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1

The Cenomanian heterozoan carbonates in the north-central Alborz, north-east Kelardasht, north Iran

Kavoosi Mohammad Ali, Ezoji Neda

Geological Quarterly

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2021

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Vol. 65, No. 3

art. no. 37

EN

Detailed field surveys, petrographic investigation and SEM and EDS analyses have been used to evaluate Cenomanian glauconitic heterozoan carbonates in north-east Kelardasht, north-central Alborz, north Iran. Lithofacies and microfacies analyses led to recognition of six microfacies types related to the inner-, mid- and outer-ramp facies belts of a carbonate ramp. The heterozoan nature of these carbonates is inferred from a predominance of echinoderms associated with calcispheres, planktonic foraminifers, a lack of ooid grains, and a low carbonate production rate, together with a high content of glauconite grains and prevailing high-Mg calcite mineralogy. Petrographic and SEM studies reveal that glauconite filling skeletal grains retains the shape and morphology of host grains, signifying an authigenic origin at low sedimentation rates and slightly reducing conditions. SEM images show cauliflower and rosette structures associated with well-developed lamellae indicating an authigenic origin of evolved glauconite grains. Our findings are compatible with a nutrient-rich waters and palaeoecological stress related to relative sea-level rise and eutrophic conditions, which contributed to the generation of these heterozoan carbonates despite the hot greenhouse conditions during the Cenomanian in the north-central Alborz Mountains.

2

First Upper Cretaceous dinosaur track assemblage from Jordan (Middle East) : preliminary results

Klein Hendrik, Gierliński Gerard, Lallensack Jerns N., Abu Hamad Abdalla, Al-Mashakbeh Habes, Alhejoj Ikhlas, Konopka Marcin, Błoński Marcin

Annales Societatis Geologorum Poloniae

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2020

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Vol. 90, No. 3

331--342

EN

Dinosaur tracks from Jordan (Middle East) have only been briefly reported in geological overview papers and books. We present here the first description and documentation of Jordanian dinosaur tracks based on a new tracksite from the south-central part of the country. The track-bearing strata belong to marginal marine (tidal flat) deposits of the Na’ur Formation (Upper Cretaceous, Cenomanian). This unit largely consists of well-bedded limestones, dolomites and marls that contain abundant marine invertebrate fossils such as bivalves, ammonites and foraminifers. The dinosaur ichnofauna occurs on four different levels and comprises abundant theropod tracks and trackways as well as isolated sauropod and ornithopod tracks. Theropod trackways consist of two different morphotypes. Morphotype 1 is tridactyl (26 cm pes length) and with a broad, but short metatarsal area and resembles the ichnogenus Picunichnus from the Lower Cretaceous (Albian) of Argentina. Morphotype 2 (36 cm pes length) has extensive and narrow metatarsal impressions continuously occurring along regularly-spaced trackways. This suggests either a plantigrade movement of the trackmaker or reflects preservational factors. By their over-all-shape with thin digits, Morphotype 2 resembles described penetrative tracks suggesting a strong influence of the substrate. Sauropod tracks are relatively small (40 cm pes length) and show low heteropody with a kid-ney-shaped manus imprint, pointing to a Sauropodichnus-like form. The single ornithopod pes track (18 cm in length) is similar to material described as Ornithopodichnus from the Lower Cretaceous of Korea. Due to the incomplete material of sauropod and ornithopod prints, no concrete assignment is given to this material and further study is needed. The presence of dinosaur tracks proves a temporary subaerial exposure of the surface whereas the main part of the Na’ur Formation is dominated by subaqueous activity of marine faunas.

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

Charakterystyka wód geotermalnych cenomańskiego systemu wodonośnego na pograniczu SE części niecki miechowskiej i zapadliska przedkarpackiego

Gorczyca G., Chowaniec J., Gągulski T.

Przegląd Geologiczny

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2017

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Vol. 65, nr 11/1

962--967

EN

Wider exploration of geothermal waters of the Cenomanian aquifer system at the south-eastern border of the Miechów Basin and the Carpathian Basin was possible due to research carried out in boreholes OB-I and OB-II in 2016. Geothermal water occurring in sand and Cenomanian sandstone was found in both boreholes. The waters differ in mineralization and content of specific constituents, and the outflow temperature. In borehole OB-I occurs Cl—Na, I type water with the mineralization of 9.83 g/dm3and the outflow temperature of 27.2°C, whereas in borehole OB-II the water was Cl-Na, S type with a mineralization of 12.08 g/dm3 and outflow temperature of 21.5°C.

5

Trans-Tethyan correlation of the Lower-Middle Cenomanian boundary interval; southern England (Southerham, near Lewes, Sussex) and Douar el Khiana, northeastern Algeria

Kennedy W. J., Gale A. S.

Acta Geologica Polonica

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2017

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Vol. 67, no. 1

75--108

EN

A 480 m section of marls with widely separated levels of nodular limestone in the Fahdene Formation north of Bou Khadra in Tebessa Province, northeastern Algeria, spans the Lower/Middle Cenomanian boundary. A total of 30 ammonite species are present, of which two: Forbesiceras reversum and Calycoceras (Newboldiceras) algeriense are new. The fauna allows recognition of the Northwest European upper Lower Cenomanian Mantelliceras dixoni Zone, the succeeding lower Middle Cenomanian Cunningtoniceras inerme Zone, the Acanthoceras rhotomagense Zone and its subzones of Turrilites costatus and Turrilites acutus. The sequence of index species occurs in the same order in both north-eastern Tunisia and the Southerham Grey Pit in Sussex (and indeed elsewhere in North-west Europe), indicating these to be robust assemblage zones and subzones that can be recognised on both the north and south sides of the Tethys. Other occurrences of taxa that are common in both sections and regions are markedly different, and include the co-occurrence of Cunningtoniceras inerme (Pervinquière, 1907) with Acanthoceras rhotomagense (Brongniart, 1822) in the costatus Subzone in north-eastern Algeria and central Tunisia, the extension of Acompsoceras renevieri (Sharpe, 1857) into the lower Middle Cenomanian in north-eastern Tunisia, whilst the acme of Turrilites scheuchzerianus Bosc, 1801, is in the dixoni Zone in Northwest Europe, and in the inerme Zone in northeasten Algeria and adjacent parts of Central Tunisia. These differences are not a result of collection failure or non-preservation, but must rather reflect environmental controls on occurrence and abundance.

6

Facies changes in the Cenomanian (Cretaceous) of the northwestern Elbe Valley near Dresden (Saxony, Germany)

Tröger K. -A.

Acta Geologica Polonica

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2017

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Vol. 67, no. 1

135--144

EN

The Upper Cretaceous of the Elbe Valley in Saxony and the erosion outliers west of it mark an Upper Cretaceous NW-SE-running strait between the Westsudetic Island in the NE and the Mid-European Island to the west. This street connected the NW-German-Polish Basin in the north and the Bohemian Cretaceous Basin (and adjacent regions of the Tethys) in the south. However, post-Cretaceous erosion north of Meißen removed any Upper Cretaceous deposits but erosion outliers at Siebenlehn and especially north of the Forest of Tharandt proof the presence of a marly through silty belt in this area. Three transgressions (base of uppermost Lower to Middle Cenomanian, base of Upper Cenomanian and base of the geslinianum Zone in the mid-Upper Cenomanian) have taken place. The sedimentation was influenced by the topography of the mentioned islands and by movements at structural lines in the Proterozoic and Palaeozoic basement. During the early Late Cenomanian, a marly-silty sedimentation (Mobschatz Formation) in the north existed besides sandy sedimentation in the south (Oberhäslich Formation). The transgression at the base of the geslinianum Zone caused the final submergence of island chains between Meißen, Dresden and Pirna, and a litho- and biofacies bound to cliffs and submarine swells formed. A silty-marly lithofacies, a mixed sandy-silty lithofacies (Dölzschen Formation) and a sandy lithofacies in the south (Sächsisches Elbsandsteingebirge) co-existed during the latest Cenomanian. The first mentioned biofacies yields a rich fauna mainly consisting of oysters, pectinids, rudists, and near-shore gastropods accompanied by echinids and, in some cliffs, teeth of sharks. The Pennrich fauna (Häntzschel 1933; Uhlig 1941) especially consists of the very common serpulids Pyrgopolon (P.) septemsulcata and Glomerula lombricus (formerly Hepteris septemsulcata and G. gordialis).

7

The late Cenomanian oyster Lopha staufferi (Bergquist, 1944) – the oldest ribbed oyster in the Upper Cretaceous of the Western Interior of the United States

Hook S. C., Cobban W. A.

Acta Geologica Polonica

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2016

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Vol. 66, no. 4

609--626

EN

Lopha staufferi (Bergquist, 1944) is a medium-sized, ribbed, Late Cretaceous oyster with a slightly curved axis and a zigzag commissure; it appears suddenly and conspicuously in upper Cenomanian rocks in the Western Interior Basin of the United States. At maturity, the ribs on both valves thicken into steep flanks that allow the oyster to increase interior volume without increasing its exterior footprint on the seafloor. Lopha staufferi is the first (earliest) ribbed oyster in the Late Cretaceous of the Western Interior, but has no ancestor in the basin. It disappears from the rock record as suddenly as it appeared, leaving no direct descendent in the basin. In the southern part of the basin where it is well constrained, L. staufferi is restricted stratigraphically to the upper Cenomanian Metoicoceras mosbyense Zone (= Dunveganoceras conditum Zone in the north). Lopha staufferi has an unusual paleogeographic distribution, occurring in only two, widely scattered areas in the basin. It has been found at several localities near the western shoreline of the Late Cretaceous Seaway in west-central New Mexico and adjacent Arizona, and in localities 1,900 km (1,200 mi) to the northeast near the eastern shoreline in northeastern Minnesota, but nowhere in between. In west-central New Mexico and adjacent Arizona, L. staufferi is a guide fossil to the Twowells Tongue of the Dakota Sandstone.

8

Successive stages of calcitization and silicification of Cenomanian spicule-bearing turbidites based on microfacies analysis, Polish Outer Carpathians

Bąk B., Górny Z., Bąk K., Wolska A., Stożek B.

Annales Societatis Geologorum Poloniae

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2015

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Vol. 85, No. 1

187--203

EN

Mid-Cretaceous turbidites with large proportions of sponge spicules are widely distributed in the Silesian Nappe of the Outer Carpathians, giving rise to diversified types of sediments, from spiculites to spicule-bearing siliciclastics and calcarenites. Part of this succession, Middle–Late Cenomanian in age, was transformed into cherts. A microfacies study showed that these turbidite sediments underwent several stages of calcitization and silicification, which took place during Mid-Cretaceous times in different sedimentary environments, i.e., on a northern shelf bordering the Silesian Basin and on a deep sea floor. The first diagenetic changes were related to changes to the biotic components of the turbidite layers, dominated by siliceous sponge spicules. This process, which took place in the spiculitic carbonate mud on the shelves, was related to the calcitization of sponge spicules. Calcareous clasts and calcified skeletal elements also were corroded by bacteria. After transportation down the slope, the biogenic and siliciclastic particles were deposited below the carbonate compensation depth. Taphonomic processes on the basin floor and alternating phases of carbonate and silica cementations, recrystallization and dissolution occurred in these sediments and were related to the diversification in composition of successive turbidite layers. Silicification was related to the formation of quartz precipitates as fibrous chalcedony or microcrystalline quartz, which were derived from the earlier dissolution of amorphous silica, originating mostly from siliceous sponge spicules and radiolarian skeletons. However, a source of silica from hydrothermal vents was also possible. The initial silica precipitation could have taken place in a slightly acidic environment, where calcite was simultaneously dissolved. A number of silicification stages, visible as different forms of silica precipitate inside moulds after bioclasts, occur in the particular turbidite layers. They were related to changes in various elements of the pore-water profile after descending turbidity-current flows. A very low sedimentation rate during the Middle–Late Cenomanian in the Silesian Basin may have favoured the sequence of initial calcitization and silicification stages of the turbidite sediments.

9

Sharpeiceras australe sp. nov., replacement name for Sharpeiceras falloti Kennedy, 2013, non Collignon, 1931

Kennedy W. J.

Acta Geologica Polonica

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2014

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Vol. 64, no. 1

109--111

EN

Sharpeiceras australe sp. nov. is proposed as the replacement name for Sharpeiceras falloti Kennedy, 2013, non Collignon, 1931, from the Lower Cenomanian of the Morondavo Basin, Madagascar.

10

On variation in Schloenbachia varians (J. Sowerby, 1817) from the Lower Cenomanian of western Kazakhstan

Kennedy W. J.

Acta Geologica Polonica

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2013

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Vol. 63, no. 4

443--468

EN

An assemblage of 94 specimens of Schloenbachia varians (J. Sowerby, 1817) from the Lower Cenomanian Sharpeiceras schlueteri Subzone of the Mantelliceras mantelli Zone of the Besakty section in the Mangyshlak Mountains of western Kazakhstan includes 26 complete adults that range from to 59–174 mm in diameter. No size-related dimorphism was detected in the assemblage, which shows wide, continuous intraspecific variation. This is described in terms of five formae; from robust to gracile these are: ventriosa, varians sensu stricto, subtuberculata, intermedia, and subplana. The ratio of robust (ventriosa + varians sensu stricto) to gracile (subtuberculata + intermedia + subplana) individuals is 34% to 66%. The reference specimens of the formae and their synonyms are described and illustrated, and related to the Besakty material. The modification of adult body chamber ornament of all formae is documented, and Jakeiceras Cooper and Owen, 2011 is shown to be based on an adult of a passage form between forma subtuberculata and forma intermedia. The differences between Lower Cenomanian S. varians, lower Middle Cenomanian S. coupei (Brongniart, 1822), and upper Middle and lower Upper Cenomanian S. lymensis Spath, 1926b are described and illustrated.

11

Thin-bedded strata and tuning effect as causes of seismic data anomalies in the top part of the Cenomanian sandstone in the Grobla–Rajsko–Rylowa area (Carpathian foreland, Poland)

Marzec P., Pietsch K. J.

Geological Quarterly

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2012

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Vol. 56, No. 4

691--710

EN

A high-amplitude anomaly in seismic signal, i.e. a bright-spot, which is the main direct hydrocarbon indicator, may also occur due to interference between the reflected signals from the top and base of a thin bed (the tuning effect). In such settings the main problem is to distinguish amplitude anomalies associated with lithological changes or changes in gas saturation from anomalies originating from the tuning effect. We provide a method of interpreting the composite seismic signal produced by the interference between reflections. Such reflections occur along the top of the Cenomanian sandstone in the area of the Grobla–Rajsko–Rylowa 3-D seismic dataset (southern Poland). The non-standard method presented here is based on interpretation of seismic data which was rotated by 270°. The results of seismic modelling were used to develop criteria for interpretation of such data. These criteria are based on the difference between information carried by the peak-to-trough amplitude and that by the total amplitude of rotated seismic data. The difference was used to define the transfer function and to remove the high-amplitude anomalies caused by the constructive interference between the reflected signals from the top and bottom of the thinning stratum. The final outcome of the study was a map showing the seismic amplitude response at the top Cenomanian reflector unaffected by the tuning effect. The map shows the extent of the area where high-amplitude anomalies do not correspond with changes in thickness and petrophysical parameters within the top part of the Cenomanian. These anomalies are caused by a lateral increase in thickness of the Turonian and/or an increase in the velocity within the bottom part of the Senonian (Coniacian) strata. The map can be used to determine precisely the boundaries of the Rajsko and Rylowa gas reservoirs as well as to locate the potential extension of the reservoir zone to the east of the Rylowa 6 borehole.

12

Inorganic geochemical records of local palaeoenvironmental variability in the Jaworki Formation (Upper Cretaceous) of the Niedzica Succession, Pieniny Klippen Belt (Western Carpathians)

Wójcik-Tabol P.

Studia Geologica Polonica

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2008

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Vol. 131

269-280

EN

The Cenomanian sequence of marls and marly shales interbedded by black shales (Jaworki Formation) from the Niedzica Succession was investigated. These organic carbon-rich horizons may correspond to the event of global anoxity OAE 1d. Major and trace element profiles mirror changing environments of deposition of black shales. In black shales, the content of SiO2, Al2O3, Fe2O3, K2O, TiO2, P2O5 increases at the expense of CaO. All samples are characterised as mixtures of terrigenous- detrital matter with varying amount of calcium carbonate. A good correlation between SiO2, Al2O3, K2O, TiO2, and the correlation with the minor elements Zr, Rb and Nb, point to the detrital origin of these elements. Detrital input was rather scarce. The high trace element/Al ratios in the black shales can be explained either by the adsorption onto organic matter or through the sulphides precipitation. Some black shale-samples are poorer in transitional metals. The studied sediments were deposited under oxic/suboxic conditions interrupted by irregular anoxic periods resulted from expansion of oxygen minimum zone (OMZ).

13

When the "primitive" shark Tribodus (Hybodontiformes) meets the "modern" ray Pseudohypolophus (Rajiformes) : the unique co-occurrence of these two durophagous Cretaceous selachians in Charentes (SWFrance)

Vullo R., Neraudeau D.

Acta Geologica Polonica

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2008

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Vol. 58, no. 2

249-255

EN

The palaeoecology and palaeobiogeography of two Cretaceous selachian genera, Tribodus BRITO & FERREIRA, 1989 and Pseudohypolophus CAPPETTA & CASE, 1975, are briefly discussed. These two similar-sized taxa developed an analogous pavement-like grinding dentition, characterized by massive teeth with a rhomboidal to hexagonal occlusal surface. Although both genera appear to have been euryhaline forms, the hybodont Tribodus occurred in fresh/brackish water habitats (e.g. deltas) to shallow marine lagoons, whereas the ray Pseudohypolophus lived in brackish water to coastal marine environments. Palaeobiogeographically, their global distribution displays two distinct but adjoined areas, with Tribodus being present in the northern part of Gondwana (Brazil and North Africa), and Pseudohypolophus occurring on both sides of the North Atlantic (North America and Western Europe). However, the two genera coexisted during Cenomanian times within a small overlap zone, localized in western France. A trophic competition may have arisen from this situation between these two selachians belonging to the same trophic guild. This peculiar situation is well documented within the Cenomanian transgressive series of Charentes (SW France), where a turnover between the two forms is observed (replacement of Tribodus by Pseudohypolophus).

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The middle-upper Cenomanian of Zilly (Sachsen-Anhalt, northern Germany) with remarks on the Pycnodonte Event

Wilmsen M., Voigt T.

Acta Geologica Polonica

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2006

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Vol. 56, no. 1

17-31

EN

A detailed stratigraphic log of the 28 m thick Cenomanian succession at Zilly (Sachsen-Anhalt) is presented. The succession is composed of 11 m of middle Cenomanian hemi-pelagic marl-limestone alternations ("Planer Limestones") grading into 15 m of upper Cenomanian calcareous pelagites ("Poor rhotomagense Limestones") unconformably overlain by 1,5 m of red-coloured marly clays and limestones ("Rotplaner"). The proof of the interregional marker beds of the Pycnodonte Event at the 11 m level, the Facies Change at 26 m, and the base of the plenus Bed at 26,9 m allow a bio-/chronostratigraphic correlation of these levels with the middle/upper Acanthoceras jukesbrownei Zone (upper middle Cenomanian), the Calycoceras (Proeucalycoceras) guerangeri/Metoicoceras geslinianum Zone transition, and the lower Metoicoceras geslinianumZone, respectively (middle upper Cenomanian).Litho-/microfacies and sequence stratigraphic analyses indicate an overall increase of pelagic influence up to the Facies Change. This retrogradational trend was shortly interrupted by the Pycnodonte Event, the base of which correlates with the late middle Cenomanian sequence boundary SB Ce IV and the succeeding transgressive surface. The Facies Change indicates a significant mid-late Cenomanian sea-level fall (sequence boundary SB Ce V), followed by more shallow water Rotplaner deposition. The Pycnodonte Event is very thick and proximal in character at Zilly. Its monospecific oyster fauna consists of small pycnodonteines assigned to Pycnodonte (Phygraea) vesicularis (LAMARCK) vesiculosa (J. SOWERBY), a secondarily free-lying oyster which lived as a "cup-shaped recliner".The patchy occurrence of the oysters, the sorting and partial damage of valves prior to final burial along with significant supply of terrigenous materials suggest episodically elevated water energy and strong environmental stress during deposition of the Pycnodonte Event. This situation promoted colonization of the sea-floor by, and reproductive success of the inferred eurytopic oyster. The Pycnodonte Event is a classic example of an "onlapping bioevent", the formation of which was controlled by different factors such as sea-level rise, terrigenous influx, environmental stress, and preferential preservation.

15

The Trawne Member (Albian-Cenomanian, Pieniny Klippen Belt, Carpathians) : a new insight into its foraminiferal assemblages and biostratigraphy

Pióro K.

Studia Geologica Polonica

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2005

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Vol. 124

237-248

EN

Detailed micropalaeontological analysis of samples from the Pasieczny and Trawne stream sections has been undertaken. Twenty five species including seventeen planktonic taxa have been identified. The Rotalipora ticinensis - Planomalina praebuxtorfi new biozone has been proposed. In the Pasieczny Stream section, turbiditic sedimentation commenced during the Early Cenomanian (Rotalipora appenninica Zone). The new biozone R. greenhornensis has been established. The Rotalipora reicheli - Rotalipora greenhornensis Zone, based on coexistence of both nominal species was recognized. The studied foraminiferal associations have confirmed palaeobathymetrical associa- tions B1-B2 (middle part of the continental slope).

16

A Middle Cenomanian foraminiferal assemblage from the Nowe Rybie section (Żegocina Tectonic Window, Subsilesian Unit, Polish Outer Carpathians)

Machaniec E., Gasiński M. A., Ślączka A., Leśniak T.

Studia Geologica Polonica

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2005

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Vol. 124

249-258

EN

The Żegocina Tectonic Window is the most eastward located tectonic window of the Lanckorona-Żegocina Zone in the Polish Outer Carpathians and represents the slope parts of the Silesian basin and intrabasinal uplifted zones of the Subsilesian Unit. Upper Cretaceous and Palaeocene variegated marls, typical deposits of the studied part of the basin, are intercalated with the so-called Rybie beds (local sediments of siliciclastic submarine fans). A Middle Cenomanian foraminiferal assemblage (Rotalipora reicheli Zone) is here described from these sediments. The assemblage contains numerous planktonic (epipelagic and bathypelagic) foraminiferids, which is rather unique within the "Flysch" type assemblages. A middle slope palaeodepth is suggested as the depositional environment, based on benthic and planktonic foraminiferal associations.

17

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.

18

The mid-Cenomanian eustatic low

Hancock J.

Acta Geologica Polonica

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2004

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Vol. 54, no. 4

611-627

EN

Through much of the earlier part of the Middle Cenomanian the sea-levels in western Asia, northern Europe and the Western Interior of the U.S.A. were lower than during the later Early Cenomanian and most of the later Middle Cenomanian. In north-west Europe the first sign of this Mid-Cenomanian Eustatic Low was just before the end of the Zone of Cunningtoniceras inerme. There was then an abrupt and strong fall of sea-level at the base of Milankovitch couplet C 1, early in the Subzone of Turrilites costatus. Sea-level continued to be low through couplets C 1 to C 3 for some 60,000 years: this is the Mid-Cenomanian Regressive Trough. In western Germany it has been distinguished as the Primus Event. In north Texas and the Western Interior of the U.S.A. the Trough occurred in the Zone of Conlinoceras tarrantense which can be dated as 95.78 [plus-minus] 0.61 Ma.A later regressive trough occurred at the start of the Subzone of Turrilites acutus, which is marked by the Mid-Cenomanian Event in Germany. The overall lower sea-level from late in the Zone of C. inerme to early in the Subzone of T. acutus is the Mid-Cenomanian Eustatic Low. It lasted some 300,000 years.

19

Middle Cenomanian ammonites from the type section of the Sanandinovo Formation of northern Bulgaria

Kennedy W., Jolkicev N.

Acta Geologica Polonica

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2004

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Vol. 54, no. 3

369-380

EN

The type section of the Sanandinovo Formation between the villages of Sanandinovo and Novachene in northern Bulgaria has yielded numerous ammonites from packages 7-9 of the sequence recognised by previous authors. The assemblage is: Tetragonites subtimotheanus WIEDMANN, 1962, Puzosia (Puzosia) mayoriana (D.ORBIGNY, 1841), Acanthoceras jukesbrownei (SPATH, 1926), Protacanthoceras tuberculatum tuberculatum THOMEL, 1972, Calycoceras (Newboldiceras) asiaticum asiaticum (JIMBO, 1894), C. (N.) asiaticum spinosum (KOSSMAT, 1897), C. (N.) planecostatum (KOSSMAT, 1897), Calycoceras (Proeucalycoceras) picteti WRIGHT & KENNEDY, 1990, and Scaphites equalis J. SOWERBY, 1813. The assemblage indicates the upper Middle Cenomanian Acanthoceras jukesbrownei Zone of Western Europe. We have seen no evidence for either older or younger Cenomanian ammonite zones from the sequence.

20

Cenomanian through Lower Coniacian events in the Upper Cretaceous of Saxony, Germany

Troger K.

Acta Geologica Polonica

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2004

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Vol. 54, no. 4

629-638

EN

The event sequence recognised in the Cenomanian through basal Coniacian (Late Cretaceous) of the Elbe Valley is compared with the event stratigraphic scheme worked out in NW Germany. The following events, recognised originally in Lower Saxony, and subsequently in other Cretaceous areas of north-western Europe, were found in Saxony: Schloenbachia / virgatus eustatoevent (Lower Cenomanian); Chondrites ecoevent, Puzosia eustatoevent and plenus eustatoevent (Upper Cenomanian); hattini ecoevent, Mytiloides ecoevents, hercynicus ecoevent, Hyphantoceras ecoevent, Didymotis ecoevents and waltersdorfensis ecoevent (Turonian); erectus ecoevent, hannovrensis ecoevent, and incostans ecoevent (Lower Coniacian). Both the oxic/anoxic Cenomanian/Turonian boundary event and the facies change at the base of the Metoicoceras geslinianum Zone are recognisable. With the exception of the Mytiloides ecoevents, recorded in all facies types, all the events are well developed only in the marly-silty facies.Local events, specific to the Cretaceous of Saxony are: the Late Cenomanian Pennrich event, known from the Sudetic area, and the Middle Turonian rhynchonellid events, occurring in sandy and transitional facies between Pirna and Bad Schandau.