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1

Stratigraphy and palaeoenvironments in the upper Turonian to lower Coniacian of the Saxonian Cretaceous Basin (Germany) - insights from calcareous and agglutinated foraminifers

Besen Richard M., Achilles Mareike, Alivernini Mauro, Voigt Thomas, Frenzel Peter, Struck Ulrich

Acta Geologica Polonica

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2022

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Vol. 72, no. 2

159--186

EN

Upper Turonian to lower Coniacian marls of the Strehlen Formation of the Graupa 60/1 core were investigated for their foraminiferal content to add stratigraphical and palaeoenvironmental information about the transitional facies zone of the Saxonian Cretaceous Basin. Further comparison with foraminiferal faunas of the Brausnitzbach Marl (Schrammstein Formation) were carried out to clarify its relationship to the marls of the Graupa 60/1 core. Tethyan agglutinated marker species for the late Turonian to early Coniacian confirm the proposed age of the marls of the Graupa 60/1 core and the Brausnitzbach Marl. The palaeoenvironment of the marls reflects middle to outer shelf conditions. The maximum flooding zones of genetic sequences TUR6, TUR7 and CON1 could be linked to acmes of foraminiferal species and foraminiferal morphogroups. In general, a rise of the relative sea-level can be recognised from the base to the top of the marls of the Graupa 60/1 core. While agglutinated foraminiferal assemblages suggest a generally high organic matter influx and variable but high productivity in the Graupa 60/1 core, the Brausnitzbach Marl deposition was characterized by moderate productivity and a generally shallower water depth.

2

On some Turonian and Coniacian ammonites from central Colombia

Kennedy William James

Acta Geologica Polonica

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2021

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Vol. 71, no. 3

259--285

EN

The rich collections of Turonian and Coniacian ammonites from Colombia, housed in the University of California Museum of Paleontology, Berkeley, are described, with 20 species recognized, referred to the genera Reymenticoceras Kennedy, 2018, Vascoceras Choffat, 1898, Fagesia Pervinquière, 1907, Wrightoceras Reyment, 1954a, Subprionocyclus Shimizu, 1932, Subprionotropis Basse, 1951, Prionocycloceras Spath, 1926, Barroisiceras de Grossouvre, 1894, Forresteria Reeside, 1932, Niceforoceras Basse, 1948, Peroniceras de Grossouvre, 1894, Gauthiericeras de Grossouvre, 1894, Protexanites Matsumoto, 1955, and Metaptychoceras Spath, 1926. One species, Reymenticoceras ornatum, is new. Most of the species described can be assigned to the substages and ammonite zones recognized in Western Europe.

3

Upper Albian, Cenomanian and Upper Turonian ammonite faunas from the Fahdène Formation of Central Tunisia and correlatives in northern Algeria

Kennedy William James

Acta Geologica Polonica

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2020

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Vol. 70, no. 2

147--272

EN

Over 130 species are documented from the Upper Albian, Cenomanian and Upper Turonian Fahdène Formation and correlatives in Central Tunisia and northern Algeria, based on material described by Henri Coquand (1852, 1854, 1862, 1880), Léon Pervinquière (1907, 1910), Georges Dubourdieu (1953), Jacques Sornay (1955), and new collections. The material consists predominantly of limonitic nuclei, together with adults of micromorphs. There is no continuous record, and a series of faunas are recognised that can be correlated with the zonation developed in Western Europe. These are the Upper Albian Ostlingoceras puzosianum fauna, Lower Cenomanian Neostlingoceras carcitanense and Mariella (Mariella) harchaensis faunas, the upper Lower to lower Middle Cenomanian Turrilites scheuchzerianus fauna, Middle Cenomanian Calycoceras (Newboldiceras) asiaticum fauna, Upper Cenomanian Eucalycoceras pentagonum fauna, and the Upper Turonian Subprionocyclus neptuni fauna. Two new micromorph genera are described, Coquandiceras of the Mantelliceratinae and Cryptoturrilites of the Turrilitinae. Most of the taxa present have a cosmopolitan distribution, with a minority of Boreal, North American and endemic taxa.

4

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.

5

Guettardiscyphia zitti sp. n. - a remarkable hexactinellid sponge from the Lower Turonian of the Bohemian Cretaceous Basin

Vodrážka R.

Geological Quarterly

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2017

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Vol. 61, No. 3

632--640

EN

This paper describes a new hexactinosidan hexactinellid Guettardiscyphia zitti sp. n. on the basis of a detailed study of 279 specimens from 12 localities in the southern part of the Bohemian Cretaceous Basin. All the studied material comes from the basal Bílá Hora Formation (Lower Turonian). The geology and palaeontology of the sponge-bearing strata at studied locations exhibit identical palaeoenvironmental settings: 1 - transgressive character of sediments with low sedimentation rates, 2 - presence of submarine swells formed by crystalline basement, 3 - hemipelagic sedimentation below the storm-wave base, and 4 - the presence of proliferating diverse sponge faunas with subordinate accompanying macrofaunal remains.

6

Mosasauroid predation on an ammonite – Pseudaspidoceras – from the Early Turonian of south-eastern Morocco

Gale A. S., Kennedy W. J., Martill D.

Acta Geologica Polonica

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2017

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Vol. 67, no. 1

31--46

EN

A juvenile specimen of the ammonite Pseudaspidoceras from the Early Turonian of the Goulmima area in the Province of Er-Rachida in south-eastern Morocco shows clear evidence of predation by a tooth-bearing verte-brate. Most of the body chamber is missing, as a result of post-burial compactional crushing. The adapertural part of the shell on the left flank of the surviving fragment of body chamber bears six circular punctuations; the right flank four. These are interpreted as the product of a single bite by a mosasauroid, probably a Tethysaurus. The taxonomy of the Goulmima Pseudaspidoceras is discuused in an appendix.

7

Coilopoceras inflatum Cobban and Hook, 1980, a United States Western Interior ammonite from the Upper Turonian of the southern Corbières, Aude, France

Melchior P., Bilotte M., Kennedy W. J.

Acta Geologica Polonica

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2017

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Vol. 67, no. 1

121--134

EN

A newly discovered ammonite faunule from the Padern region of the southern Corbières in southern France includes representatives of typical northwest European Upper Turonian species Subprionocyclus cf. neptuni (Geinitz, 1850) and Lewesiceras cf. woodi Wright 1979, tethyan/ northwestern Pacific species Phyllopachyceras cf. ezoense (Yokoyama, 1890), Anagaudryceras involvulum (Stoliczka, 1865) and, Desmoceras (Pseudouhligella) sp., together with Coilopoceras inflatum Cobban and Hook, 1980, a species previously known only from New Mexico in the United States, where it is regarded as Middle Turonian. The faunule occurs above one with Romaniceras (R.) mexicanum Jones, 1938 and Coilopoceras springeri Hyatt, 1903, also originally described from New Mexico and northern Mexico, and recently described from the Uchaux massif in Vaucluse in southern France. The records suggest that the base of the Upper Turonian may be drawn at different, higher level in the United States Western Interior than in Europe. The coming together of these mixed faunal elements may be a result of high sea levels, and changing oceanic circulation patterns.

8

A North American ammonite fauna from the late Middle Turonian of Vaucluse and Gard, southern France: the Romaniceras mexicanum, Prionocyclus hyatti and Coilopoceras cf. springeri association

Amédro F., Robaszynski F., Matrion B., Devalque C.

Acta Geologica Polonica

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2016

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Vol. 66, no. 4

729--736

EN

An unusual, exotic, ammonite fauna including Romaniceras mexicanum Jones, 1938, Prionocyclus hyatti (Stanton, 1894) and Coilopoceras cf. springeri Hyatt, 1903 is recorded from the late Middle Turonian of Vaucluse and Gard, southern France. It is the first record of this ammonite association outside the Gulf Coast region and the Western Interior of the United States of North America. Up to present, these species were considered as endemic to the Western Interior sea-way. The migration of numerous ammonites from North America to western Europe during the late Middle Turonian suggests it is linked to a transgressive event or to a short sea-level high.

9

Turonian (Upper Cretaceous) inoceramid bivalves of the genus Mytiloides from the Sredna Gora Mountains, north-western Bulgaria

Dochev D.

Acta Geologica Polonica

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2015

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Vol. 65, no. 1

101--119

EN

The inoceramid bivalves of the genus Mytiloides, from the Turonian (Upper Cretaceous) of the Sredna Gora Mts (north-western Bulgaria), are studied. The material comes from three sections: Izvor, Filipovtsi, and Vrabchov dol. Eight species are described taxonomically, with one left in open nomenclature: M. cf. mytiloides (Mantell, 1822), M. mytiloidiformis (Tröger, 1967), M. incertus (Jimbo, 1894), M. scupini (Heinz, 1930), M. herbichi (Atabekian, 1969), M. striatoconcentricus (Gümbel, 1868), M. labiatoidiformis (Tröger, 1967) and M. carpathicus (Simionescu, 1899). Mytiloides incertus and Mytiloides scupini are index species for the eponymous Upper Turonian inoceramid biozones

10

Turonian ammonite faunas from the southern Corbières, Aude, France

Kennedy W. J., Bilotte M., Melchior P.

Acta Geologica Polonica

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2015

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Vol. 65, no. 4

437--494

EN

The Turonian successions of the southern Corbières comprise three transgressive-regressive cycles in which ammonites occur in three intervals. The lowest comes from the glauconitic basal transgressive unit of the first cycle, and comprises 21 species, including Kamerunoceras douvillei (Pervinquière, 1907), Kamerunoceras turoniense (d’Orbigny, 1850), Spathites (Jeanrogericeras) revelerianus (Courtiller, 1860), Spathites (Jeanrogericeras) combesi (d’Orbigny, 1856), Mammites nodosoides (Schlüter, 1871), Mammites powelli Kennedy, Wright and Hancock, 1987, Fagesia tevestensis (Péron, 1896), Neoptychites cephalotus (Coutiller, 1860), Thomasites rollandi (Thomas and Péron, 1889), Wrightoceras wallsi Reyment, 1954, and Choffaticeras (Choffaticeras) quaasi (Péron, 1904). This is a Lower Turonian assemblage referred to the Mammites nodosoides Zone, although the possibility that elements from the preceding Fagesia catinus Zone are also present cannot be excluded. The fauna from the transgressive glauconitic interval of the succeeding cycle comprises nine species, including Romaniceras (Romaniceras) mexicanum Jones, 1938, Romaniceras (Yubariceras) ornatissimum (Stoliczka, 1864), Pseudotissotia galliennei (d’Orbigny, 1850), Collignoniceras woollgari (Mantell, 1822) sensu lato, Coilopoceras springeri Hyatt, 1903, and Eubostrychoceras (Eubostrychoceras) saxonicum (Schlüter, 1872). They indicate the Middle Turonian Romaniceras (R.) mexicanum and R. (Y.) ornatissimum zones. The highest fauna, from the Marnes supérieurs de Saint-Louis of the Saint-Louis syncline, is: Subprionocyclus sp. juv., Prionocyclus sp. and Worthoceras cf. rochatianum (d’Orbigny, 1850). The Subprionocyclus are minute individuals that resemble S. bravaisianus (d’Orbigny, 1841), and suggest the presence of the lower Upper Turonian bravaisianus Zone.

11

Late Turonian ammonites from Haute-Normandie, France

Kennedy W. J., Gale A. S.

Acta Geologica Polonica

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2015

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Vol. 65, no. 4

507--524

EN

Upper Turonian chalks of Haute-Normandie yield a distinctive ammonite fauna within the Subprionocyclus neptuni ammonite Zone and the Plesiocorys (Sternotaxis) plana echinoid Zone. Well-localised material all comes from the phosphatic fauna of the Senneville 2 Hardground that marks the boundary between the Formation de Senneville and the Életot Member of the succeeding Formation de Saint-Pierre-en-Port. The association is dominated by Lewesiceras mantelli Wright and Wright, 1951, accompanied by Mesopuzosia mobergi (de Grossouvre, 1894), Lewesiceras woodiWright, 1979, Subprionocyclus hitchinensis (Billinghurst, 1927), Subprionocyclus branneri (Anderson, 1902), Subprionocyclus normalis (Anderson, 1958), Allocrioceras nodiger (F. Roemer, 1870), Allocrioceras billinghursti Klinger, 1976, Hyphantoceras reussianum (d’Orbigny, 1850), Sciponoceras bohemicum bohemicum (Fritsch, 1872), and Scaphites geinitzii d’Orbigny, 1850. The fauna represents the Hyphantoceras reussianum Event of authors, elements of which have been recognised on the north side of Tethys from Northern Ireland to the Mangyschlak Mountains of western Kazakstan, a distance of more than 3,500 kilometres.

12

Lithistid spicules in the sediments of the Turonian Variegated Shale in the Silesian Nappe, Polish Outer Carpathians

Okoński S., Górny Z., Bąk M., Bąk K.

Geology, Geophysics and Environment

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2014

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Vol. 40, no. 1

33--48

EN

Turbiditic silty and sandy intercalations in the Turonian Variegated Shale from the Silesian Nappe (Polish Outer Carpathians) contain numerous sponge spicules among siliciclastic fine-grained particles. The highest amount of spicule admixture is nearly 50%. In such layers, they create spiculitic sublitharenite microfacies. These sponge spicules contain forms belonging mostly to the Lithistida group (97% of morphotypes), with a small admixture of spicules from the Hexactinellidae group. Tetraclones with a high content of different types of triaenes dominate among desmas, what indicates the dominance of sponges from subfamily Tetracladina. The preservation state of spicules is generally poor. The Variegated Shale deposits that contain the sponge spicules were accumulated in a deep sea basin, below the calcium compensation depth. Most probably, the spicules were derived from loose material accumulated earlier in various parts of the basin slopes, from which they were exhumed and again redeposited by turbidity currents during the Turonian times.

13

Foraminifera and Late Cenomanian-Turonian biostratigraphy of the northern palaeobiogeographic district of Western Siberia

Podobina Vera

Geologos

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2013

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Vol. 19, No. 3

201--227

EN

The study of 114 core samples from seven borehole sections of the Van-Eganskaya area in the central part of Western Siberia yielded sufficient data to investigate the Late Cenomanian-Turonian foraminifers, palaeoenvironments, and the Late Cenomanian-Turonian biostratigraphy of this poorly studied area. Two Late Cenomanian foraminifer zones were established, viz. a (lower) Saccammina micra - Ammomarginulina sibirica Zone and an (upper) Trochammina wetteri tumida - Verneuilinoides kansasensis Zone. They reflect changes in the species composition of the foraminifer assemblages and lithology of the host rocks of the Uvatskian Horizon. In the lower part of the upper zone, beds with Gaudryinopsis nanushukensis elongatus are present. The changes in the species composition and lithology of the upper Cenomanian resulted from water-depth variations during the Boreal transgression. Two distinct assemblages and two homonymous zones, viz. the (lower) Gaudryinopsis angustus and the (upper) Pseudoclavulina hastata zones occur in the Turonian clayey cap-rocks of the superimposed Kuznetsovskian Horizon. Comparison of the Late Cenomanian-Turonian assemblages from the West-Siberian and Canadian provinces of the same Arctic palaeobiogeographical realm shows that the West-Siberian species are the same as, and closely related to, Canadian taxa, along with geographical subspecies. This comparison allows a detailed correlation, which results in a precise dating of the foraminifer zones.

14

Inoceramid and foraminiferal record and biozonation of the Turonian and Coniacian (Upper Cretaceous) of the Mangyshlak Mts., western Kazakhstan

Walaszczyk I., Kopaevich L. F., Beniamovski V. N.

Acta Geologica Polonica

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2013

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Vol. 63, no. 4

469--487

EN

The Turonian and Coniacian (Upper Cretaceous) of the Mangyshlak Mts., western Kazakhstan, yielded a rich and relatively complete inoceramid bivalve record. The faunas and their succession correspond to those known from central and eastern Europe, allowing the zonation established in the latter areas to be applied in a virtually identical form. The gaps in the record of the group in Mangyshlak stem from the regional hiatuses in the geological record in the area and do not reflect any biogeographical differences between eastern and central-western Europe. Planktonic foraminifera are rare. Four successive interval range zones can be distinguished: in ascending stratigraphic order, the Helvetoglobotrunaca helvetica, Marginotruncaca pseudolinneiana, Marginotruncana coronata, and Concavotruncana concavata zones. Their correlation with the inoceramid zonation and, consequently, with the chronostratigraphic scheme, is demonstrated. The zonation and chronostratigraphic subdivision as applied in Mangyshlak may easily be applied to other areas of the peri-Caspian region (Caucasus, Tuarkyr, Kopet-Dagh, SE margin of the East-European Craton).

15

Foraminifers and stable isotope record of the Dubivtsi chalk (upper Turonian, Western Ukraine): palaeoenvironmental implications

Dubicka Z., Peryt D.

Geological Quarterly

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2012

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Vol. 56, No 1

199-214

EN

A combined micropalaeontological and stable isotope study of the Dubivtsi chalk in the Western Ukraine indicates its middle late Turonian age. One long-term and clearly distinguishable positive excursion of the isotope curve (d1318

16

Testing the congruence of the macrofossil versus microfossil record in the Turonian-Coniacian boundary succession of the Wagon Mound-Springer composite section (NE New Mexico, USA)

Walaszczyk I., Lees J., Peryt D., Cobban W., Wood C.

Acta Geologica Polonica

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2012

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Vol. 62, no. 4

581-594

EN

The Turonian-Coniacian boundary succession from the Wagon Mound-Springer composite section in the US Western Interior shows a virtually identical macrofaunal record to that revealed in the proposed candidate Coniacian GSSP in the Salzgitter-Salder-Slupia Nadbrzezna composite section in central Europe, with easy identification in both regions of the base of the Coniacian Stage, as defined by the first appearance of the inoceramid bivalve species, Cremnoceramus deformis erectus (Meek). The macrofaunal boundary definition is additionally confirmed by the foraminiferal and nannofossil data, demonstrating the high potential of the inoceramid marker for the base of the Coniacian. The former claims about distinct diachroneity between macrofossil and microfossil dates in the trans-Atlantic correlations, resulted from methodological deficiencies, and have no factual basis.

17

Facies and integrated stratigraphy of the Upper Turonian (Upper Cretaceous) Grossberg Formation south of Regensburg (Bavaria, southern Germany)

Niebuhr B., Richardt N., Wilmsen M.

Acta Geologica Polonica

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2012

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Vol. 62, no. 4

595-615

EN

The Upper Turonian Grossberg Formation of the Regensburg area (Danubian Cretaceous Group, Bavaria, southern Germany) has a mean thickness of 20-25 m and consists of sandy bioclastic calcarenites and calcareous sandstones which are rich in bryozoans, serpulids and bivalves (oysters, rudists, inoceramids). Eight facies types have been recognized that characterize deposition on a southward dipping homoclinal ramp: the inner ramp sub-environment was characterized by high-energy sandwave deposits (sandy bioclastic rud- and grainstones, bioclastic sandstones) with sheltered inter-shoal areas. In mid-ramp settings, bioturbated, glauconitic, calcareous sand- and siltstones as well as bioturbated, bioclastic wacke- and packstones predominate. The carbonate grain association of the Grossberg Formation describes a temperate bryomol facies with indicators of warm-water influences. An inferred surplus of land-derived nutrients resulted in eutrophic conditions and favoured the heterozoan communities of the Grossberg Ramp. Carbon stable isotope geochemistry cannot significantly contribute to the stratigraphic calibration of the Grossberg Formation due to the depleted and trendless bulk-rock [delta^13]C values, probably resulting from a shallow-water aquafacies with depleted [delta^13]C DIC values and low [delta^13]C values of syndepositional and early diagenetic carbonate phases. However, strongly enriched skeletal calcite [delta^13]C values support a correlation of the Grossberg Formation with the mid-Late Turonian positive Hitch Wood isotope event (Hyphantoceras Event of northern Germany). This interpretation is supported by biostratigraphic data and a range from the Mytiloides striatoconcentricus Zone into the lower My. scupini Zone is indicated by inoceramid bivalves. Both the base and top of the Grossberg Formation are characterized by unconformities. Sequence boundary SB Tu 4 at the base is a major regional erosion surface (erosional truncation of the underlying Kagerhoh Formation in the Regensburg area, fluvial incision at the base of the Seugast Member of the Roding Formation in the Bodenwohr area towards the north and northeast). It is suggested that this unconformity corresponds to a major sea-level drop recognized in many other Cretaceous basins below the Hitch Wood or Hyphantoceras Event. The transgression and highstand of the Grossberg Formation is concomitant to the deposition of the fluvial Seugast Member and the onlap of the marginal-marine. Veldensteiner Sandstein. onto the Frankische Alb. The unconformity at the top of the Grossberg Formation (late Late Turonian SB Tu 5) is indicated by a ferruginous firm-/ hardground and an underlying zone of strongly depleted [delta^13]C values. The abrupt superposition by deeper marine marls of the lower Hellkofen Formation (uppermost Turonian.Lower Coniacian) may be connected with inversion tectonics at the southwestern margin of the Bohemian Massif.

18

Wstępne dane o nagromadzeniu jeżowców z rodzaju Conulus w profilu dolnego turonu Glanowa (niecka miechowska)

Borszcz T., Gajerski A., Rakociński M., Szczepańczyk A.

Przegląd Geologiczny

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2008

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Vol. 56, nr 7

552-556

EN

An interesting phenomenon of echinoid accumulation occurring in the Lower Turonian (Mytiloides labiatus Zone) at Glanów village (Miechów Upland) is the main topic of the paper. The bed investigated consists of poorly cemented sandy-marly limestones with thickness of about 30 cm. The accumulation of echinoids is older than that of documented in Wielkanoc which is of middleto-late Turonian age and situated in the same region under study. Apart from a dominant echinoid species Conulus subrotundus Mantell represented by adult and juvenile forms that are dispersed in the bed, the second echinoid species -a regular form Salenocidaris granulosa (Woodward)-has also been noted. Additionally, the skeletal elements of crinoids, ophiuroids, asteroids, as well as bryozoans, annelids, poriferans and shark teeth have also been found in the bed under study. Preliminary observations indicate that the origin of the echinoid accumulation corresponds well with the Conulus bed from the Wielkanoc quarry as a result of luxuriant development of echinoids and complex sedimentological, paleoecological and tectonic factors.

19

Development of the Turonian Conulus Lagerstätte in the Wielkanoc quarry, Miechów Upland (South Poland)

Olszewska-Nejbert D.

Annales Societatis Geologorum Poloniae

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2005

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Vol. 75, No 2

199-210

EN

Turonian sandy limestones and organodetrital limestones exposed in the Wielkanoc quarry, Miechów Upland, South Poland, lie on Oxfordian massive limestones, truncated with an abrasion surface. The bed situated ca. 2.5 m above the abrasion surface contains a parautochthonous and monotypic assemblage of the species Conulus subrotundus Mantell, 1822; thus the concentration can be referred to as the Conulus Lagerstätte. The microfacies analysis of the Conulus Lagerstätte indicates its development to have been determined by the existence of eco-events producing an increased population of Conulus subrotundus, and of sedimentological factors, that is waning of the loose sediment from the sea floor and erosion of the consolidated deposit rich in the earlier fossilised echinoids. The episodes of material accumulation, its consolidation and erosion in high-energy environment (action of bottom current) led to the increase of amount of echinoids as the intraclasts according to the model of lag sediment deposition.

PL

W kamieniołomie Wielkanoc (Wyżyna Miechowska), położonym na granicy Jury Polskiej i Niecki Miechowskiej (Fig. 1) odsłania się 10 m profil utworów oerodkowego i górnego turonu (Fig. 2), leżących na powierzchni abrazyjnej, oecinającej oksfordzkie wapienie skaliste. Utwory turońskie są wykształcone w dolnej części profilu w postaci wapieni piaszczysto-organodetrytycznych, organodetrytycznych lub piaszczystych, podczas gdy w górnej przeważają wapienie organodetrytyczne. Profil turonu kończy warstwa wapieni pelitowych z twardym dnem w stropie, nad którym leżą wapienie piaszczysto-glaukonitowe koniaku. Około 2,5 m nad powierzchnią abrazyjną znajduje się warstwa z wyraźnie większą frekwencją jeżowców (Fig. 3, 4), które stanowią paraautochtoniczny i monotypowy zespół gatunku Conulus subrotundus Mantell, 1822. Nagromadzenie jeżowców Conulus w jednej warstwie o znacznym rozprzestrzenieniu horyzontalnym pojawia się tylko raz w profilu turonu kamieniołomu Wielkanoc. Wykonane badania pokazały niejednorodną budowę warstwy z jeżowcami (Fig. 5–8). W obrębie tła skalnego występują intraklasty bez jeżowców, intraklasty, w których jeżowiec stanowi część intraklastu oraz jeżowce. Tło skalne jest packstonem inoceramowym (Fig. 5h, 7F), podobnie jak utwory leżące powyżej warstwy z jeżowcami (Fig. 5i, 8). Intraklasty nie zawierające jeżowców są zbudowane z wakstonu otwornicowo-kalcisferowego z dużą domieszką kwarcu oraz podrzędnie glaukonitu (Fig. 5c, 7B). Litologicznie odpowiadają osadom podoecielającym warstwę z jeżowcami (Fig. 5b, 7A). Intraklasty z jeżowcami charakteryzują się nieco bardziej złożoną budową. Skała otaczająca pancerz wykształcona jest jako wakston otwornicowo-kalcisferowy z dużą domieszką kwarcu oraz podrzędną glaukonitu (Fig. 5d, f; 7D, E). Ten sam rodzaj osadu wypełnia większość pancerzy jeżowców (Fig. 5e, 7E). Znacznie rzadziej spotykane są okazy, gdzie skała wypełniająca pancerz jeżowca w całości jest wakstonem otwornicowo- kalcisferowym bez domieszek kwarcowo-glaukonitowych (Fig. 5g, 7C), lub też wypełnienie pancerza ma charakter mieszany, tzn. część okazu wypełniona jest wakstonem otwornicowokalcisferowym z dodatkiem dużej ilości kwarcu i niewielkiej glaukonitu, zaś pozostała część, tej domieszki jest pozbawiona. Jeżowce nie będące częścią intraklastu wypełnione są wakstonem otwornicowo-kalcisferowym z dużą domieszką kwarcu i niewielk ą glaukonitu. Nieliczne okazy są wypełnione wakstonem otwornicowo-kalcisferowym, który nie zawiera domieszek kwarcowo- glaukonitowych. Obserwacje terenowe i analiza mikrofacjalna pozwoliły stwierdzić, iż do nagromadzenia jeżowców w analizowanej warstwie przyczyniły się czynniki ekologiczne i złożone czynniki sedymentologiczne. Do tych pierwszych należą zdarzenia ekologiczne, kiedy w środowisku stosunkowo niskoenergetycznym powstały optymalne warunki rozwoju Conulus subrotundus Mantell. Na czynniki sedymentologiczne złożyło się zarówno wymywanie świeżo złożonego luźnego osadu jak i erozja już skonsolidowanego osadu, bogatego w sfosylizowane wcześniej jeżowce (Fig. 9). Proces ten polegał na epizodach akumulacji materiału, jego konsolidacji i erozji w środowisku wysokoenergetycznym, co doprowadziło do powstania bruku rezydualnego (ang. lag deposit) składającego się ze sfosylizowanych wczeoeniej jeżowców. Opisane procesy zachodziły na podmorskim progu krakowskim, który funkcjonował jako jednostka paleogeograficzna od turonu po santon. Próg krakowski rozdzielał dwa głębsze baseny, położony na NE basen bruzdy duńsko-polskiej od basenu opolskiego na SW. W generalnie transgresywnych utworach późnej kredy, na progu krakowskim osadzały się utwory płytkowodne. Osadzanie tych utworów było przerywane częstymi epizodami erozji, gdyż próg krakowski, zanim został ostatecznie pogrążony w późnym santonie, podlegał okresowo silnej działalności falowania i prądów dennych.

20

Benthic foraminiferal response to the Cenomanian-Turonian and Cretaceous-Paleogene boundary events

Peryt D.

Przegląd Geologiczny

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2004

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Vol. 52, nr 8/2

827-8

EN

The present paper summarizes previously published results of my studies on the Cenomanian-Turonian and Cretaceous-Paleogene changes in benthic foraminiferal assemblages. The recorded changes indicate that the rate and intensity of restructuring of benthic foraminiferal populations during the Cenomanian-Turonian Boundary Event (CTBE) and Cretaceous-Paleogene Boundary Event (KTBE) strongly depended on the duration and severity of environmental stress. A stepwise extinction within benthic foraminiferal assemblages, a bloom of infaunal and semi-infaunal morphotypes during the CTBE and a relatively long-lasting survival interval (the Whiteinella archaeocretacea chron) most likely reflect the decline in oxygenation level of the bottom waters at the end of the Rotalipora cushmani chron and persistence of these unfavourable conditions during the Whiteinella archaeocretacea chron. A catastrophic type of mass extinction within benthic foraminiferal assemblages, extinction or temporary emigration of most of infaunal morphogroups during the KPBE and a relatively short survival interval are interpreted to be the result of a sudden breakdown in food supply as the consequence of a sudden collapse in primary productivity, probably resulting from the impact of the K-P asteroid.