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Wyszukujesz frazę "cenomanian" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
On variation in Schloenbachia varians (J. Sowerby, 1817) from the Lower Cenomanian of western Kazakhstan
Autorzy:
Kennedy, W. J.
Powiązania:
https://bibliotekanauki.pl/articles/138676.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ammonites
Schloenbachia
variation
Cenomanian
Cretaceous
Kazakhstan
amonity
mutacja
cenoman
kreda
Kazachstan
Opis:
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.
Źródło:
Acta Geologica Polonica; 2013, 63, 4; 443-468
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Taxonomy and taphonomy of Cenomanian (Upper Cretaceous) nautilids from Annopol, Poland
Autorzy:
Machalski, M.
Wilmsen, M.
Powiązania:
https://bibliotekanauki.pl/articles/139221.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nautilids
condensed deposits
taphonomy
cenomanian
Cretaceous
Annopol
Polska
tafonomia
cenoman
kreda
Polska
Opis:
A nautilid faunule of seven specimens, comprising Eutrephoceras bouchardianum (d’Orbigny, 1840), Cymatoceras deslongchampsianum (d’Orbigny, 1840), and Cymatoceras tourtiae (Schlüter, 1876) is described from a condensed middle Cenomanian interval at Annopol, Poland. C. tourtiae is recorded for the first time in Poland. The studied material consists of reworked phosphatised internal moulds of phragmocones, which may be of early or middle Cenomanian age, given the stratigraphic range of the associated ammonites. The nautilid moulds vary in inferred mode of infilling, and in intensity of abrasion, bioerosion and mineralisation. The sediment entered the phragmocones in two ways: 1) through punctures in the shell, the result of bioerosion or mechanical damage; 2) through siphonal openings by intracameral currents. In contrast to the fossil moulds from the Albian phosphorites of Annopol, which originated via direct precipitation of apatite around and/or inside fossils, the present nautilid moulds seem to have originated through secondary phosphatisation of the initially calcareous moulds. Diversity of taphonomic signatures in nautilid material from the middle Cenomanian interval at Annopol is compatible with the complex, multievent depositional scenario proposed for this level.
Źródło:
Acta Geologica Polonica; 2015, 65, 4; 495-506
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A marker band folgen stratigraphy for the Cenomanian Chalk of England and its extension to northen Germany and France
Autorzy:
Jeans, Christopher Vincent
Powiązania:
https://bibliotekanauki.pl/articles/27323962.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
Cretaceous
cenomanian chalk
folge stratigraphy
marker bands
England
Northern Germany
Northwest France
Cenomanian–Turonian Anoxic Event
kreda
stratygrafia
Anglia
Niemcy Północne
północno-zachodnia Francja
cenoman
turon
Opis:
A novel stratigraphical scheme within the Folge Concept is described for the Cenomanian Chalk of England that is particularly suitable for investigating the regional changes in the lithofacies, diagenesis, geochemistry, and mineralogy of the sediments of the Chalk Sea leading up to the Cenomanian–Turonian Oceanic Anoxic Event. It is based on “isochronous” marker bands defined largely by calcitic macrofossil assemblages, and it avoids problems caused by the poor or non-preservation of ammonite assemblages and lateral changes in chalk lithofacies. Eight folgen are based on one, two, or more marker bands. Their sequences, lithologies and calcitic macrofossil assemblages are described from 33 exposures in the Northern Chalk Province of England. The folgen are named, in ascending order, the Belchford, Stenigot, Dalby, Bigby, Candlesby, Nettleton, Louth and Flixton, after villages in Lincolnshire and Yorkshire, England. The folgen are traced throughout the Transitional and Southern Chalk provinces of England. They are present in the Cenomanian chalk of northern Germany and northwest France. Regionally, an individual folge may display considerable vertical and lateral variation in general lithology and lithofacies whilst still maintaining their defining marker bands. The possibility of further refinement to the scheme is discussed.
Źródło:
Acta Geologica Polonica; 2023, 73, 2; 135--180
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sharpeiceras australe sp. nov., replacement name for Sharpeiceras falloti Kennedy, 2013, non Collignon, 1931
Autorzy:
Kennedy, W. J.
Powiązania:
https://bibliotekanauki.pl/articles/138845.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ammonites
Cenomanian
Cretaceous
Madagascar
South Africa
amonity
cenoman
kreda
Madagaskar
Republika Południowej Afryki
Opis:
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.
Źródło:
Acta Geologica Polonica; 2014, 64, 1; 109-111
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Upper Albian, Cenomanian and Upper Turonian ammonite faunas from the Fahdène Formation of Central Tunisia and correlatives in northern Algeria
Autorzy:
Kennedy, William James
Powiązania:
https://bibliotekanauki.pl/articles/138843.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Ammonites
Cretaceous
Albian
Cenomanian
Turonian
Algeria
Tunisia
amonity
kreda
Alb
cenoman
Turon
Algieria
Tunezja
Opis:
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.
Źródło:
Acta Geologica Polonica; 2020, 70, 2; 147-272
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The stratigraphy of the mid Cretaceous (Albian) Upper Greensand Formation of the Wessex Basin and South West England, UK
Autorzy:
Gallois, R.
Owen, H.
Powiązania:
https://bibliotekanauki.pl/articles/139028.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stratigraphy
Upper Greensand Formation
Cretaceous
Devon
Dorset
Wessex
Albian Stage
Cenomanian Stage
sequence stratigraphy
stratygrafia
formacja
kreda
dewon
alb
cenoman
Opis:
The Upper Greensand Formation, mostly capped by the Chalk, crops out on the edges of a broad, dissected plateau in Devon, west Dorset and south Somerset and has an almost continuous outcrop that runs from the Isle of Purbeck to the Vale of Wardour in south Wiltshire. The Formation is well exposed in cliffs in east Devon and the Isle of Purbeck, but is poorly exposed inland. It comprises sandstones and calcarenites with laterally and stratigraphically variable amounts of carbonate cement, glauconite and chert. The sedimentology and palaeontology indicate deposition in marginal marine-shelf environments that were at times subject to strong tidal and wave-generated currents. The formation of the Upper Greensand successions in the region was influenced by penecontemporaneous movements on major fault zones, some of which are sited over E-W trending Variscan thrusts in the basement rocks and, locally, on minor faults. Comparison of the principal sedimentary breaks in the succession with the sequence boundaries derived from world-wide sea-level curves suggests that local tectonic events mask the effects of any eustatic changes in sea level. The preserved fauna is unevenly distributed, both laterally and stratigraphically. Bivalves, gastropods and echinoids are common at some horizons but are not age-diagnostic. Ammonites are common at a few stratigraphically narrowly defined horizons, but are rare or absent throughout most of the succession. As a result, the age of parts of the succession is still poorly known.
Źródło:
Acta Geologica Polonica; 2018, 68, 2; 161-180
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Redox conditions, glacio-eustasy, and the status of the Cenomanian-Turonian Anoxic Event: new evidence from the Upper Cretaceous Chalk of England
Autorzy:
Jeans, Christopher V.
Wray, David S.
Williams, C. Terry
Bland, David J.
Wood, Christopher J.
Powiązania:
https://bibliotekanauki.pl/articles/1835600.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Cretaceous
Cenomanian–Turonian Anoxic Event
eustatic lithocycles
glacial associations
redox conditions
cerium anomalies
carbon isotopes
NW Europe
Japan
kreda
cenoman
turon
asocjacje
redoks
izotopy węgla
północno-zachodnia Europa
Japonia
Opis:
The nature of the Cenomanian–Turonian Oceanic Anoxic Event (CTOAE) and its δ13 C Excursion is considered in the light of (1) the stratigraphical framework in which the CTOAE developed in the European shelf seas, (2) conclusions that can be drawn from new detailed investigations of the Chalk succession at three locations in England, at Melton Ross and Flixton in the Northern Province where organic-rich ‘black bands’ are present, and at Dover in the Southern Province (part of the Anglo-Paris Basin) where they are absent, and (3) how these conclusion fit in with the present understanding of the CTOAE. The application of the cerium anomaly method (German and Elderfield 1990) at Dover, Melton Ross and Flixton has allowed the varying palaeoredox conditions in the Chalk Sea and its sediments to be related to the acid insoluble residues, organic carbon, δ18O (calcite), δ13C (calcite), δ13C (organic matter), Fe 2+ and Mn2+ (calcite), and P/TiO2 (acid insoluble residue). This has provided evidence that the initial stages of the δ13C Excursion in England were related to (1) a drop of sea level estimated at between 45 and 85 metres, (2) influxes of terrestrial silicate and organic detritus from adjacent continental sources and the reworking of exposed marine sediments, and (3) the presence of three cold water phases (named the Wood, Jefferies and Black) associated with the appearance of the cold-water pulse fauna during the Plenus Cold Event. Conditions in the water column and in the chalk sediment were different in the two areas. In the Northern Province, cerium-enriched waters and anoxic conditions were widespread; the δ13C pattern reflects the interplay between the development of anoxia in the water column and the preservation of terrestrial and marine organic matter in the black bands; here the CTOAE was short-lived (~0.25 Ma) lasting only the length of the Upper Cenomanian Metoicoceras geslinianum Zone. In the Southern Province, water conditions were oxic and the δ13C Excursion lasted to the top of the Lower Turonian Watinoceras devonense Zone, much longer (~1.05 Ma) than in the Northern Province. These differences are discussed with respect to (1) the Cenomanian–Turonian Anoxic Event (CTAE) hypothesis when the ocean-continent-atmosphere systems were linked, (2) limitations of chemostratigraphic global correlation, and (3) the Cenomanian-Turonian Anoxic Event Recovery (CTOAER), a new term to define the varying lengths of time it took different oceans and seas to recover once the linked ocean-continent-atmosphere system was over. The possibility is considered that glacio-eustasy (the glacial control hypothesis of Jeans et al. 1991) with the waxing and waning of polar ice sheets, in association with the degassing of large igneous provinces, may have set the scene for the development of the Cenomanian-Turonian Anoxic Event (CTAE).
Źródło:
Acta Geologica Polonica; 2021, 71, 2; 103-152
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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