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Jacques Verniers - One of the best experts on this subject based on the ideXlab platform.
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Chitinozoan Biozonation and new lithostratigraphical data in the Upper Ordovician of the Fauquez and Asquempont areas (Brabant Massif, Belgium)
Geologica Belgica, 2005Co-Authors: Jan Vanmeirhaeghe, Annelies Storme, Koen Van Noten, Geert Van Grootel, Jacques VerniersAbstract:A chitinozoan Biozonation is established for the Upper Ordovician rocks of the Sennette valley in the Fauquez area and the Asquempont area, revising the existing chitinozoan Biozonation of the Brabant Massif. The chitinozoans of fi ve formations (the Ittre, Bornival, Huet, Fauquez and Madot formations) are studied from 70 samples. The chitinozoan Biozonation is correlated with Baltoscandia and the Avalonian Upper Ordovician type sections in the U.K. This correlation provides an accurate dating of the studied formations. A megaslumping event, affecting a part of the Ittre and Bornival Formation and causing the overturning of a pile of sediments estimated at minimum 200 m thick, may be placed in the mid Oandu (Cheneyan, middle Caradoc, early "Stage 6"). The volcanic rocks in the Fauquez area, formally thought to be restricted to the Ashgill, are confi ned to the late Caradoc - early Ashgill timespan. In addition to this, this paper presents new lithostratigraphical data on the Ittre Formation and the lower member of the Bornival Formation.
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Chitinozoan bio- and lithostratigraphical study of the Ashgill Fosses and Génicot Formations (Condroz Inlier, Belgium)
Review of Palaeobotany and Palynology, 2004Co-Authors: Jan Vanmeirhaeghe, Jacques VerniersAbstract:Abstract Ashgill chitinozoans from the Fosses and the Genicot Formations were studied in seven sections in the western part of the Condroz Inlier, Belgium. Twenty-three previously published samples as well as thirty-five new samples were analysed. The combination of the results led to the definition of six local biozones and a local Biozonation for the Ashgill of the region west of Fosses and eventually to the dating of both formations studied. Generally, the local Biozonation allowed correlation of the sections. In combination with the detailed study of the lithostratigraphy, a hypothesis is proposed concerning the depositional history of both formations. Two conglomeratic levels in the Genicot Formation might be the sedimentological response to the sea level drop associated with the Hirnantian glaciation event. Two new species are defined: Spinachitina fossensis and Conochitina eustachensis .
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A chitinozoan biostratigraphy of the Upper Ordovician and lower Silurian strata of the Girvan area, Midland Valley, Scotland
Transactions of the Royal Society of Edinburgh: Earth Sciences, 2002Co-Authors: Thijs Vandenbroucke, Jacques Verniers, Euan N.k. ClarksonAbstract:ABSTRACTForty-six samples, taken from the Upper Ordovician and lower Silurian strata of the Girvan district, Midland Valley of Scotland, yield moderately well-preserved and diverse assemblages of chitinozoans. The area was chosen to study the composition of the chitinozoan assemblages, rarely described before in Scotland, which lay at the south-eastern margin of the Laurentia palaeocontinent. These assemblages are compared with those of the same age on other palaeocontinents, representing a critical time when both the Iapetus and Tornquist oceans were closing, thus forming the Caledonide and associated orogens. It is possible to correlate the chitinozoan occurrences at Girvan with those of other parts of Laurentia (Quebec area), other palaeocontinents such as Baltoscandia (Sweden, Estonia), Avalonia (Wales, Brabant Massif) and some parts of Northern Gondwana (Saudi Arabia). For the lower Silurian, it is possible to correlate with the global chitinozoan Biozonation, and a calibration between the chitinozoan occurrences and the graptolite Biozonation of Girvan is established. Several levels within the Balclatchie, South Shore, Three Mile, Shalloch, Wood Burn, Lauchlan, Drumyork Flags and other formations are accurately dated.
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Ordovician chitinozoan Biozonation of the Brabant Massif, Belgium
Review of Palaeobotany and Palynology, 2000Co-Authors: Joakim Samuelsson, Jacques VerniersAbstract:Abstract Chitinozoans from seven Ordovician units (Abbaye de Villers, Tribotte, Rigenee, Ittre, Bornival, and Brutia formations and a new unnamed unit, here provisionally called the Asquempont unit) belonging to the mainly concealed Brabant Massif, Belgium are described herein. Fifty-six samples were taken from rocks cropping out at the south-eastern rim of the massif in the Orneau, Dyle–Thyle and Senne–Sennette valleys. Microfossil preservation is moderate to poor, and the chitinozoans occur in low numbers. Taxonomically, the recovered chitinozoans are distributed into 29 taxa, some placed under open nomenclature. Together with earlier published graptolite and acritarch data, the analysis of the chitinozoan assemblages resulted in an improved chronostratigraphy of the investigated formations. We propose a local chitinozoan Biozonation with 11 zones for the Brabant Massif. The oldest investigated units yielded chitinozoans typical for North Gondwana, and younger units (starting in the middle Caradoc), yielded some taxa also common in Baltica. As the Brabant Massif formed part of the microcontinent Avalonia, the chitinozoan assemblages recovered from the massif support the inferred drifting of Avalonia from high latitudes towards middle latitudes in the Ordovician as was suggested earlier.
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Middle to Late Ordovician Chitinozoan Biozonation of the Sennette, Dyle-Thyle and Orneau Valleys, Brabant Massif, Belgium
1999Co-Authors: Joakim Samuelsson, Jacques VerniersAbstract:Middle to Late Ordovician Chitinozoan Biozonation of the Sennette, Dyle-Thyle and Orneau Valleys, Brabant Massif, Belgium
Carles Martinclosas - One of the best experts on this subject based on the ideXlab platform.
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maastrichtian basal paleocene charophyte Biozonation and its calibration to the global polarity time scale in the southern pyrenees catalonia spain
Cretaceous Research, 2015Co-Authors: Alba Vicente, Carles MartinclosasAbstract:Abstract A new charophyte Biozonation for the non-marine Maastrichtian−lowermost Paleocene deposits in the South-Eastern Pyrenean Vallcebre Basin is proposed and calibrated to the Global Polarity Time Scale (GPTS) using magnetostratigraphic data. Planktonic foraminifera associated with charophyte assemblages provide maximum ages for correlation between non-marine and marine biostratigraphic zonations. The new charophyte Biozonation is intended to be useful for terrigenous floodplain facies (red beds) with poorly developed lacustrine intervals and strong palaeoecological constraints for the development of charophytes. The taxonomy of charophytes was revisited and two new species were defined, Microchara nana Vicente and Martin-Closas and Peckichara serrata Vicente and Martin-Closas. Sedimentological analyses carried out in parallel with taphonomic observations allow us to infer the palaeoecological constraints of charophyte species. The new Biozonation encompasses three biozones for the late Campanian−early Paleocene interval. The partial range biozone of Peckichara cancellata starts in chron C32r (∼73.91 Ma) according to previous studies, and extends its upper limit to chron C31r, with an age of ∼69.90 Ma in the Vallcebre Basin. The new Microchara punctata local biozone includes biozones of Septorella ultima (upper part), Microchara cristata and Peckichara sp. 1 (lower part) previously defined by Feist in Riveline et al. (1996). Some of these biozones were poorly characterized or were based on species with strong palaeoecological constraints. The lower Danian is characterized by the biozone of Peckichara toscarensis, replacing the previous biozone of Peckichara llobregatensis. The latter species was found to occur in the Maastrichtian.
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charophytes from the barremian lower aptian of the northern subalpine chains and jura mountains france correlation with associated marine assemblages
Cretaceous Research, 2009Co-Authors: Carles Martinclosas, Bernard Clavel, Jean Charollais, Rolf Schroeder, Marc André ConradAbstract:Abstract Interdigitation of shallow marine limestone containing orbitolinids (benthic foraminifera), echinoids and dasycladales with lacustrine limestone and marl with charophytes in the Northern Subalpine Chains and Jura Mountains, France, enables us to improve the correlation between Early Cretaceous continental and marine Biozonations. Early Barremian charophytes were found in marlstones intercalated in the Urgonian Limestone at Pas du Frou (Chartreuse Massif). This flora belongs to the Triquetra charophyte biozone (European Charophyte Biozonation) and is interlayered with rocks containing a characteristic assemblage of orbitolinids and dasycladales of the mid- to early Barremian (uppermost Hugii, Nicklesii and lowermost Caillaudianus ammonite biozones). Younger charophyte associations occur in the overlying Urgonian Limestone and Lower Orbitolina Beds above the major regional unconformity Δ 1 from the Chartreuse Massif, Vercors Massif and Southern Jura Mountains. They are formed by a charophyte association that belongs to the charophyte biozone Cruciata. The flora is interlayered with marine layers rich in orbitolinids and echinoids which enables us to redefine the Cruciata biozone as Cruciata-Paucibracteatus zone, ranging from the late Barremian (Vandenheckii ammonite biozone) to the early Aptian (ammonite biozone Weisii). An interval of uncertainty occurs in the beginning of the Cruciata biozone, which is equivalent to the upper part of the Caillaudianus ammonite biozone.
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new correlation between charophyte and larger foraminifera biozones middle eocene southeastern pyrenees
Geobios, 1999Co-Authors: Carles Martinclosas, Pere Busquets, Josep Serrakiel, Emilio RamosguerreroAbstract:A correlation between the charophyte index-species Raskyella peckii and the Biozonation of larger foraminifera (Shallow Benthic Zones SBZ 13 and SBZ 18) is proposed, which results in a widening to about 6 MA of the present known chronostratigraphic range of the charophyte species. The new range is Early Lutetian to Late Bartonian. This leads to a significant modification in charophyte Biozonation including a redefinition of the charophyte biozone of Raskyella peckii as a partial range zone and the elimination of the biozone of Maedleriella embergeri (Early Lutetian). In addition, the new chronostratigraphic range of Raskyella peckii overlaps the range of the related species Raskyella vadaszi, covering the gap which separated both species. Gaps in the fossil record of Raskyellaceae gave rise to the hypothesis of a polyphyletic origin for this fossil family. The new, continuous chronostratigraphic range suggests that at least the genus Raskyella appears to be monophyletic and did not originate from different characean ancestors.
Alba Vicente - One of the best experts on this subject based on the ideXlab platform.
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maastrichtian basal paleocene charophyte Biozonation and its calibration to the global polarity time scale in the southern pyrenees catalonia spain
Cretaceous Research, 2015Co-Authors: Alba Vicente, Carles MartinclosasAbstract:Abstract A new charophyte Biozonation for the non-marine Maastrichtian−lowermost Paleocene deposits in the South-Eastern Pyrenean Vallcebre Basin is proposed and calibrated to the Global Polarity Time Scale (GPTS) using magnetostratigraphic data. Planktonic foraminifera associated with charophyte assemblages provide maximum ages for correlation between non-marine and marine biostratigraphic zonations. The new charophyte Biozonation is intended to be useful for terrigenous floodplain facies (red beds) with poorly developed lacustrine intervals and strong palaeoecological constraints for the development of charophytes. The taxonomy of charophytes was revisited and two new species were defined, Microchara nana Vicente and Martin-Closas and Peckichara serrata Vicente and Martin-Closas. Sedimentological analyses carried out in parallel with taphonomic observations allow us to infer the palaeoecological constraints of charophyte species. The new Biozonation encompasses three biozones for the late Campanian−early Paleocene interval. The partial range biozone of Peckichara cancellata starts in chron C32r (∼73.91 Ma) according to previous studies, and extends its upper limit to chron C31r, with an age of ∼69.90 Ma in the Vallcebre Basin. The new Microchara punctata local biozone includes biozones of Septorella ultima (upper part), Microchara cristata and Peckichara sp. 1 (lower part) previously defined by Feist in Riveline et al. (1996). Some of these biozones were poorly characterized or were based on species with strong palaeoecological constraints. The lower Danian is characterized by the biozone of Peckichara toscarensis, replacing the previous biozone of Peckichara llobregatensis. The latter species was found to occur in the Maastrichtian.
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Maastrichtian−basal Paleocene charophyte Biozonation and its calibration to the Global Polarity Time Scale in the southern Pyrenees (Catalonia, Spain)
Cretaceous Research, 2015Co-Authors: Alba Vicente, Carles Martín-closas, José Antonio Arz, Oriol OmsAbstract:Abstract A new charophyte Biozonation for the non-marine Maastrichtian−lowermost Paleocene deposits in the South-Eastern Pyrenean Vallcebre Basin is proposed and calibrated to the Global Polarity Time Scale (GPTS) using magnetostratigraphic data. Planktonic foraminifera associated with charophyte assemblages provide maximum ages for correlation between non-marine and marine biostratigraphic zonations. The new charophyte Biozonation is intended to be useful for terrigenous floodplain facies (red beds) with poorly developed lacustrine intervals and strong palaeoecological constraints for the development of charophytes. The taxonomy of charophytes was revisited and two new species were defined, Microchara nana Vicente and Martin-Closas and Peckichara serrata Vicente and Martin-Closas. Sedimentological analyses carried out in parallel with taphonomic observations allow us to infer the palaeoecological constraints of charophyte species. The new Biozonation encompasses three biozones for the late Campanian−early Paleocene interval. The partial range biozone of Peckichara cancellata starts in chron C32r (∼73.91 Ma) according to previous studies, and extends its upper limit to chron C31r, with an age of ∼69.90 Ma in the Vallcebre Basin. The new Microchara punctata local biozone includes biozones of Septorella ultima (upper part), Microchara cristata and Peckichara sp. 1 (lower part) previously defined by Feist in Riveline et al. (1996). Some of these biozones were poorly characterized or were based on species with strong palaeoecological constraints. The lower Danian is characterized by the biozone of Peckichara toscarensis, replacing the previous biozone of Peckichara llobregatensis. The latter species was found to occur in the Maastrichtian.
Jindřich Hladil - One of the best experts on this subject based on the ideXlab platform.
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early devonian lochkovian early emsian bioevents and conodont response in the prague synform czech republic
Palaeogeography Palaeoclimatology Palaeoecology, 2020Co-Authors: Ladislav Slavik, Jindřich HladilAbstract:Abstract The Devonian succession of the Prague Synform is characterized by two major lithofacies: shallow-water biodetrital, mostly crinoidal limestones that also include a reefal skeletal accumulation of Pragian age, and a more pelagic facies that is represented mostly by calcisiltites. Among the several Devonian prominent sea-level fluctuations, some can be traced globally, e.g., the Basal Pragian and Kacak events. In recent years, conodont biostratigraphy of the Early Devonian (Lochkovian, Pragian and early Emsian) of the Prague Synform has been refined. The regional subdivision of the Lower Devonian in its type area has been greatly improved by the integration of new biostratigraphic, chemostratigraphic, sedimentological, and petrophysical data that has, in turn, strengthened global correlations for this interval in Earth's history. The complete conodont Biozonation of the Early Devonian interval (basal Lochkovian – earliest Emsian) in the Prague Synform includes 17 biozones, which can be applied to sections representing various depositional environments and have more global applicability than previously proposed ‘global’ conodont Biozonations. The zonal scale enables a precise biostratigraphic delimitation of the major Early Devonian biotic events (Silurian-Devonian Boundary Event, Lochkovian-Pragian Event and Basal Zlichovian Event). There were major changes in the conodont fauna in response to the Silurian-Devonian Boundary and Lochkovian-Pragian events, however the Basal Zlichovian Event was only characterized by a very gradual transition in the conodont fauna. In parallel to the traditional events defined for the Prague Synform, seven other significant conodont events have been documented. These events represent major turnovers in the conodont fauna that have a direct impact on conodont biostratigraphy, specifically at a global scale. The Icriodus and Irregularis events are congruent with the lower boundaries of the Lochkovian and Pragian stages, respectively. The conodont events established in the Prague Synform largely reflect variations in the seawater depth but are generally independent of lithological changes within sections of the Prague Synform.
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Early Devonian (Lochkovian – early Emsian) bioevents and conodont response in the Prague Synform (Czech Republic)
Palaeogeography Palaeoclimatology Palaeoecology, 2020Co-Authors: Ladislav Slavik, Jindřich HladilAbstract:Abstract The Devonian succession of the Prague Synform is characterized by two major lithofacies: shallow-water biodetrital, mostly crinoidal limestones that also include a reefal skeletal accumulation of Pragian age, and a more pelagic facies that is represented mostly by calcisiltites. Among the several Devonian prominent sea-level fluctuations, some can be traced globally, e.g., the Basal Pragian and Kacak events. In recent years, conodont biostratigraphy of the Early Devonian (Lochkovian, Pragian and early Emsian) of the Prague Synform has been refined. The regional subdivision of the Lower Devonian in its type area has been greatly improved by the integration of new biostratigraphic, chemostratigraphic, sedimentological, and petrophysical data that has, in turn, strengthened global correlations for this interval in Earth's history. The complete conodont Biozonation of the Early Devonian interval (basal Lochkovian – earliest Emsian) in the Prague Synform includes 17 biozones, which can be applied to sections representing various depositional environments and have more global applicability than previously proposed ‘global’ conodont Biozonations. The zonal scale enables a precise biostratigraphic delimitation of the major Early Devonian biotic events (Silurian-Devonian Boundary Event, Lochkovian-Pragian Event and Basal Zlichovian Event). There were major changes in the conodont fauna in response to the Silurian-Devonian Boundary and Lochkovian-Pragian events, however the Basal Zlichovian Event was only characterized by a very gradual transition in the conodont fauna. In parallel to the traditional events defined for the Prague Synform, seven other significant conodont events have been documented. These events represent major turnovers in the conodont fauna that have a direct impact on conodont biostratigraphy, specifically at a global scale. The Icriodus and Irregularis events are congruent with the lower boundaries of the Lochkovian and Pragian stages, respectively. The conodont events established in the Prague Synform largely reflect variations in the seawater depth but are generally independent of lithological changes within sections of the Prague Synform.
Yngve Grahn - One of the best experts on this subject based on the ideXlab platform.
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Ordovician and Silurian chitinozoan biozones of western Gondwana
Geological Magazine, 2006Co-Authors: Yngve GrahnAbstract:A formal Ordovician–Silurian chitinozoan Biozonation for western Gondwana is proposed. This palaeogeographic province includes South America, and was located in medium to high latitudes during Ordovician and Silurian times. Ordovician chitinozoans are known from northern Argentina, southern Bolivia, and Brazil. Silurian chitinozoans occur in Brazil, northern Argentina, southern Bolivia and southern Peru. No published information is available about Ordovician–Silurian chitinozoans from Ecuador, Colombia or Venezuela. Altogether more than 150 localities (including wells and outcrops) are included in this study, and 154 species have been encountered. A Biozonation based on the first occurrence of critical chitinozoan species is introduced. Five biozones are defined in the Ordovician (zones of Desmochitina sp. gr. minor , Conochitina decipiens , Eremochitina brevis , Lagenochitina obeligis and Tanuchitina anticostiensis ), and nine in the Silurian (zones of Belonechitina postrobusta , Spinachitina harringtoni , Pogonochitina djalmai , Margachitina margaritana–Salopochitina monterrosae , Angochitina echinata , Eisenackitina granulata , Fungochitina kosovensis and the subzones of Sphaerochitina solutidina and Desmochitina cf. D. densa ). These biozones are compared with known graptolite, conodont, acritarch and spore zones from the same area, and chitinozoan zones on a global basis.
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Devonian chitinozoan biozones of Western Gondwana
Acta Geologica Polonica, 2005Co-Authors: Yngve GrahnAbstract:A formal Devonian chitinozoan Biozonation for western Gondwana is proposed. This palaeogeographic province corresponds to South America, and was located in medium to high latitudes during the Devonian. Devonian chitinozoans are known from northern Argentina, Bolivia, Brazil and eastern Paraguay. Altogether 230 localities (including wells and outcrops) are included in this study, and 171 species have been encountered. One new species, Angochitina praedensibaculata , is described. A Biozonation based on the first occurrence of critical chitinozoan species is introduced. Thirteen biozones are defined: the Angochitina praedensibaculata , Angochitina strigosa , Urochitina loboi , Ramochitina magnifica , Ancyrochitina pachycerata, Ancyrochitina parisi , Alpenachitina eisenacki , Ramocllitina stiphrospinata , Fungochitina microspinosa - Ancyrochitina taouratinensis , Hoegisphaera glabra , Urochitina bastosi - Sommeroci1itina langei , Fungochitina fenestrata and Fungochitina ultima zones. These biozones are compared with known spore zones from the same area, and chitinozoan biozones on a global basis.
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Lower Silurian (Llandovery-Middle Wenlock) Chitinozoa and biostratigraphy of the mainland of Sweden
GFF, 1998Co-Authors: Yngve GrahnAbstract:Abstract Lower Silurian (Llandovery-Middle Wenlock) chitinozoans from the mainland of Sweden have been investigated from the provinces of Skane, Vastergotland, Ostergotland and Dalarna. Altogether twenty-three species from twelve genera, of which one species, Euconochitina praeclaviformis, is described as new, and four species left in open nomenclature are commented upon. A chitinozoan Biozonation, with eight zones and subzones, for the lower Silurian of Sweden is proposed and compared with the graptolite zones.