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Jianguo Li - One of the best experts on this subject based on the ideXlab platform.
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new biostratigraphic framework for the triassic paleogene in the neo tethys realm of southern xizang tibet china
Journal of Asian Earth Sciences, 2020Co-Authors: Jianguo Li, Yixiao Wu, Jungang Peng, Lin Mu, Bo Xu, Chao ZhangAbstract:Abstract Multifaceted biostratigraphic work on Triassic to Paleogene strata in southern Xizang (Tibet), western China, in the last decades allows a new, refined biochronostratigraphic framework in the Qinghai–Xizang plateau region. Synthesis of the latest biostratigraphic progress is carried out in this paper to build a new integrated biostratigraphic scheme comparable to the international Geological Time Scale. The scheme incorporate key fossils as many of each system, such as ammonites, calcareous Nanofossils, conodonts and foraminifers. Other fossil groups that are helpful for stratigraphic division and interregional correlation are also contained. These include bivalves, miospores and radiolarians, some of which, e.g. radiolarians and miospores, not previously well explored, are now utilised for new zones. Biostratigraphic zones of this new integrative system, especially the Lower Triassic conodonts and ammonites, uppermost Triassic–Lower Jurassic ammonites, Upper Cretaceous planktonic foraminifers and calcareous Nanofossils, correlate well with the international standards. The results are tabulated as four new comprehensive biostratigraphic charts, which, we hope, will provide a new and more reliable foundation for study of the stratigraphy and chronology of Neo-Tethys.
Chao Zhang - One of the best experts on this subject based on the ideXlab platform.
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new biostratigraphic framework for the triassic paleogene in the neo tethys realm of southern xizang tibet china
Journal of Asian Earth Sciences, 2020Co-Authors: Jianguo Li, Yixiao Wu, Jungang Peng, Lin Mu, Bo Xu, Chao ZhangAbstract:Abstract Multifaceted biostratigraphic work on Triassic to Paleogene strata in southern Xizang (Tibet), western China, in the last decades allows a new, refined biochronostratigraphic framework in the Qinghai–Xizang plateau region. Synthesis of the latest biostratigraphic progress is carried out in this paper to build a new integrated biostratigraphic scheme comparable to the international Geological Time Scale. The scheme incorporate key fossils as many of each system, such as ammonites, calcareous Nanofossils, conodonts and foraminifers. Other fossil groups that are helpful for stratigraphic division and interregional correlation are also contained. These include bivalves, miospores and radiolarians, some of which, e.g. radiolarians and miospores, not previously well explored, are now utilised for new zones. Biostratigraphic zones of this new integrative system, especially the Lower Triassic conodonts and ammonites, uppermost Triassic–Lower Jurassic ammonites, Upper Cretaceous planktonic foraminifers and calcareous Nanofossils, correlate well with the international standards. The results are tabulated as four new comprehensive biostratigraphic charts, which, we hope, will provide a new and more reliable foundation for study of the stratigraphy and chronology of Neo-Tethys.
Nicolas Thibault - One of the best experts on this subject based on the ideXlab platform.
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an integrated stratigraphic study across the santonian campanian boundary at bocieniec southern poland a new boundary stratotype candidate
Cretaceous Research, 2017Co-Authors: Zofia Dubicka, Nicolas Thibault, Agata Jurkowska, Mohammad Javad Razmjooei, Krystian Wojcik, Przemyslaw Gorzelak, Ireneusz FelisiakAbstract:Abstract An integrated biostratigraphic (foraminifera, calcareous nannofossils, crinoids), chemostratigraphic (stable carbon isotopes) and magnetostratigraphic study of the Bocieniec section (southern Poland) is presented here. The section presents a continuous and lithologically monotonous sedimentary record across the Santonian–Campanian boundary transition. A large number of macrofossil, foraminiferal and calcareous nannofossil bioevents along with several well-identified carbon-isotope excursions of the upper Santonian and lowermost Campanian are documented. The base of the Campanian is well-constrained by the last occurrence (LO) of the crinoid Marsupites testudinarius , and correlates to the onset of the first δ 13 C positive peak of the Santonian–Campanian Boundary Event (SCBE peak a). A presumable primary Cretaceous paleomagnetic signal highlights the potential presence of the C34N/C33R magnetic reversal although its exact position remains uncertain between peaks a and b of the SCBE. The planktic foraminifer Dicarinella asymetrica is very rare at Bocieniec but a potential LO of this important marker may be recorded in coincidence with peak b of the SCBE. The first occurrence (FO) of calcareous nannofossil Broinsonia parca parca coincides with the lower part of chron C33R and with the early Campanian pilula zone event. A large set of additional nannofossil events and benthic foraminifer events further constrain the stratigraphy of the section and along with the carbon isotopes, allows for correlation with other important sections of the Boreal realm. Although the Bocieniec section is relatively thin and condensed (5.5 m), the successive order of events and presence of all past proposed stratigraphic criteria for the Santonian-Campanian boundary makes it the most complete reference section for this interval at the European and at the global scale. Moreover, this section allows for a precise correlation of the Tethyan and Boreal domains. The Bocieniec section fulfils the geological criteria to be a potential boundary stratotype candidate for the base of the Campanian Stage.
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upper campanian maastrichtian chronostratigraphy of the skaelskor 1 core denmark correlation at the basinal and global scale and implications for changes in sea surface temperatures
Lethaia, 2015Co-Authors: Nicolas Thibault, Kresten Anderskouv, Morten Bjerager, Lars Ole Boldreel, Mads E Jelby, Lars Stemmerik, Finn SurlykAbstract:The lithostratigraphy, calcareous nannofossil biostratigraphy, carbon- and oxygen-isotope stratigraphy and gamma-ray profile are presented for the Skaelskor-1 core, eastern Denmark. The correlation of carbon isotopes to Gubbio (Italy) and ODP Site 762C (Indian Ocean) provides the chronostratigrahical framework of the core through a tie to magnetostratigraphy. Two new carbon-isotope excursions are defined for the uppermost Maastrichtian of the core and prove useful for long-distance correlation. Twenty stratigraphic tie-points are used for correlation of the upper Campanian–Maastrichtian interval by combining carbon-isotope and gamma-ray variations. Significant dissimilarities in the gamma-ray profiles of the Danish Basin cores preclude the sole use of this tool for basin-scale correlations. Bulk oxygen-isotopes and semi-quantitative abundance changes in the warm-water calcareous nannofossil Watznaueria barnesiae and the cool-water Kamptnerius magnificus highlight the following past changes in sea-surface temperatures (SSTs): relatively warm late Campanian SSTs, cooling across the Campanian–Maastrichtian boundary and through the early Maastrichtian, warming across the early–late Maastrichtian transition, cooling in the late Maastrichtian, intense warming in the latest Maastrichtian chron C29r, followed by a very short episode of cooling immediately before the Cretaceous–Palaeogene boundary. The late Campanian–Maastrichtian evolution in sea water temperatures inferred from the Danish Basin is similar to that delineated at tropical latitude oceanic sites.
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upper campanian maastrichtian holostratigraphy of the eastern danish basin
Cretaceous Research, 2013Co-Authors: Finn Surlyk, Lars Stemmerik, Niels H Schovsbo, Poul Schioler, Emma Sheldon, Susanne Rasmussen, Myriam Boussaha, Nicolas ThibaultAbstract:Abstract One of the most expanded upper Campanian–Maastrichtian successions worldwide has been cored in a series of boreholes in eastern Denmark. A high-resolution holostratigraphic analysis of this part of the Chalk Group has been undertaken on these cores, notably Stevns-1, in order to provide a record of changes in chalk facies, water depths and sea-water temperatures. Combined lithological data, a suite of petrophysical logs including gamma ray (GR) logs, nannofossil and dinoflagellate palaeontology, stable carbon isotopes, seismic reflection and refraction sections form the basis for the definition of two new formations and six members, three of which are new, and for recognition of Boreal nannofossil subzones UC15e BP to UC20d BP . The upper Campanian–lowermost Maastrichtian Mandehoved Formation is subdivided into the Flagbanke and Boesdal Members and the Maastrichtian Mons Klint Formation is subdivided into the Hvidskud, Rordal, Sigerslev, Kjolby Gaard Marl and Hojerup Members. The Boesdal and Rordal Members show high GR values and a pronounced chalk-marl cyclicity. The Rordal and the thin Kjolby Gaard Marl Members have a regional distribution and can be traced over most of the Danish Basin, whereas the Hojerup Member is restricted to the easternmost part of Sjaelland. The other members consist of rather featureless white chalk.
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upper campanian maastrichtian nannofossil biostratigraphy and high resolution carbon isotope stratigraphy of the danish basin towards a standard δ13c curve for the boreal realm
Cretaceous Research, 2012Co-Authors: Nicolas Thibault, Lars Stemmerik, Bruno Galbrun, Rikke Harlou, Niels H Schovsbo, Poul Schioler, Fabrice Minoletti, Bodil W Lauridsen, Emma Sheldon, Finn SurlykAbstract:High-resolution carbon isotope stratigraphy of the upper Campanian–Maastrichtian is recorded in the Boreal Realm from a total of 1968 bulk chalk samples of the Stevns-1 core, eastern Denmark. Isotopic trends are calibrated by calcareous nannofossil bio-events and are correlated with a lower-resolution δ13C profile from Rordal, northwestern Denmark. A quantitative approach is used to test the reliability of Upper Cretaceous nannofossil bio-events and provides accurate biohorizons for the correlation of δ13C profiles. The Campanian–Maastrichtian boundary (CMB) is identified through the correlation of dinoflagellate biostratigraphy and δ13C stratigraphy between Stevns-1 and the Global boundary Standard Stratotype-section and Point at Tercis les Bains (SW France), allowing the identification of new chemical and biostratigraphic markers that provide a precise placement of the stage boundary on a regional scale. The boundary interval corresponds to the third phase of a stepwise 0.8‰ negative δ13C excursion, lies in calcareous nannofossil subzone UC16dBP, and encompasses the last occurrence of nannofossil Tranolithus stemmerikii and first occurrence of nannofossil Prediscosphaera mgayae. Fifteen δ13C events are defined and correlated to sixteen reliable nannofossil biohorizons, thus providing a well-calibrated standard high-resolution δ13C curve for the Boreal Realm.
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Bio-magnetochronology for the upper Campanian - Maastrichtian from the Gubbio area, Italy: new results from the Contessa Highway and Bottaccione sections
Newsletters on Stratigraphy, 2012Co-Authors: Silvia Gardin, Nicolas Thibault, Bruno Galbrun, Rodolfo Coccioni, Isabella Premoli-silvaAbstract:A new bio-chronostratigraphic framework is presented for the upper Campanian - Maastrichtian pelagic sediments of the Gubbio area (Bottaccione and Contessa Highway sections, Italy). New planktonic foraminiferal (FO of P. hantkeninoides), calcareous nannofossil (FO of M. prinsii, base acme of M. murus) and magnetostratigraphic data are provided and integrated to construct an age-depth curve based on the recent astronomical calibration of the late Campanian - Maastrichtian magnetic polarity time scale (Husson, D., Galbrun, B., Laskar, J., Hinnov, L. A., Thibault, N., Gardin, S., Locklair, R. E., 2011. Astronomical calibration of the Maastrichtian, Late Cretaceous. Earth and Planetary Science Letters 305, 328-340). All bio-horizons recorded in both sections fall on or are very close to the Line of Correlation (LOC), which testifies to the reliability of biochronologic studies in the Umbria-Marche basin. The proposed age model allows to estimate the sedimentation rates and the ages of calcareous nannofossil and planktonic foraminiferal bio-horizons in both sections. Also, it provides an excellent late Campanian - Maastrichtian reference for sections in the Umbria-Marche area and the entire Tethys. Due to the presence of a ∼425 kyr-long hiatus in Chron C31n of the Bottaccione section, the Contessa Highway section constitutes a more complete late Campanian - Maastrichtian reference for bio-magnetochronology in the Tethyan realm.
Emanuela Mattioli - One of the best experts on this subject based on the ideXlab platform.
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impact of the middle jurassic diversification of watznaueria coccolith bearing algae on the carbon cycle and δ13c of bulk marine carbonates
Global and Planetary Change, 2012Co-Authors: Baptiste Sucherasmarx, Bernard Pittet, Abel Guihou, Fabienne Giraud, Christophe Lecuyer, Pascal Allemand, Emanuela MattioliAbstract:During the Mid Mesozoic Revolution, thought to have started 200 Ma ago (late Triassic), the production of calcium carbonate in the ocean shifted from platform and epicontinental seas to the open ocean, concurrently with the diversification of coccolithophorids. In this regard, the radiation of the coccolith genus Watznaueria during the Middle Jurassic is thought to represent one of the most important steps of this diversification. Nevertheless, the timing of this diversification remains poorly constrained, and its possible impact on global carbon budgets remains unclear. In this study, we present new records of nannofossil fluxes and carbon stable isotope composition from sedimentary deposits of Lower Bajocian age from the Cabo Mondego (Portugal) reference section to further address the possible impact of this diversification on the Middle Jurassic global carbon cycle. Our results show that calcareous nannofossil fluxes increase markedly from the upper part of the Aalenian to the Early Bajocian, coinciding with a 0.75% positive shift in carbon isotope compositions of bulk carbonate. Reconstructions of mass accumulation rates indicate that nannofossil fluxes increased by two orders of magnitude (from 10(9) to 10(11) nannofossils/m(2)/yr) during the corresponding time interval, mainly related to the rise of Watznaueria genus, whose relative abundance jumped from 2% to 20% of the total rock composition. The calculated amount of carbon derived from calcareous nannofossils deposited in the Early Bajocian seas was, however, 10 to 20 times lower than current levels. Mass balance calculations indicate that the increase of nannofossil flux throughout the studied interval was most likely not the main cause of the accompanying isotopic perturbation, suggesting a limited role of the Early Bajocian diversification on the global carbon cycle. Our results show that while the diversification of Watznaueria throughout the Bajocian caused a major increase in the flux of pelagic carbonate to the deep ocean, it was most likely quantitatively insufficient to have a large impact on the global biogeochemistry of the oceans.
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a global event with a regional character the early toarcian oceanic anoxic event in the pindos ocean northern peloponnese greece
Geological Magazine, 2011Co-Authors: N Kafousia, V Karakitsios, Hugh C Jenkyns, Emanuela MattioliAbstract:The Early Toarcian (Early Jurassic, c. 183 Ma) was characterized by an Oceanic Anoxic Event (T-OAE), primarily identified by the presence of globally distributed approximately coeval black organic-rich shales. This event corresponded with relatively high marine temperatures, mass extinction, and both positive and negative carbon-isotope excursions. Because most studies of the T-OAE have taken place in northern European and Tethyan palaeogeographic domains, there is considerable controversy as to the regional or global character of this event. Here, we present the first high-resolution integrated chemostratigraphic (carbonate, organic carbon, delta(13)C(carb), delta(13)C(org)) and biostratigraphic (calcareous nannofossil) records from the Kastelli Pelites cropping out in the Pindos Zone, western Greece. During the Mesozoic, the Pindos Zone was a deep-sea ocean-margin basin, which formed in mid-Triassic times along the northeast passive margin of Apulia. In two sections through the Kastelli Pelites, the chemostratigraphic and biostratigraphic (nannofossil) signatures of the most organic-rich facies are identified as correlative with the Lower Toarcian, tenuicostatum/polymorphum-falciferum/serpentinum/levisoni ammonite zones, indicating that these sediments record the T-OAE. Both sections also display the characteristic negative carbon-isotope excursion in organic matter and carbonate. This occurrence reinforces the global significance of the Early Toarcian Oceanic Anoxic Event.
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pliensbachian early jurassic calcareous nannofossils from the peniche section lusitanian basin portugal a clue for palaeoenvironmental reconstructions
Marine Micropaleontology, 2010Co-Authors: Emanuela Mattioli, Bernard Pittet, Letizia Reggiani, Luis V Duarte, Veiga L De Oliveira, Maria Jose ComasrengifoAbstract:Abstract Quantitative analysis of Early Jurassic calcareous nannofossil assemblages from the Peniche section in Portugal have been performed in order to interpret palaeoenvironmental changes occurring in the Lusitanian Basin during the Late Pliensbachian Davoei, Margaritatus and Spinatum Ammonite Zones. Nannofossil data are compared to already published carbon and oxygen stable isotope data, organic matter content (wt.%Total Organic Carbon, TOC), and biomarker analysis. A significant change in calcareous nannofossil assemblages and species diversity at the transition between the Margaritatus and Spinatum Ammonite Zones matches with the pattern shown by geochemical data. This suggests that a profound change in environmental conditions occurred at that time. In the Davoei and Margaritatus Ammonite Zones, in a context of general sea-level rise, the Lusitanian Basin was characterized by water column stratification that favoured the sedimentation and preservation of organic matter. Biomarkers and oxygen isotope trends suggest that stratification of water masses occurred because of low salinity in surface waters. The shallowest part of the water column, characterized by oligotrophic conditions, was inhabited by the (probable) calcareous dinocyst Schizosphaerella spp., while the deep-dweller Crepidolithus crassus flourished in the lower photic-zone layers. In the Spinatum Ammonite Zone, a regressive trend occurred and a salinity increase is inferred on the basis of oxygen isotope values. Water masses were probably less stratified at that time. The upper photic-zone nannofossil assemblages were still dominated by Schizosphaerella spp. whilst, in the deep photic-zone, Mitrolithus jansae (a Mediterranean taxon) replaced C. crassus (a taxon with NW-European affinity). This pattern may indicate a change in palaeoceanographic conditions related to surface current circulation. The sea-level fall occurring during the Spinatum Ammonite Zone may have resulted in the partial isolation of the Lusitanian Basin from the NW-Europe basins because of the creation of a threshold. Alternatively, tectonic drowning of North African carbonate platforms in the Late Pliensbachian may have promoted better exchanges of nannoplankton between the Lusitanian Basin and the Mediterranean Tethys via the creation of new seaway connections.
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spatial distribution of late pliensbachian early jurassic calcareous nannofossils within the lusitanian basin portugal
Geobios, 2010Co-Authors: Emanuela Mattioli, Letizia Reggiani, Bernard PittetAbstract:Abstract Quantitative analyses of Pliensbachian calcareous nannofossils have been carried out on a proximal-distal transect in the Lusitanian Basin (Portugal). The studied sections Vale Venteiro near Tomar and Peniche represent proximal and distal environments with respect to the emerged land of the Iberian Meseta (to the East). The upper portion of the Vale das Fontes Fm (Davoei and Margaritatus ammonite Zones) is studied in both sections and correlated by means of ammonite and nannofossil integrated biostratigraphy. A careful analysis of the preservation state of nannofossils is performed. Preservation state is moderate to good in the two settings; changes in nannofossil assemblages are therefore considered as primary. Samples were analysed for nannofossil absolute and relative abundances, species diversity and wt%CaCO 3 . The analysis of calcareous nannofossils (absolute abundance, percentage, average abundance) shows changes in the community structure in space (i.e., from proximal to distal), and vertically within the water column. This pattern suggests a partitioning of habitats within the photic zone, and with respect to emerged lands. Proximal environments within the Lusitanian Basin were probably more eutrophic, because of the proximity of emerged lands to the East (Iberian Meseta). This was the source area for nutrients delivered into the basin by river transport. Distal environments were likely characterized by a greater water depth and by a deeper light penetration leading to a relatively more expanded photic zone. The assemblages recorded in the proximal setting exhibit high mean relative abundance of placolith-bearing coccolithophorids ( Lotharingius spp., Biscutum spp. and Similiscutum spp.) and of Schizosphaerella spp., while distal assemblages are dominated by Crepidolithus crassus and Schizospharella spp. Crepidolithus crassus is interpreted as a deep-dweller coccolithophorid, inhabiting preferentially distal and deeper settings in the Lusitanian Basin. Placolith-bearing coccolithophorids were more abundant in proximal settings with respect to emerged lands, under relatively elevated trophic conditions. The probable calcareous dinocyst Schizospharella spp. proliferated in surface waters of both proximal and distal environments.
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late pliensbachian early toarcian early jurassic environmental changes in an epicontinental basin of nw europe causses area central france a micropaleontological and geochemical approach
Palaeogeography Palaeoclimatology Palaeoecology, 2009Co-Authors: Samuel Mailliot, Annachiara Bartolini, Emanuela Mattioli, Bernard Pittet, Francois Baudin, Jean GuexAbstract:Abstract We present an integrated work based on calcareous nannofossil and benthic foraminiferal assemblages, and geochemical analyses of two Upper Pliensbachian–Lower Toarcian sections located in the central-South France. The studied sections, Tournadous and Saint-Paul-des-Fonts, represent the proximal and the distal part, respectively, of the Jurassic Causses Basin, one of the small, partly enclosed basins belonging to the epicontinental shelf of the NW Tethys. At the transition from Late Pliensbachian to Early Toarcian, the Causses Basin recorded an emersion in response to the global sea-level fall. Our data indicate severe environmental conditions of marine waters, including salinity decrease and anoxia development, occurring in the Early Toarcian. The acme of this deterioration coincides with the Early Toarcian Anoxic Event (T-OAE) but, due to the restricted nature of the basin, anoxia persisted until the end of the Early Toarcian, mainly in the deeper parts of the basin. The micronutrients and organic organic-matter fluxes were probably high during the entire studied time interval, as shown by nannofossil and foraminiferal assemblages. However, nannoplankton production drastically decreased during the T-OAE, as demonstrated by very low nannofossil fluxes, and only taxa tolerant to low-saline surface waters could thrive. At the same time, benthic foraminifers temporarily disappeared in response to sea-bottom anoxia. Our study demonstrates that environmental changes related to the T-OAE are well-recorded even in small, partly enclosed basins of NW Europe, like the Causses Basin. Within this area, the effects of global changes, like sea sea-level and temperature fluctuations, are modulated by local conditions mainly controlled by the morphology of the basin.
Michael Wagreich - One of the best experts on this subject based on the ideXlab platform.
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paleocene eocene calcareous nannofossil biostratigraphy and cyclostratigraphy from the neo tethys pabdeh formation of the zagros basin iran
2018Co-Authors: Seyed Hamidreza Azami, Michael Wagreich, Erik Wolfgring, Mohamad Hosein Mahmudy GharaieAbstract:Abstract The Pabdeh Formation in the Zagros Basin, Iran, records cyclic pelagic sedimentation from the middle Paleocene to the middle Eocene in a Tethyan setting. The cyclic successions consist of deeper-water pelagic to hemipelagic shale, marl (stone) and limestone, with a predominantly shaly lower part, and a marl-limestone upper part. Nannofossil biostratigraphy indicates standard zones CNP8 - NP6 to CNE8 - NP14. The Paleocene-Eocene Thermal Maximum (PETM) interval is indicated by a distinct nannofossil assemblages and a significant negative carbon isotope excursion. Sediment accumulation rates are in general around 6–68 mm/ka. Cyclic signals investigated include fluctuations in carbonate content. Power spectra using LOWSPEC (Robust Locally-Weighted Regression Spectral Background Estimation) and EHA (Evolutive Harmonic Analysis) indicate the presence of twentyone 405 ka cycles from the base of the PETM up to the top of the studied section. Orbital tuning to the established Laskar target curve is in accordance with the general Paleocene-Eocene cyclostratigraphy and yields insights into Paleogene chronostratigraphy.
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tethyan plankton bioevents calibrated to stable isotopes across the upper santonian lower campanian transition in north western tunisia
Cretaceous Research, 2017Co-Authors: Sherif Farouk, Mahmoud Faris, Zaineb Elamri, Fayez Ahmad, Michael WagreichAbstract:Abstract Calcareous nannofossil and planktonic foraminifera biostratigraphic datums are correlated with carbon isotope stratigraphy across the upper Santonian–lower Campanian transition from Ain Zouakra outcrop (Elles area) in north-western Tunisia. Twenty two calcareous microplankton bio-events are identified and discussed, including 11 planktonic foraminiferal and 11 nannofossil events. The studied upper Santonian–lower Campanian succession can be divided into five nannofossil zones (CC17/UC13 to CC21/UC15c) equivalent to three planktonic foraminiferal zones named Dicarinella asymetrica, Globotruncanita elevata , Globotruncana ventricosa . The Santonian/Campanian Boundary Event (SCBE) is characterized by a positive δ 13 C double peaks. The first peak (a) occurs within the uppermost CC17 Zone and Dicarinella asymetrica Zone. The second peak (b) directly occurs below the base of CC18 (FO of Bronsonia parca parca ) and last occurrence (LO) of Dicarinella asymetrica . It is marked by several extinction bioevents of representatives of Whiteinella , Dicarinella and Sigalia and the gradual disappearance of species of Marginotruncana (all species except M. sinuosa and M. marginata ). At the beginning of the Campanian a diversification of Globotruncanidae was noted.
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nannofossil biostratigraphy strontium and carbon isotope stratigraphy cyclostratigraphy and an astronomically calibrated duration of the late campanian radotruncana calcarata zone
Cretaceous Research, 2012Co-Authors: Michael Wagreich, Johann Hohenegger, Stephanie NeuhuberAbstract:A section from the southern (Austro-Alpine Northern Calcareous Alps) margin of the Penninic Ocean in the NW Tethys realm of Late Campanian age is investigated stratigraphically. Plankton foraminifer and nannofossil biostratigraphy designate the presence of the Globotruncana ventricosa Zone and the Radotruncana (Globotruncanita) calcarata Zone, and standard nannofossil zones CC21–UC15cTP and CC22ab–UC15deTP. The combination of carbon isotope stratigraphy, strontium isotopes, and cyclostratigraphy allows a detailed chronostratigraphic correlation. Periodicity was obtained by power spectral analysis, sinusoidal regression, and Morlet wavelets. The duration of the calcarata Total Range Zone is calculated by orbital cyclicity expressed in thickness data of limestone–marl rhythmites and stable carbon isotope data. Precessional, obliquity, and short and long eccentricity cycles are identified and give an extent of c. 806 kyr for the zone. Mean sediment accumulation rates are as low as 1.99 cm/kyr and correspond well to sediment accumulation rates in similar settings. We further discuss chronostratigraphic implications of our data.
