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Showing 1 to 20 of 36 for “"Cenomanian"”.
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The Late Cenomanian Anoxic Event; implications for foraminiferal evolution
This study investigates the effect of the late Cenomanian Oceanic Anoxic Event (OAE) on the planktonic and benthonic foraminifera. On the former, the OAE was the cause of major extinctions within the population, the return to pre-OAE oxygen levels permitting recolonization of the vacated niches. On …
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Palynological investigations of Cenomanian chalks and marls from England
… analysis of chalk and marl samples from Cenomanian sections sampled at high resolution has yielded largely diverse and abundant, well-preserved microplankton assemblages. Four sections have been investigated, three from the Dover-Folkestone Warren area, south-east England and the fourth …
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Cyclostratigraphy And Sedimentation Of The Cenomanian-Turonian Tuscaloosa Marine Shale
<p>A cyclostratigraphic and geochemical analysis was conducted on the basal high resistivity zone of the Tuscaloosa Marine Shale to determine if orbital forcing is apparent in mineralogical data suites. Geochemical data suites obtained via x-ray diffraction from five cored wells located near the …
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High-precision U/Pb dating of the Cenomanian-Turonian boundary Kaiparowits Plateau, Utah
The massive marine species turnover at the Cenomanian-Turonian boundary is associated with Oceanic Anoxic Event 11 (OAE II) and is often identified by an increase of a13C in the carbon isotopic record. A high-precision chronology of the Cenomanian- Turonian boundary is needed to better constrain …
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Characterization of Cenomanian-early Turonian bentonites in southwestern Saskatchewan through lithostratigraphy and chemostratigraphy analysis
… X-bentonite). This thesis outlines studies of Cenomanian-early Turonian bentonite across southwestern Saskatchewan, with an aim not only to document these, but to rigorously test whether bentonite can help in refining the regional stratigraphic framework of an area. Specifically, bentonite …
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Foraminiferal and stable isotope investigation of the Cenomanian-Turonian extinction and oceanic anoxic event
… global change, particularly around the Cenomanian-Turonian Boundary (CTB) (93.5 Ma). The mid-Cretaceous is considered to mark a period of intense global warming related to widespread tectonic activity, leading to periods of high sea level and no polar ice. This had great effects on the …
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High-Precision ID-TIMS U-Pb Zircon Geochronology of Three Cenomanian Bentonites from the Western Canada Foreland Basin
… extensive bentonites have been 1 mapped in Cenomanian strata and traced into the U.S. portion of the basin where relationships to globally correlated ammonite zones can be determined. The X, A-X and Bighorn River bentonites provide important calibration points for the Cenomanian Stage. …
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Phytoplankton productivity and Milankovitch Cycles in the Cenomanian-Turonian Bridge Creek member of the Greenhorn Formation in southeastern Colorado
Statistical analyses of palynomorph assemblages from the Upper Cretaceous Bridge Creek Member (Greenhorn Formation) near Pueblo, Colorado suggest that the micritic limestone/organic rich-shale cycles of the Bridge Creek may have been caused by a combination of fluctuating primary productivity and …
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Sedimentary and ecosystem response to Late Cretaceous (Cenomanian - Turonian) paleoenvironmental events along the eastern margin of the Western Interior Seaway, Canada.
… bonebeds are particularly abundant within the Cenomanian-aged strata of the Western Interior Sedimentary Basin’s eastern margin. The major control for their accumulation is interpreted to be related to the timing and magnitude of sea-level fluctuations. Bioclasts are interpreted to be …
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Quantitative palynological analyses of Albian-Cenomanian (Lower to Upper Cretaceous) strata in the Sverdrup Basin: Insights into paleoecology, paleoclimatology and palynostratigraphy
… of terrestrial palynomorphs from Albian to Cenomanian (Lower to Upper Cretaceous), Sverdrup Basin strata reveal a landscape with wet lowlands inhabited by Pteridophytina and Bryophyta, with cooler, moist uplands inhabited by a variety of conifer plants. A humid and temperate climate …
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Cretaceous ostracoda of the super family Cytheracea from Iraq, their biostratigraphy and correlation with adjacent regions
… and between Iraq and neighbouring countries. The Cenomanian-Santonian ostracods of the superfamily Cytheracea were studied in detail from five wells in central and southern Iraq (East Baghdad Well-3, South Rumaila Well-104, Safawi Well-1, Ghalaisan Well-1, and Kifl Well-2). 5 families, 6 …
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A seismic stratigraphic analysis and petroleum system characterization of the cretaceous sequence in central Walvis basin, offshore Namibia
… of the study area. Source rocks deposited in Cenomanian to Turonian period, based on well data and modelling the Cenomanian-Turonian marine source rock is in the early maturity window with total organic carbon (TOC) levels ranging from 0.63% to 5.86%, averaging at 2.02% in the study area. …
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Palaeoenvironmental analysis of the upper Cenomanian and lower Turonian limestone beds in the Sergipe Basin, northeastern Brazil, based on microfacies analysis, micropalaeontology and stable isotopes
Die Kalksteinschichten des oberen Cenoman- unteren Turon (mittlere Kreide) des Sergipe Beckens in Nordost-Brasilien, wurden bezüglich des Paläoenvironments und der Mikrofazies untersucht. Die Mikrofauna wurde auf ihre biostratigraphische Verwendbarkeit analysiert und zur Interpretation des …
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Foraminiferal biostratigraphy and palaeoecology of the Albian to Santonian (Cretaceous) of Bornholm, Denmark
… phases are recognised in the Early Albian, Early Cenomanian and Late Cenomanian-Early Turonian. The Coniacian interval overall shows stable outer shelf water depths, whilst the Late Coniacian-Santonian is probably characterised by an initial phase of increasing water depth followed by a probably …
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Geochemical signatures of black shales deposited during Oceanic Anoxic Event 2 (Cenomanian/Turonian) in the tropical Atlantic (Demerara Rise, ODP Leg 207) and in northern Germany (Wunstorf
Diese Studie präsentiert eine anorganisch-geochemische Untersuchung von zwei Sedimentabfolgen des Ozeanischen Anoxischen Ereignisses 2 (OAE 2) unterschiedlicher paläogeografischer Standorte. Am Demerara Rise (ODP Leg 207; tropischer Atlantik) sind die Sedimente, die während OAE 2 abgelagert wurden, …
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POPULATION DYNAMICS AND GEOCHEMISTRY OF BENTHIC AND PLANKTONIC FORAMINIFERA TO INTERPRET THE PALEOCEANOGRAPHIC CHANGES ACROSS THE CENOMANIAN-TURONIAN OCEANIC ANOXIC EVENT 2 AT LOW AND HIGH LATITUDES
… throughout the Earth’s history, namely the Cenomanian-Turonian Oceanic Anoxic Event 2 (OAE 2). It is globally marked by a positive δ13C excursion due to the deposition and burial of large amounts of organic matter in the ocean. The exact causes of OAE 2 are still studied but it is understood …
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High precision U/Pb geochronology on the Cenomanian Dakota Formation, Utah : implications for paleobotany and the transgression of the Western Interior Seaway preceding Oceanic Anoxic Event 2
The Dakota Formation was deposited during the Cenomanian, a time when the Western Interior Seaway spanned much of North America. The Dakota Formation contains a rich record of plant and animal fossils. Key to understanding their importance, it is imperative to precisely place the Dakota Formation …
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The sedimentology, palaeoecology and stratigraphy of cretaceous rocks in N.W. Scotland
… foraminifera) indicates a latest-Albian to IVlid-Cenomanian age for the Morvern Greensand Formation; a Late Cenomanian age for the Gribun Chalk Formation, and an Early - IVliddle Turonian age for the Str2thaird Limestone Formation. The most refined biostratigraphical range for the Beinn Iadain …
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The Middle to Late Cretaceous microbiostratigraphy (foraminifera) and lithostratigraphy of the Cauvery Basin, Southeast India
… ( I ) in the late Albian and (2) from the late Cenomanian to mid-Turonian, when anoxic conditions developed in the Basin. These anoxic events record major taxonomic changes in the planktonic foraminiferal assemblage. The study shows that the anoxic events had a major affect on the microfaunal …
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Palaeoecology and taxonomy of the macrobenthic fauna from the Upper Cretaceous Ajlun Group, southern Jordan
The Upper Cretaceous Ajlun Group (Cenomanian-Turonian) of southern/south-eastern Jordan has been analysed in 15 detailed sections with thicknesses between 40 m and 200 m. Taxonomic, palaeoecological, taphonomic, and sedimentological aspects were taken into account. During the early Upper Cretaceous …
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