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Stanislas Loboziak - One of the best experts on this subject based on the ideXlab platform.
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INTEGRATED MIDDLE AND LATE DEVONIAN Miospore AND CHITINOZOAN
2015Co-Authors: José Henrique, G. De Melo, Stanislas LoboziakAbstract:ABSTRACT – New, hitherto unpublished Miospore information from the Middle and Upper Devonian of the Parnaíba Basin, northeastern and north-central Brazil, has enabled refinement of the chitinozoan zonation recently proposed for that basin. To a large extent, Devonian Miospore zones defined for the Amazonas Basin can be also recognized in the Parnaíba Basin and other Western Gondwanan basins. The Miospore zones are discussed and compared to the coeval Southern Euramerican Miospore zonation, the regional Petrobras palynozones, and to the chitinozoan zonation of the Parnaíba Basin, additional Western Gondwanan regions, and other parts of the world. Key words: Chitinozoans, Miospores, Middle/Late Devonian, Parnaíba Basin, Brazil. RESUMO – Informações novas e até então inéditas acerca dos miósporos do Devoniano Médio e Superior da bacia do Parnaíba, no nordeste e centro-norte brasileiros, permitiram refinar o zoneamento de quitinozoários devonianos proposto recentemente para aquela bacia. Muitas das biozonas de miósporos erigidas no Devoniano da bacia do Amazonas podem ser também aplicadas à bacia do Parnaíba e outras bacias do Gondwana Ocidental. Essas biozonas são discutidas e comparadas com o zoneamento coetâneo de miósporos da Euramérica meridional, com as palinozonas regionais da Petrobras, e com os zoneamentos de quitinozoários da bacia do Parnaíba, de demais regiões do Gondwana Ocidental, e de outras partes do mundo. Palavras-chave: Quitinozoários, miósporos, Devoniano Médio/Superior, bacia do Parnaíba, Brasil
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Integrated Middle and Late Davonian Miospore and chitinozoan zonation of the Parnaiba Basin, Brazil: an update
Rev. bras. Paleontol., 2006Co-Authors: Yngve Grahn, José Henrique G. Melo, Stanislas LoboziakAbstract:New, hitherto unpublished Miospore information from the Middle and Upper Devonian of the Parnaiba Basin, northeastern and northcentral Brazil, has enabled refinement of the chitinozoan zonation recently proposed for that basin. To a large extent, Devonian Miospore zones defined for the Amazonas Basin can be also recognized in the Parnaiba Basin and other Western Gondwanan basins. The Miospore zones are discussed and compared to the coeval Southern Euramerican Miospore zonation, the regional Petrobras palynozones, and to the chitinozoan zonation of the Parnaiba Basin, additional Western Gondwanan regions, and other parts of the world.
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devonian early carboniferous Miospore biostratigraphy of the amazon basin northern brazil
Review of Palaeobotany and Palynology, 2003Co-Authors: José Henrique G. Melo, Stanislas LoboziakAbstract:Abstract A Miospore biozonation, including 17 new interval zones, is proposed for Devonian–Early Carboniferous stratigraphic sections in the Amazon Basin. It results from a detailed review of the coeval Miospore assemblages and biohorizons in the basin. The combined use of selected Euramerican and Western Gondwanan forms as zonal and characteristic taxa permits accurate subdivision, dating and correlation of Amazon Basin palyniferous strata in terms of equivalent Miospore zones of Western Europe and the Old Red Sandstone Continent. The Miospore data provide new insights into such varied issues as e.g. the age and stratigraphic relationships of regional rock units, the detection and dating of intervening hiatuses, condensed sedimentary sections, anoxic phases, and resedimentation cycles. Although primarily devised to serve as a regional biozonation, the scheme presented here has a unifying character because it can be applied to other Paleozoic basins in Brazil and Western Gondwanan regions where similar Miospore successions are documented. A Miospore assemblage zone recently described for the early Late Carboniferous interval of the Amazon Basin is also partly reviewed and integrated with the new biozonation for the older sections.
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Devonian–Early Carboniferous Miospore biostratigraphy of the Amazon Basin, Northern Brazil
Review of Palaeobotany and Palynology, 2003Co-Authors: José Henrique G. Melo, Stanislas LoboziakAbstract:Abstract A Miospore biozonation, including 17 new interval zones, is proposed for Devonian–Early Carboniferous stratigraphic sections in the Amazon Basin. It results from a detailed review of the coeval Miospore assemblages and biohorizons in the basin. The combined use of selected Euramerican and Western Gondwanan forms as zonal and characteristic taxa permits accurate subdivision, dating and correlation of Amazon Basin palyniferous strata in terms of equivalent Miospore zones of Western Europe and the Old Red Sandstone Continent. The Miospore data provide new insights into such varied issues as e.g. the age and stratigraphic relationships of regional rock units, the detection and dating of intervening hiatuses, condensed sedimentary sections, anoxic phases, and resedimentation cycles. Although primarily devised to serve as a regional biozonation, the scheme presented here has a unifying character because it can be applied to other Paleozoic basins in Brazil and Western Gondwanan regions where similar Miospore successions are documented. A Miospore assemblage zone recently described for the early Late Carboniferous interval of the Amazon Basin is also partly reviewed and integrated with the new biozonation for the older sections.
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devonian Miospore successions of western gondwana update and correlation with southern euramerican Miospore zones
Review of Palaeobotany and Palynology, 2002Co-Authors: Stanislas Loboziak, José Henrique G. MeloAbstract:Abstract The composition and main biohorizons of Devonian Miospore successions of Western Gondwanan regions are reviewed and compared to corresponding Miospore zones of Southern Euramerica. The stratigraphic distribution of the most significant taxa is recorded in the main investigated basins of North Africa, Saudi Arabia and Brazil. With the exception of certain forms geographically restricted to Western Gondwana, most of the stratigraphically useful taxa are common to both Southern Euramerica and Western Gondwana. Successions of Western European-defined zones can be recognized and correlated in Western Gondwana regions on the basis of these common index species. Many Devonian Miospore biozones defined in Western Europe are well represented in Western Gondwana, whereas some remain unrecorded or poorly characterized. The biozones may alternate with intervals with poor biostratigraphic resolution which can be attributed to various causative agents.
José Henrique G. Melo - One of the best experts on this subject based on the ideXlab platform.
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siluro devonian Miospore biostratigraphy of the urubu river area western amazon basin northern brazil
Geobios, 2008Co-Authors: Philippe Steemans, Claudia V. Rubinstein, José Henrique G. MeloAbstract:Abstract Well-preserved Miospores have been observed in the Urubu River area from the western part of the Amazon Basin, northern Brazil, in rocks belonging to the uppermost Pitinga and Manacapuru Formations. A previous palynological work based on chitinozoans has dated these strata as Late Ludlow, Early Pridoli and Early Lochkovian. Although samples are relatively poor in Miospores, the present study reveals the most diversified Silurian–Earliest Lochkovian palynoflora ever reported from South America, an interval where Miospore information is still very rare. Sixty-four species have been identified, of which two are new ( Artemopyra urubuense and Retusotriletes amazonensis ). One single specimen attributed to the genus Grandispora , identical to unpublished forms identified by one of us (P.S.) in Lochkovian sections of Saudi Arabia, has been found in a Lochkovian sample from the Urubu River. These constitute the oldest geological record of Grandispora . Among the abundant acritarchs, specimens of the genus Schizocystia have been observed for the first time in pre-Devonian rocks. Although the Late Silurian–Early Lochkovian Miospore biostratigraphy is still in its infancy in South America, it seems that Amazon Basin assemblages do not show significant differences in composition in comparison to coeval palynofloras from other areas of northwestern Gondwana. This is surprising since the Miospore localities under consideration are widely distributed over high to low paleolatitudes, i.e. from cool temperate to dry subtropical belts. Conversely, Siluro-Devonian Gondwanan assemblages differ considerably from the contemporary palynofloras of the Old Red Sandstone Continent and adjacent areas, thus contradicting recent phytogeographic interpretations based on megafloras.
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Integrated Middle and Late Davonian Miospore and chitinozoan zonation of the Parnaiba Basin, Brazil: an update
Rev. bras. Paleontol., 2006Co-Authors: Yngve Grahn, José Henrique G. Melo, Stanislas LoboziakAbstract:New, hitherto unpublished Miospore information from the Middle and Upper Devonian of the Parnaiba Basin, northeastern and northcentral Brazil, has enabled refinement of the chitinozoan zonation recently proposed for that basin. To a large extent, Devonian Miospore zones defined for the Amazonas Basin can be also recognized in the Parnaiba Basin and other Western Gondwanan basins. The Miospore zones are discussed and compared to the coeval Southern Euramerican Miospore zonation, the regional Petrobras palynozones, and to the chitinozoan zonation of the Parnaiba Basin, additional Western Gondwanan regions, and other parts of the world.
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devonian early carboniferous Miospore biostratigraphy of the amazon basin northern brazil
Review of Palaeobotany and Palynology, 2003Co-Authors: José Henrique G. Melo, Stanislas LoboziakAbstract:Abstract A Miospore biozonation, including 17 new interval zones, is proposed for Devonian–Early Carboniferous stratigraphic sections in the Amazon Basin. It results from a detailed review of the coeval Miospore assemblages and biohorizons in the basin. The combined use of selected Euramerican and Western Gondwanan forms as zonal and characteristic taxa permits accurate subdivision, dating and correlation of Amazon Basin palyniferous strata in terms of equivalent Miospore zones of Western Europe and the Old Red Sandstone Continent. The Miospore data provide new insights into such varied issues as e.g. the age and stratigraphic relationships of regional rock units, the detection and dating of intervening hiatuses, condensed sedimentary sections, anoxic phases, and resedimentation cycles. Although primarily devised to serve as a regional biozonation, the scheme presented here has a unifying character because it can be applied to other Paleozoic basins in Brazil and Western Gondwanan regions where similar Miospore successions are documented. A Miospore assemblage zone recently described for the early Late Carboniferous interval of the Amazon Basin is also partly reviewed and integrated with the new biozonation for the older sections.
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Devonian–Early Carboniferous Miospore biostratigraphy of the Amazon Basin, Northern Brazil
Review of Palaeobotany and Palynology, 2003Co-Authors: José Henrique G. Melo, Stanislas LoboziakAbstract:Abstract A Miospore biozonation, including 17 new interval zones, is proposed for Devonian–Early Carboniferous stratigraphic sections in the Amazon Basin. It results from a detailed review of the coeval Miospore assemblages and biohorizons in the basin. The combined use of selected Euramerican and Western Gondwanan forms as zonal and characteristic taxa permits accurate subdivision, dating and correlation of Amazon Basin palyniferous strata in terms of equivalent Miospore zones of Western Europe and the Old Red Sandstone Continent. The Miospore data provide new insights into such varied issues as e.g. the age and stratigraphic relationships of regional rock units, the detection and dating of intervening hiatuses, condensed sedimentary sections, anoxic phases, and resedimentation cycles. Although primarily devised to serve as a regional biozonation, the scheme presented here has a unifying character because it can be applied to other Paleozoic basins in Brazil and Western Gondwanan regions where similar Miospore successions are documented. A Miospore assemblage zone recently described for the early Late Carboniferous interval of the Amazon Basin is also partly reviewed and integrated with the new biozonation for the older sections.
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devonian Miospore successions of western gondwana update and correlation with southern euramerican Miospore zones
Review of Palaeobotany and Palynology, 2002Co-Authors: Stanislas Loboziak, José Henrique G. MeloAbstract:Abstract The composition and main biohorizons of Devonian Miospore successions of Western Gondwanan regions are reviewed and compared to corresponding Miospore zones of Southern Euramerica. The stratigraphic distribution of the most significant taxa is recorded in the main investigated basins of North Africa, Saudi Arabia and Brazil. With the exception of certain forms geographically restricted to Western Gondwana, most of the stratigraphically useful taxa are common to both Southern Euramerica and Western Gondwana. Successions of Western European-defined zones can be recognized and correlated in Western Gondwana regions on the basis of these common index species. Many Devonian Miospore biozones defined in Western Europe are well represented in Western Gondwana, whereas some remain unrecorded or poorly characterized. The biozones may alternate with intervals with poor biostratigraphic resolution which can be attributed to various causative agents.
Philippe Steemans - One of the best experts on this subject based on the ideXlab platform.
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Upper Silurian Miospores from the Precordillera Basin, Argentina: biostratigraphic, palaeonvironmental and palaeogeographic implications
Geological Magazine, 2013Co-Authors: V.j. Garcia Muro, Claudia V. Rubinstein, Philippe SteemansAbstract:AbstractThis study is concentrated on Ludlow (to Pridoli?) Miospores from the Los Espejos Formation at the Quebrada Ancha locality, Central Precordillera, San Juan Province, Argentina. The Ludlow age is in agreement with the age based on acritarchs. The assemblage of continental palynomorphs is composed of 43 Miospore species (29 trilete spores and 14 cryptospores). A new synonymy is proposed: Chelinospora poecilomorpha is here considered a junior synonym of Clivosispora verrucata. In addition, specimens belonging to C. verrucata var. verrucata and C. verrucata var. convoluta are included in a new morphon. This study represents the second Late Silurian Miospore assemblage described from South America; the first was from the Urubu River, Amazon Basin, northern Brazil. The Quebrada Ancha assemblages allow a reasonably good correlation with biozones established for the Upper Silurian from the Cantabrian Mountains, northern Spain. The dendrogram analysis between coeval Miospore assemblages from different localities shows a strong palaeogeographic affinity with the Miospores recovered from northern Brazil and North Africa. Miospore assemblages from Spain show influences from Baltica and North Africa, demonstrating their intermediate position between these two continental plates. Conversely, dissimilarities recognized between Libya and Tunisia are most probably owing to local ecology and/or environmental conditions.
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Miospores from Ordovician-Silurian Argentinean basins: evolution and relationships with other South American basins
2011Co-Authors: Claudia V. Rubinstein, Victoria J. García Muro, Philippe SteemansAbstract:Miospores from Ordovician-Silurian Argentinean basins: evolution and relationships with other South American basins Claudia V. Rubinstein 1 , Victoria J. Garcia Muro 1 and Philippe Steemans 2 1 Unidad de Paleopalinologia, Departamento de Paleontologia, IANIGLA, CCT- CONICET Mendoza. Av. Ruiz Leal s/n, Parque General San Martin, 5500, Mendoza, Argentina. 2 Paleobotanique, Paleopalynologie, Micropaleontologie (PPM), Department of Geology, University of Liege, B-18, Sart Tilman, 4000 Liege 1, Belgium E-mails: crubinstein@mendoza-conicet.gov.ar , vgarcia@mendoza-conicet.gov.ar , p.steemans@ulg.ac.be . The earliest evidence of land plants are cryptospores ( sensu Steemans 2000) from the Middle Ordovician (Dapingian) of the Sierras Subandinas (NW Argentina). No uncontroversial data are available for the time period ranging from the Darriwilian to the Katian. In the latest Ordovician deposits from the northwestern geological provinces of the Central Andean Basin (Puna, Cordillera Oriental and Sierras Subandinas), there are few cryptospores in the palynological associations from the glacial-related strata (Caspala and Zapla Formations). On the other hand, rich, diverse and well-preserved cryptospore assemblages are observed in the post Hirnantian glaciation levels (Salar del Rincon Formation). Lower Silurian cryptospores are known from the northwestern Argentina Basin and the Precordillera Basin, where they are preserved in marine sediments. The cryptospores are rare and no trilete spores have been observed. The low diversity of Miospores is most probably due to the marine nature of the environment of deposition. Very few palynological data exists from Wenlockian layers. The palynological assemblages are exclusively marine, coming from the Chacoparanense Basin and probably from the northwestern Central Andean Basin. The FAD of trilete spores in Argentina occurs in Ludlovian sediments. The extensive outcrops of the Ludlovian-early Devonian (locally) Los Espejos Formation, in the Precordillera Basin, represent a muddy shelf to inner shelf exposed to storm activity, and storm-dominated shoreface towards the top. They yielded rich and diverse palynomorph assemblages assigned to the Ludlovian. The marine phytoplankton clearly dominates throughout the entire stratigraphic unit, except for the upper productive levels near the Siluro-Devonian boundary in the Rio Jachal locality. Amicosporites cf. miserabilis , A . cf. streelii , Archaezonotriletes chulus Morphon, Chelinospora cf. cassicula , Ch. poecilomorpha , Ch. sanpetrensis , Clivosispora verucata var. verrucata , Retusotriletes cf. amazonensis and Synorisporites verrucatus are among the most relevant trilete spores. Cryptospores such as Artemopyra robusta , A. urubuense and Cymbohilates hystricosus are the most informative taxa. Similarities and differences mainly with Brazilian and Paraguayan assemblages are noticed. The recorded Miospore taxa of the Los Espejos Formation show differences with coeval assemblages, displaying evolutionary innovations that seem to appear firstly in the Precordillera Basin than in other regions. References Steemans, P. (2000). Miospore evolution from the Ordovician to the Silurian. Review of Palaeobotany and Palynology , 113, 189-196.
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siluro devonian Miospore biostratigraphy of the urubu river area western amazon basin northern brazil
Geobios, 2008Co-Authors: Philippe Steemans, Claudia V. Rubinstein, José Henrique G. MeloAbstract:Abstract Well-preserved Miospores have been observed in the Urubu River area from the western part of the Amazon Basin, northern Brazil, in rocks belonging to the uppermost Pitinga and Manacapuru Formations. A previous palynological work based on chitinozoans has dated these strata as Late Ludlow, Early Pridoli and Early Lochkovian. Although samples are relatively poor in Miospores, the present study reveals the most diversified Silurian–Earliest Lochkovian palynoflora ever reported from South America, an interval where Miospore information is still very rare. Sixty-four species have been identified, of which two are new ( Artemopyra urubuense and Retusotriletes amazonensis ). One single specimen attributed to the genus Grandispora , identical to unpublished forms identified by one of us (P.S.) in Lochkovian sections of Saudi Arabia, has been found in a Lochkovian sample from the Urubu River. These constitute the oldest geological record of Grandispora . Among the abundant acritarchs, specimens of the genus Schizocystia have been observed for the first time in pre-Devonian rocks. Although the Late Silurian–Early Lochkovian Miospore biostratigraphy is still in its infancy in South America, it seems that Amazon Basin assemblages do not show significant differences in composition in comparison to coeval palynofloras from other areas of northwestern Gondwana. This is surprising since the Miospore localities under consideration are widely distributed over high to low paleolatitudes, i.e. from cool temperate to dry subtropical belts. Conversely, Siluro-Devonian Gondwanan assemblages differ considerably from the contemporary palynofloras of the Old Red Sandstone Continent and adjacent areas, thus contradicting recent phytogeographic interpretations based on megafloras.
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some considerations on devonian Miospore taxonomy quelques considerations sur la taxonomie des Miospores devoniennes
2007Co-Authors: Pierre Breuer, John Filatoff, Philippe SteemansAbstract:In order to be able to deal with objects human beings need to have name tags for them and to classify them in discrete boxes. It is primarily for this reason that Miospore taxa are named using Linnaean-style Latinized binomial nomenclature, a system formally governed by the International Code of Botanical Nomenclature (ICBN). The purpose of formal nomenclature is to provide a precise, simple and stable system of unique names that can be used by scientists all over the world. This system must allow for expansion and refinement to accommodate increases in knowledge (see T
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the moesian terrane during the lochkovian a new palaeogeographic and phytogeographic hypothesis based on Miospore assemblages
Palaeogeography Palaeoclimatology Palaeoecology, 2004Co-Authors: Philippe Steemans, Iskra LakovaAbstract:Abstract The relative position of terranes during the Palaeozoic can be indicated by a combination of palaeomagnetic and floral/faunal evaluation. Palaeomagnetic data are absent from the Moesian Terrane, South-Eastern Europe, and its position is here estimated thanks to palaeophytogeographic considerations based on Miospore assemblages. Miospore assemblages have been studied in two boreholes from northern Bulgaria. Preliminary analyses of chitinozoans, acritarchs and phytodebris have already been published. The oldest samples were considered to be of Pridoli age based on chitinozoan data, but here we provide new Miospore evidence suggesting a Lochkovian age. This age determination is in accordance with the new interpretations based on previously published acritarch data. It is likely that the previous Pridoli age determination was influenced by Pridoli chitinozoans being reworked into the Lochkovian. The Miospores are typical of assemblages only present in a small area of Avalonia and the western part of the Baltica Plate, and belong to the sinuosus – zavallatus (S–Z) Phytogeographic Province, defined here. On the contrary to the Miospores, marine palynomorphs have affinity with Gondwanan assemblages. The different palaeogeographic affinities of the different palynomorph groups are not necessarily in contradiction, as it has recently been suggested that the Rheic Ocean did not act, around the Silurian–Devonian boundary, as a hermetic barrier for transoceanic chitinozoan and acritarch exchange. Therefore, the results are tentatively interpreted as indicating that the Moesian Terrane, belonging to the S–Z Province, was close to southern Laurussia during the Lower Devonian. This northern position of the Moesian Terrane during the Lower Devonian conflicts with most current palaeogeographic reconstructions, but partially supports the hypothesis of a migration of this terrane from Gondwana to Laurussia during the Palaeozoic. The possible presence of reworked palynomorphs in the Lochkovian may reflect early tectonic events associated with the close proximity of the Moesian Terrane and the Dobrudgea periphery of Palaeo-Europe.
Maurice Streel - One of the best experts on this subject based on the ideXlab platform.
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late frasnian famennian climates based on palynomorph analyses and the question of the late devonian glaciations
Earth-Science Reviews, 2000Co-Authors: Maurice Streel, Stanislas Loboziak, Mario Vicente Caputo, José Henrique G. MeloAbstract:Palynomorph distribution in Euramerica and western Gondwana, from the Latest Givetian to the Latest Famennian, may be explained, to some extent, by climatic changes. Detailed Miospore stratigraphy dates accurately the successive steps of these changes. Interpretation is built on three postulates which are discussed: Euramerica at slightly lower latitudes than generally accepted by most paleomagnetic reconstructions; a conodont time-scale accepted as the most used available subdivision of time; and Late Devonian sea-level fluctuations mainly governed by glacio-eustasy. The Frasnian–Famennian timescale is also evaluated. The comparison, based on conodont correlations, between Givetian and most of the Frasnian Miospore assemblages from, respectively, northern and southern Euramerica demonstrates a high taxonomic diversity in the equatorial belt and much difference between supposed equatorial and (sub) tropical vegetations. On the contrary, a similar vegetation pattern and therefore probably compatible climatic conditions were present from tropical to subpolar areas. A rather hot climate culminated during the Latest Frasnian when equatorial Miospore assemblages reached their maximum width. The Miospore diversity shows also a rather clear global Late Frasnian minimum which is also recorded during the Early and Middle Famennian but only in low latitude regions while, in high latitude, very cold climates without perennial snow may explain the scarcity of Miospores and so, of vegetation. The Early and Middle Famennian conspicuous latitudinal gradient of the vegetation seems to attenuate towards the Late and Latest Famennian but this might be above all the result of the development, of cosmopolitan coastal lowland vegetations (downstream swamps) depending more on the moisture and equable local microclimates than on the probably adverse climates of distant hinterland areas. During that time, periods of cold climate without perennial snow cover and with rare vegetation may have alternated with less cold but wetter climates, thus giving rise to the development of mountain glaciers in high latitudes and explaining the jerking character of the global major marine regression. In high latitude regions, the development of an ice cap reaching sea level is only recorded by the end of the Latest Famennian, immediately below the DCB but, even if glacial evidences are not known at near the FFB, a short (0.1 Ma?) glaciation seems the best reasonable explanation of the major eustatic fall following the Kellwasser Event. The sudden growth and decay of a hypothetical Earliest Famennian ice sheet can be explained by the reduction and, later, increase in greenhouse capacity of the atmosphere. These changes in the atmospheric CO2 might have provoked changes in the mode of ocean-atmosphere operation. It may also be partly controlled by a volcanic paroxysm and/or bolide impacts. The Hony microtektites represent the best known evidence of the impact of extraterrestrial bodies on Earth corresponding to the UKW, and they are immediately followed by a regression, suggested by the quantitative analysis of acritarch assemblages. In the paleo-tropical Late Famennian, a peat-forming vascular plant community occurs for the first time and makes possible quantitative palynology of autochthonous sediments allowing the recognition of different swamp and near-swamp characteristic Miospores. The early Latest Famennian starts with a widespread transgression which could correspond to the melting phases of the hypothetical Late Famennian mountain glaciers. During the end-Famennian, the coastal lowland vegetation has a worldwide distribution from sub-polar to equatorial regions. The climate has become less cold in high latitudes but wetter than before probably because the midlatitude cyclonic activity allows sufficient polar transportation of moisture to form large snow cover. Extensive coastal glaciers developed in different Bolivian and Brazilian basins, well dated by Miospores. Rapid climatic changes characterize the onset of glaciation. The cyclic nature of climate allowed even intertropical marine faunas to reach occasionally the subpolar regions. For the plant kingdom, the crisis which follows the Hangenberg Event was more severe than the Late Frasnian Crisis.
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The Indotriradites dolianitii Morphon, a distinctive group of Miospore species from the Lower Carboniferous of Gondwana
Review of Palaeobotany and Palynology, 1999Co-Authors: Stanislas Loboziak, José Henrique G. Melo, Geoffrey Playford, Maurice StreelAbstract:An emended diagnosis and generic reallocation are proposed for the trilete Miospore Indotriradites dolianitii (Daemon, 1974) Loboziak et al., comb. nov. A new species, I. daemonii Loboziak et al., sp. nov., from Visean strata of Western Gondwana, is erected. These two species, together with I. zosteriformis (Playford et Satterthwait) Playford, 1991 from the Visean of Australia, belong to a cohesive morphological Miospore category, here termed the Indotriradites dolianitii Morphon, which is evidently restricted to the Lower Carboniferous of Gondwana.
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Revision of the late Famennian Miospore zonation scheme in eastern Belgium
Journal of Micropalaeontology, 1999Co-Authors: Nadia Maziane, Kenneth T. Higgs, Maurice StreelAbstract:Abstract. New palynological data have been obtained from the Late Famennian Evieux and Comblain au Pont Formations of the Chanxhe section located in the Ourthe Valley in the eastern part of the Dinant Basin. In the light of this new data the stratigraphic ranges of several zonally important Miospore taxa are now significantly different to those previously recorded. This has necessitated a re-evaluation and revision of the late Famennian Miospore zonation scheme for this region. Apiculiretusispora verrucosa and Vallatisporites hystricosus are now found to occur below the inception of Retispora lepidophyta. Consequently, a new biozone, the Apiculiretusispora verrucosa–Vallatisporites hystricosus VH Biozone is described for the late Fa2c interval. The problematical relationship between the Retispora lepidophyta– Apiculiretusispora verrucosa LV Biozone and the Retispora lepidophyta–Knoxisporites literatus LL Biozone is resolved, and part of the LL Biozone is now considered equivalent to the LV Biozone, which it consequently replaces. The Retispora lepidophyta–Indotriradites explanatus LE Biozone is recorded from the upper part of the Comblain au Pont Formation. A continuous succession of Miospore zones is now established for the late Famennian Fa2c/Fa2d interval which permits more accurate correlations with other regions in Europe and North America. Correlation with the standard conodont biostratigraphy shows that the base of LL Miospore Biozone is correlated with the middle or late expansa Conodont Biozone and the base of LE Miospore Biozone with the early to middle praesulcata Conodont Biozone.
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Late Lower and Middle Devonian Miospores from Saudi Arabia.
Review of Palaeobotany and Palynology, 1995Co-Authors: Stanislas Loboziak, Maurice StreelAbstract:Abstract Late Lower and Middle Devonian Miospores are identified in cuttings from well TRBH-1. A biostratigraphic zonation is proposed and compared with the Miospore zonal scheme defined in Western Europe. All samples contained caved material. By graphic correlation with contemporaneous cored sequences previously analysed in Libya and Tunisia, the first appearance of Geminospora lemurata , a key species for defining the base of the Givetian, is evaluated.
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West Gondwanan aspects of the Middle and Upper Devonian Miospore Zonation in North Africa and Brazil.
Review of Palaeobotany and Palynology, 1995Co-Authors: Stanislas Loboziak, Maurice StreelAbstract:Abstract The stratigraphical distribution of 11 Miospore species found so far only in North Africa and Brazil are compared to the range of taxa which characterize the west European based zonation in order to establish accurate determinations. The zonate-camerate Miospores that are more or less restricted to the Middle Devonian are the most frequent. Other taxa, often camerate with some tabulate ornamentation, first occur near the Givetian-Frasnian boundary. Three of them are restricted to Brazil. These species are more abundant in the early Givetian. During the late Givetian they are probably more numerous in North Africa than in Brazil. Their relative frequencies strongly decrease during the Frasnian. A greater climatic contrast between the two regions during the late Eifelian (?) and the late Givetian and Frasnian than during the early Givetian is inferred.
Claudia V. Rubinstein - One of the best experts on this subject based on the ideXlab platform.
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Early Devonian organic-walled phytoplankton and Miospores from the Precordillera Basin of San Juan, Argentina: biostratigraphic and paleobiogeographic implications
Palynology, 2017Co-Authors: Victoria J. García Muro, Claudia V. Rubinstein, Juan José RustánAbstract:ABSTRACTThe palynological assemblages of the Talacasto and Punta Negra formations, from the Argentinean Precordillera, were analysed. Marine phytoplankton is dominant in both stratigraphic units. ?Cymatiosphaera florida, Evittia sommeri, Palacanthus ledanoisii, Riculasphaera fissa, Schizocystia pilosa, Tysanoprobolus polykion and Winwaloeusia distracta are among the most age-significant phytoplankton species of the Talacasto Formation, while Amicosporites sp. cf. A. streelii, Dictyotriletes emsiensis Morphon, Dictyotriletes favosus and ?Knoxisporites riondae prove the most biostratigraphically significant Miospore species. A Lochkovian to probably late Pragian age is interpreted based on the marine and terrestrial palynomorphs. The lower part of the Punta Negra Formation contains phytoplankton species such as Cordobesia oriental, Cordobesia uruguayensis, Duvernaysphaera stellata, Navifusa bacilla, Polyedryxium fragosulum and Pterospermella sp. cf. P. pernambucensis as well as the Miospores Acinosporites s...
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Palynostratigraphy of the Zorritas Formation, Antofagasta region, Chile: Insights on the Devonian/Carboniferous boundary in western Gondwana
Geoscience Frontiers, 2017Co-Authors: Claudia V. Rubinstein, Elodie Petus, Hans NiemeyerAbstract:Abstract The Middle Member of the Zorritas Formation in the Antofagasta region of northern Chile, yielded terrestrial and marine palynomorph assemblages which span the Devonian/Carboniferous boundary. The assemblages show a clear predominance of terrestrial palynomorphs with 70 Miospore species, 18 marine phytoplankton species, two non-marine algae and one chitinozoan species, all coming from 15 productive levels. Palynomorphs are poorly preserved and most of them are reworked. Three palynological associations are recognized based on Miospores. These are assigned to the Tournaisian–Visean, Tournaisian and probable latest Famennian. Age assignments are discussed in the frame of the spore zonal schemes established for Euramerica and western Gondwana. The stratigraphical distribution of spores allows the identification of the probable position of the Devonian/Carboniferous boundary within the Zorritas Formation. This system boundary is proposed for the first time in Palaeozoic sedimentary rocks of northern Chile. The presence of Gondwanan typical Miospore species indicates affinities with this palaeocontinent even though the Tournaisian and Tournaisian–Visean Miospore associations support the cosmopolitanism already suggested for the early Carboniferous flora. The significant number of reworked palynomorphs together with the sedimentological analysis of the studied sections, suggest that these deposits were severely impacted by the climatic change and major sea level fluctuations. Similar conditions were recorded in coeval western Gondwana basins.
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Upper Silurian Miospores from the Precordillera Basin, Argentina: biostratigraphic, palaeonvironmental and palaeogeographic implications
Geological Magazine, 2013Co-Authors: V.j. Garcia Muro, Claudia V. Rubinstein, Philippe SteemansAbstract:AbstractThis study is concentrated on Ludlow (to Pridoli?) Miospores from the Los Espejos Formation at the Quebrada Ancha locality, Central Precordillera, San Juan Province, Argentina. The Ludlow age is in agreement with the age based on acritarchs. The assemblage of continental palynomorphs is composed of 43 Miospore species (29 trilete spores and 14 cryptospores). A new synonymy is proposed: Chelinospora poecilomorpha is here considered a junior synonym of Clivosispora verrucata. In addition, specimens belonging to C. verrucata var. verrucata and C. verrucata var. convoluta are included in a new morphon. This study represents the second Late Silurian Miospore assemblage described from South America; the first was from the Urubu River, Amazon Basin, northern Brazil. The Quebrada Ancha assemblages allow a reasonably good correlation with biozones established for the Upper Silurian from the Cantabrian Mountains, northern Spain. The dendrogram analysis between coeval Miospore assemblages from different localities shows a strong palaeogeographic affinity with the Miospores recovered from northern Brazil and North Africa. Miospore assemblages from Spain show influences from Baltica and North Africa, demonstrating their intermediate position between these two continental plates. Conversely, dissimilarities recognized between Libya and Tunisia are most probably owing to local ecology and/or environmental conditions.
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Miospores from Ordovician-Silurian Argentinean basins: evolution and relationships with other South American basins
2011Co-Authors: Claudia V. Rubinstein, Victoria J. García Muro, Philippe SteemansAbstract:Miospores from Ordovician-Silurian Argentinean basins: evolution and relationships with other South American basins Claudia V. Rubinstein 1 , Victoria J. Garcia Muro 1 and Philippe Steemans 2 1 Unidad de Paleopalinologia, Departamento de Paleontologia, IANIGLA, CCT- CONICET Mendoza. Av. Ruiz Leal s/n, Parque General San Martin, 5500, Mendoza, Argentina. 2 Paleobotanique, Paleopalynologie, Micropaleontologie (PPM), Department of Geology, University of Liege, B-18, Sart Tilman, 4000 Liege 1, Belgium E-mails: crubinstein@mendoza-conicet.gov.ar , vgarcia@mendoza-conicet.gov.ar , p.steemans@ulg.ac.be . The earliest evidence of land plants are cryptospores ( sensu Steemans 2000) from the Middle Ordovician (Dapingian) of the Sierras Subandinas (NW Argentina). No uncontroversial data are available for the time period ranging from the Darriwilian to the Katian. In the latest Ordovician deposits from the northwestern geological provinces of the Central Andean Basin (Puna, Cordillera Oriental and Sierras Subandinas), there are few cryptospores in the palynological associations from the glacial-related strata (Caspala and Zapla Formations). On the other hand, rich, diverse and well-preserved cryptospore assemblages are observed in the post Hirnantian glaciation levels (Salar del Rincon Formation). Lower Silurian cryptospores are known from the northwestern Argentina Basin and the Precordillera Basin, where they are preserved in marine sediments. The cryptospores are rare and no trilete spores have been observed. The low diversity of Miospores is most probably due to the marine nature of the environment of deposition. Very few palynological data exists from Wenlockian layers. The palynological assemblages are exclusively marine, coming from the Chacoparanense Basin and probably from the northwestern Central Andean Basin. The FAD of trilete spores in Argentina occurs in Ludlovian sediments. The extensive outcrops of the Ludlovian-early Devonian (locally) Los Espejos Formation, in the Precordillera Basin, represent a muddy shelf to inner shelf exposed to storm activity, and storm-dominated shoreface towards the top. They yielded rich and diverse palynomorph assemblages assigned to the Ludlovian. The marine phytoplankton clearly dominates throughout the entire stratigraphic unit, except for the upper productive levels near the Siluro-Devonian boundary in the Rio Jachal locality. Amicosporites cf. miserabilis , A . cf. streelii , Archaezonotriletes chulus Morphon, Chelinospora cf. cassicula , Ch. poecilomorpha , Ch. sanpetrensis , Clivosispora verucata var. verrucata , Retusotriletes cf. amazonensis and Synorisporites verrucatus are among the most relevant trilete spores. Cryptospores such as Artemopyra robusta , A. urubuense and Cymbohilates hystricosus are the most informative taxa. Similarities and differences mainly with Brazilian and Paraguayan assemblages are noticed. The recorded Miospore taxa of the Los Espejos Formation show differences with coeval assemblages, displaying evolutionary innovations that seem to appear firstly in the Precordillera Basin than in other regions. References Steemans, P. (2000). Miospore evolution from the Ordovician to the Silurian. Review of Palaeobotany and Palynology , 113, 189-196.
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siluro devonian Miospore biostratigraphy of the urubu river area western amazon basin northern brazil
Geobios, 2008Co-Authors: Philippe Steemans, Claudia V. Rubinstein, José Henrique G. MeloAbstract:Abstract Well-preserved Miospores have been observed in the Urubu River area from the western part of the Amazon Basin, northern Brazil, in rocks belonging to the uppermost Pitinga and Manacapuru Formations. A previous palynological work based on chitinozoans has dated these strata as Late Ludlow, Early Pridoli and Early Lochkovian. Although samples are relatively poor in Miospores, the present study reveals the most diversified Silurian–Earliest Lochkovian palynoflora ever reported from South America, an interval where Miospore information is still very rare. Sixty-four species have been identified, of which two are new ( Artemopyra urubuense and Retusotriletes amazonensis ). One single specimen attributed to the genus Grandispora , identical to unpublished forms identified by one of us (P.S.) in Lochkovian sections of Saudi Arabia, has been found in a Lochkovian sample from the Urubu River. These constitute the oldest geological record of Grandispora . Among the abundant acritarchs, specimens of the genus Schizocystia have been observed for the first time in pre-Devonian rocks. Although the Late Silurian–Early Lochkovian Miospore biostratigraphy is still in its infancy in South America, it seems that Amazon Basin assemblages do not show significant differences in composition in comparison to coeval palynofloras from other areas of northwestern Gondwana. This is surprising since the Miospore localities under consideration are widely distributed over high to low paleolatitudes, i.e. from cool temperate to dry subtropical belts. Conversely, Siluro-Devonian Gondwanan assemblages differ considerably from the contemporary palynofloras of the Old Red Sandstone Continent and adjacent areas, thus contradicting recent phytogeographic interpretations based on megafloras.