionally an oxygen deficit.