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Pedro Cózar - One of the best experts on this subject based on the ideXlab platform.
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Mississippian-like rugose corals from a Bashkirian biostrome in the Tindouf Basin, S. Morocco
Spanish Journal of Palaeontology, 2020Co-Authors: Sergio Rodríguez, Ian D. Somerville, Ismail Said, Pedro CózarAbstract:A rich rugose coral assemblage has been recorded from a biostrome at the top of the Djebel Ouarkziz Fm. in the Tindouf Basin, S. Morocco. It is composed of 10 genera and 14 species, of which 5 are new: Dibunophyllum bipartitum, Arachnolasma sp., Palaeosmilia murchisoni, Palaeosmilia ressoti, Palastraea regia, Siphonodendron tindoufense sp. nov., Siphonodendron ouarkzizense sp. nov., Diphyphyllum maximum, Axophyllum moroccoense sp. nov., Gangamophyllum sp., Axoclisia sahariense sp. nov., Axoclisia cf. coronata, Actinocyathus sarytschevae and Actinocyathus mariae sp. nov. It represents essentially a Mississippian-type coral fauna but with some evolved species. However, its age, as determined by foraminifers, is early Bashkirian (Early Pennsylvanian). The presence of Mississippian-like corals in the Bashkirian indicates that the epicontinental basins in northern Gondwana (Saharan basins) were a refuge for coral faunas during the late Serpukhovian extinction event. The persistence of the Mississippian assemblages in the Bashkirian from northern Gondwana was probably due to a combination of warm waters and tectonic stability. The coral assemblage from the Tindouf biostrome is similar to those corals recorded from Ellesmere Island, Arctic Canada and Novaya Zemlya, Arctic Russia where similar tropical warm water conditions have been identified during the Bashkirian in the northern hemisphere
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Palaeobiogeographic context in the development of shallow-water late Viséan-early Bashkirian benthic foraminifers and calcareous algae in the Cantabrian Mountains (Spain)
Palaeogeography Palaeoclimatology Palaeoecology, 2018Co-Authors: Pedro Cózar, Ian D. Somerville, Silvia Blanco-ferrera, Javier Sanz-lópezAbstract:Abstract The late Visean to early Bashkirian shallow-water carbonate Valdediezma Platform in the Picos de Europa Province of the Cantabrian Zone, has been subdivided into eight microbiotic intervals by means of similarity clusters (using the Morisita coefficient). The most complete Visean-Bashkirian interval is represented in the Valdediezma Valley – Jitu l'Escarandi –road to Tresviso, where only the Steshevian to lower part of the Protvian (middle Serpukhovian) is missing. This interval is better represented in the Pompedrei Bridge to La Hermida composite section, and also in the deeper water section at Vegas de Sotres. These intervals contain a succession from the Mikhailovian (upper Visean) up to the Krasnopolyanian (lower Bashkirian). The assemblages of the Valdediezma Limestone show, comparatively, low similarity indices with the neighbouring basins in the collisional front in the western extremity of the Palaeotethys during the progression of the Variscan Orogeny. In this mobile belt, two domains are recognized; a western domain composed of outcrops in south-western Spain and in the Moroccan Meseta, and an eastern domain comprising basins located in southern France. Some basins, such as the Betic Cordillera, initially had more influence from the western domain, but later, during the late Serpukhovian, it is considered as being part of the eastern domain. The Valdediezma Platform foraminiferal and algal content is coincident with its location as an isolated platform, surrounded by deep-water seas, and with higher similarities with the eastern domain. Regional tectonic events are recognized from the late Visean onward, and they are mostly masked by the overprint of latest Pennsylvanian events. Facies changes are commonly observed, particularly at the base of the intervals, suggesting that facies control is the most important factor controlling the assemblages. It is considered that eustatic sea-level changes exerted a certain control on the assemblages.
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The formation of the Alleghenian Isthmus triggered the Bashkirian glaciation: Constraints from warm-water benthic foraminifera
Palaeogeography Palaeoclimatology Palaeoecology, 2017Co-Authors: Vladimir I. Davydov, Pedro CózarAbstract:Abstract The timing of the final collision of Laurentia and Gondwana as well as the disappearance of the gateway between the Rheic and Tethyan oceans are quite controversial and poorly established. Accurate constraints on the gateway closure are vitally important for the understanding of global sea-level fluctuations, ocean circulation, regional and global environments, salinity and reorganization of the thermohaline circulation in the western Tethys, the Bashkirian glacial episode and the overall decline of atmospheric CO 2 concentrations. Here we present a new approach by applying warm-water benthic foraminifera (WWBF) data to precisely constrain the Rheic-Tethys gateway (RTG) closure, utilizing taxonomic and statistical methods. The link to the RTG closure and the profound biotic transformations in the oceans, sea-level, and expansion of the Gondwana ice sheet are discussed herein. The WWBF records in the studied regions constrain the timing of the RTG disappearance and support a linkage between the appearance of the Alleghenian Isthmus and the onset of the Bashkirian glaciation.
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Upper Mississippian to lower Pennsylvanian biostratigraphic correlation of the Sahara Platform successions on the northern margin of Gondwana (Morocco, Algeria, Libya)
Gondwana Research, 2016Co-Authors: Pedro Cózar, Ian D. Somerville, Ismail Said, Daniel Vachard, Ismael Coronado, Alejandra García-frank, Paula Medina-varea, Begoña Del Moral, Sergio RodríguezAbstract:Abstract Revision of several important Carboniferous stratigraphic successions in basins in the Saharan Platform allows us to propose distinct biostratigraphical boundaries for the upper Visean, lower and upper Serpukhovian and lower Bashkirian, with the latter boundary separating upper Mississippian from lower Pennsylvanian strata. The boundaries are not only defined primarily by foraminifers but also incorporate ammonoid and conodont data. This study shows that the positioning of some boundaries differs significantly from previous studies in the region. For the studied interval, it can be recognized that two well-defined tectonic events were widespread in the entire Sahara Platform: a mostly late Visean event and a latest Serpukhovian–early Bashkirian event. Both tectonic events show a marked tendency to become younger eastward, and they are compared to the intra-Visean phase of the Variscan Orogeny and the main phase of this orogeny, respectively.
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Potential Foraminiferal Markers for the Visean–Serpukhovian and Serpukhovian–Bashkirian Boundaries—a Case-Study from Central Morocco
Journal of Paleontology, 2011Co-Authors: Pedro Cózar, Sergio Rodríguez, Ian D. Somerville, Ismail Said, Daniel Vachard, Paula Medina-varea, Mostafa BerkhliAbstract:The Carboniferous succession in Adarouch (Central Morocco, north of the Atlas Transform Fault) contains thick carbonate beds including upper Visean, Serpukhovian and basal Bashkirian rocks. Foraminifers enable precise recognition of the Visean/Serpukhovian (V/S), early/late Serpukhovian (eS/lS) and Serpukhovian/Bashkirian (S/B) boundaries. Insolentitheca horrida, Loeblichia ukrainica, “Millerella” spp. and Endostaffella? sp. 2 are regarded as regionally useful indices to the V/S boundary, whereas Eostaffellina spp., Eostaffella pseudostruvei and some evolved species of Archaediscus exhibit greater reliability for worldwide correlation of this level. Similarly, the eS/lS boundary is marked locally by Brenckleina rugosa, Eosigmoilina sp., and Monotaxinoides spp. and globally by Loeblichia minima, Bradyina cribrostomata, Plectostaffella spp., Eostaffellina “protvae” and “Turrispiroides”, and the S/B boundary is marked locally by Globivalulina bulloides and globally by Seminovella elegantula, and Novella?. Occurrences of these taxa in Morocco allow correlations with the Moscow Basin, the Urals, the Donetz Basin and North America. The Moroccan assemblages share few taxa in common with Saharan basins south of the Atlas Transform Fault. Correlations with western European basins are difficult because of the paucity in the latter of foraminiferal-bearing carbonate strata.
Sanz-lópez Javier - One of the best experts on this subject based on the ideXlab platform.
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Palaeobiogeographic context in the development of shallow-water late Viséan-early Bashkirian benthic foraminifers and calcareous algae in the Cantabrian Mountains (Spain)
Elsevier, 2018Co-Authors: Cózar Pedro, Blanco-ferrera Silvia, Somerville Ian, Sanz-lópez JavierAbstract:The late Viséan to early Bashkirian shallow-water carbonate Valdediezma Platform in the Picos de Europa Province of the Cantabrian Zone, has been subdivided into eight microbiotic intervals by means of similarity clusters (using the Morisita coefficient). The most complete Viséan-Bashkirian interval is represented in the Valdediezma Valley – Jitu l'Escarandi –road to Tresviso, where only the Steshevian to lower part of the Protvian (middle Serpukhovian) is missing. This interval is better represented in the Pompedrei Bridge to La Hermida composite section, and also in the deeper water section at Vegas de Sotres. These intervals contain a succession from the Mikhailovian (upper Viséan) up to the Krasnopolyanian (lower Bashkirian). The assemblages of the Valdediezma Limestone show, comparatively, low similarity indices with the neighbouring basins in the collisional front in the western extremity of the Palaeotethys during the progression of the Variscan Orogeny. In this mobile belt, two domains are recognized; a western domain composed of outcrops in south-western Spain and in the Moroccan Meseta, and an eastern domain comprising basins located in southern France. Some basins, such as the Betic Cordillera, initially had more influence from the western domain, but later, during the late Serpukhovian, it is considered as being part of the eastern domain. The Valdediezma Platform foraminiferal and algal content is coincident with its location as an isolated platform, surrounded by deep-water seas, and with higher similarities with the eastern domain. Regional tectonic events are recognized from the late Viséan onward, and they are mostly masked by the overprint of latest Pennsylvanian events. Facies changes are commonly observed, particularly at the base of the intervals, suggesting that facies control is the most important factor controlling the assemblages. It is considered that eustatic sea-level changes exerted a certain control on the assemblages.The authors are grateful to the financial support of the Spanish Ministerio de Economía y Competitividad (research project CGL2016-78738).Peer reviewe
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Discovery of a Mississippian–early Bashkirian carbonate platform coeval with condensed cephalopod limestone sedimentation in NW Spain
John Wiley & Sons, 2018Co-Authors: Sanz-lópez Javier, Cózar Pedro, Blanco-ferrera SilviaAbstract:A new Mississippian to early Bashkirian shallow‐water carbonate platform, the Valdediezma Limestone, is identified in the central–eastern part of the Picos de Europa tectonic unit of the Cantabrian Mountains. The oldest beds (probably late Tournaisian or early Viséan) are faulted above middle Cambrian rocks. Biostratigraphy based on conodont and foraminiferal faunas allows to differentiate the Viséan–early Bashkirian Valdediezma Limestone from younger Bashkirian and Moscovian shallow‐water platforms previously described in the same area (Valdeteja and Picos de Europa formations). The Valdediezma Limestone recorded the rapid growth of a carbonate platform contemporaneous to the extended sedimentation of the Mississippian condensed, cephalopod‐bearing, nodular carbonates of the Alba Formation in the adjacent deep‐water basin. The growth of the platform continued during the late Serpukhovian and early Bashkirian, when deep‐water carbonates of the Barcaliente Formation were deposited in a geographically restricted foreland basin, and siliciclastic deposits filled the foredeep in the south‐western margin of the Cantabrian Mountains. A sedimentary hiatus from the early Bashkirian to the late Moscovian occurs above the Valdediezma Limestone. The exhumed and eroded platform was buried by late Moscovian to Kasimovian strata when the Variscan deformation affected the Picos de Europa unit. The Valdediezma Limestone was deposited on an isolated platform that rarely is preserved in South Europe, where contemporary shallow‐water carbonates were eroded and reworked into the synorogenic siliciclastic deposits of flysch‐type facies.This research was supported by the project CGL2016‐78738 of the Spanish Ministry of Research and Innovation.Peer reviewe
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Palaeobiogeographic context in the development of shallow-water late Viséan-early Bashkirian benthic foraminifers and calcareous algae in the Cantabrian Mountains (Spain)
'Elsevier BV', 2018Co-Authors: Cozar Maldonado Pedro, Somerville, Ian D., Blanco-ferrerac Silvia, Sanz-lópez JavierAbstract:The late Viséan to early Bashkirian shallow-water carbonate Valdediezma Platform in the Picos de Europa Province of the Cantabrian Zone, has been subdivided into eight microbiotic intervals by means of similarity clusters (using the Morisita coefficient). The most complete Viséan-Bashkirian interval is represented in the Valdediezma Valley – Jitu l'Escarandi –road to Tresviso, where only the Steshevian to lower part of the Protvian (middle Serpukhovian) is missing. This interval is better represented in the Pompedrei Bridge to La Hermida composite section, and also in the deeper water section at Vegas de Sotres. These intervals contain a succession from the Mikhailovian (upper Viséan) up to the Krasnopolyanian (lower Bashkirian). The assemblages of the Valdediezma Limestone show, comparatively, low similarity indices with the neighbouring basins in the collisional front in the western extremity of the Palaeotethys during the progression of the Variscan Orogeny. In this mobile belt, two domains are recognized; a western domain composed of outcrops in south-western Spain and in the Moroccan Meseta, and an eastern domain comprising basins located in southern France. Some basins, such as the Betic Cordillera, initially had more influence from the western domain, but later, during the late Serpukhovian, it is considered as being part of the eastern domain. The Valdediezma Platform foraminiferal and algal content is coincident with its location as an isolated platform, surrounded by deep-water seas, and with higher similarities with the eastern domain. Regional tectonic events are recognized from the late Viséan onward, and they are mostly masked by the overprint of latest Pennsylvanian events. Facies changes are commonly observed, particularly at the base of the intervals, suggesting that facies control is the most important factor controlling the assemblages. It is considered that eustatic sea-level changes exerted a certain control on the assemblages
Shirin Fassihi - One of the best experts on this subject based on the ideXlab platform.
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Mississippian-Asselian (early carboniferous-early permian) foraminiferal faunas and biostratigraphy of the Shahreza-Abadeh regions (The Sanandaj-Sirjan Zone), Iran / Shirin Fassihi
2017Co-Authors: Shirin FassihiAbstract:The Mississippian‒Asselian (Early Carboniferous‒Early Permian) foraminiferal faunas and biostratigraphy were studied in three sections of the Shahreza‒Abadeh regions, in the Sanandaj-Sirjan Zone, in Iran. These sections with a thickness of about 528‒1180 m are mainly composed of the siliciclastics and fossiliferous carbonates carbonates, apparently deposited in a shallow-water environment. The studied successions consist of Carboniferous Shishtu and Sardar groups and the uppermost Carboniferous‒Lower Permian Anarak Group. The sequence in question contains 217 species belonging to 75 genera within the six foraminiferal zones; namely, (1) the Uralodiscus rotundus - Glomodiscus miloni zone of a Viséan age, (2) the Plectostaffella jakhensis - Eostaffella pseudostruvei zone of a Voznesenian (earliest Bashkirian) age, (3) the Tikhonovichiella tikhonovichi - Profusulinella (Depratina) prisca - Aljutovella spp. zone of a Melekessian‒Vereian (latest Bashkirian–earliest Moscovian) age, (4) the Beedeina samarica - Taitzehoella mutabilis zone of a late Kashirian age, (5) the Fusulinella (Fusulinella) pseudobocki zone of an early Podolskian age, and (6) the Praepseudofusulina kljasmica zone of a latest Gzhelian‒Asselian age. Among the identified foraminifers, 21 genera and 37 species are reported for the first time in the Sanandaj-Sirjan Zone. The foraminiferal zones and their characteristic index species allow to correlate the Mississippian–Asselian sequence in the Sanandaj-Sirjan Zone with the foraminiferal biozonation acknowledged for the Mississippian–Asselian in the the Russian Platform, Southern and Northern Urals, Istanbul Terrane, Eastern and Central Taurides (Turkey), and Western Europe. These new foraminiferal faunas, furthermore, share some common species with the concurrent faunas of the Alborz, East Iran, and Central Iran. In this study, the foraminiferal assemblages of the Voznesenian (earliest Bashkirian) age, the Melekessian‒Vereian (latest Bashkirian‒earliest Moscovian) age, and also the Biozone MFZ11B (late early Viséan) are reported for the first time in the Sanandaj-Sirjan Zone. The study also presents the occurrence of 19 species of foraminifers for the first time in Iran
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fusulinoids from the Bashkirian moscovian transition beds of the shahreza region in the sanandaj sirjan zone iran
International Journal of Earth Sciences, 2017Co-Authors: Shirin Fassihi, Masatoshi Sone, Vachik Hairapetian, Fariba Shirezadeh EsfahaniAbstract:The presence of the Bashkirian–Moscovian (lower Pennsylvanian) sequence with mixed siliciclastics and fossil-rich carbonates has long been known from the Sanandaj–Sirjan Zone in Iran. However, except for a few studies, its biostratigraphy was not previously investigated in detail. A fusulinoid fauna is recovered from newly measured section, which we named the Asad Abad II section. It is located near the Shahreza town in the Sanandaj–Sirjan Zone. The most important fusulinoids of this assemblage are Aljutovella cf. aljutovica Rauser-Chernosouva, Tikhonovichiella tikhonovichi (Rauser-Chernosouva), and Profusulinella (Depratina) prisca (Deprat); they occur in association with species of Ozawainella, Staffellaeformis, and Pseudostaffella. This fauna overall represents a fauna of the latest Bashkirian–earliest Moscovian transition period in the Sanandaj–Sirjan Zone. This new fusulinoid fauna shares some common species with the concurrent faunas of the Alborz, East Iran, and Central Iran. Furthermore, it can be easily compared with those of the Russian Platform, Southern and Northern Urals, and Central Taurides (Turkey). The four species of the current fauna, namely Eostaffella compressa Brazhnikova, E. primitiva (Dutkevich), Pseudostaffella timanica Rauser-Chernosouva, and Profusulinella postpararhombiformis Dzhenchuraeva are reported from Iran for the first time. This study also presents the first occurrence of the genera Aljutovella and Tikhonovichiella in the Sanandaj–Sirjan Zone of Iran.
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Fusulinoids from the Bashkirian–Moscovian transition beds of the Shahreza region in the Sanandaj–Sirjan Zone, Iran
International Journal of Earth Sciences, 2016Co-Authors: Shirin Fassihi, Masatoshi Sone, Vachik Hairapetian, Fariba Shirezadeh EsfahaniAbstract:The presence of the Bashkirian–Moscovian (lower Pennsylvanian) sequence with mixed siliciclastics and fossil-rich carbonates has long been known from the Sanandaj–Sirjan Zone in Iran. However, except for a few studies, its biostratigraphy was not previously investigated in detail. A fusulinoid fauna is recovered from newly measured section, which we named the Asad Abad II section. It is located near the Shahreza town in the Sanandaj–Sirjan Zone. The most important fusulinoids of this assemblage are Aljutovella cf. aljutovica Rauser-Chernosouva, Tikhonovichiella tikhonovichi (Rauser-Chernosouva), and Profusulinella (Depratina) prisca (Deprat); they occur in association with species of Ozawainella, Staffellaeformis, and Pseudostaffella. This fauna overall represents a fauna of the latest Bashkirian–earliest Moscovian transition period in the Sanandaj–Sirjan Zone. This new fusulinoid fauna shares some common species with the concurrent faunas of the Alborz, East Iran, and Central Iran. Furthermore, it can be easily compared with those of the Russian Platform, Southern and Northern Urals, and Central Taurides (Turkey). The four species of the current fauna, namely Eostaffella compressa Brazhnikova, E. primitiva (Dutkevich), Pseudostaffella timanica Rauser-Chernosouva, and Profusulinella postpararhombiformis Dzhenchuraeva are reported from Iran for the first time. This study also presents the first occurrence of the genera Aljutovella and Tikhonovichiella in the Sanandaj–Sirjan Zone of Iran.
Fariba Shirezadeh Esfahani - One of the best experts on this subject based on the ideXlab platform.
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fusulinoids from the Bashkirian moscovian transition beds of the shahreza region in the sanandaj sirjan zone iran
International Journal of Earth Sciences, 2017Co-Authors: Shirin Fassihi, Masatoshi Sone, Vachik Hairapetian, Fariba Shirezadeh EsfahaniAbstract:The presence of the Bashkirian–Moscovian (lower Pennsylvanian) sequence with mixed siliciclastics and fossil-rich carbonates has long been known from the Sanandaj–Sirjan Zone in Iran. However, except for a few studies, its biostratigraphy was not previously investigated in detail. A fusulinoid fauna is recovered from newly measured section, which we named the Asad Abad II section. It is located near the Shahreza town in the Sanandaj–Sirjan Zone. The most important fusulinoids of this assemblage are Aljutovella cf. aljutovica Rauser-Chernosouva, Tikhonovichiella tikhonovichi (Rauser-Chernosouva), and Profusulinella (Depratina) prisca (Deprat); they occur in association with species of Ozawainella, Staffellaeformis, and Pseudostaffella. This fauna overall represents a fauna of the latest Bashkirian–earliest Moscovian transition period in the Sanandaj–Sirjan Zone. This new fusulinoid fauna shares some common species with the concurrent faunas of the Alborz, East Iran, and Central Iran. Furthermore, it can be easily compared with those of the Russian Platform, Southern and Northern Urals, and Central Taurides (Turkey). The four species of the current fauna, namely Eostaffella compressa Brazhnikova, E. primitiva (Dutkevich), Pseudostaffella timanica Rauser-Chernosouva, and Profusulinella postpararhombiformis Dzhenchuraeva are reported from Iran for the first time. This study also presents the first occurrence of the genera Aljutovella and Tikhonovichiella in the Sanandaj–Sirjan Zone of Iran.
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Fusulinoids from the Bashkirian–Moscovian transition beds of the Shahreza region in the Sanandaj–Sirjan Zone, Iran
International Journal of Earth Sciences, 2016Co-Authors: Shirin Fassihi, Masatoshi Sone, Vachik Hairapetian, Fariba Shirezadeh EsfahaniAbstract:The presence of the Bashkirian–Moscovian (lower Pennsylvanian) sequence with mixed siliciclastics and fossil-rich carbonates has long been known from the Sanandaj–Sirjan Zone in Iran. However, except for a few studies, its biostratigraphy was not previously investigated in detail. A fusulinoid fauna is recovered from newly measured section, which we named the Asad Abad II section. It is located near the Shahreza town in the Sanandaj–Sirjan Zone. The most important fusulinoids of this assemblage are Aljutovella cf. aljutovica Rauser-Chernosouva, Tikhonovichiella tikhonovichi (Rauser-Chernosouva), and Profusulinella (Depratina) prisca (Deprat); they occur in association with species of Ozawainella, Staffellaeformis, and Pseudostaffella. This fauna overall represents a fauna of the latest Bashkirian–earliest Moscovian transition period in the Sanandaj–Sirjan Zone. This new fusulinoid fauna shares some common species with the concurrent faunas of the Alborz, East Iran, and Central Iran. Furthermore, it can be easily compared with those of the Russian Platform, Southern and Northern Urals, and Central Taurides (Turkey). The four species of the current fauna, namely Eostaffella compressa Brazhnikova, E. primitiva (Dutkevich), Pseudostaffella timanica Rauser-Chernosouva, and Profusulinella postpararhombiformis Dzhenchuraeva are reported from Iran for the first time. This study also presents the first occurrence of the genera Aljutovella and Tikhonovichiella in the Sanandaj–Sirjan Zone of Iran.
Elisa Villa - One of the best experts on this subject based on the ideXlab platform.
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fusulines from the Bashkirian moscovian transition in the carboniferous of the cantabrian zone nw spain
Journal of Foraminiferal Research, 2016Co-Authors: Elisa Villa, Oscar MerinotomeAbstract:The Moscovian stratoype is located at the Moscow Basin (western Russian Platform), where fusulines have traditionally been used to subdivide the stage and to trace its lower boundary. However, fusuline assemblages from the lower Moscovian and the underlying upper Bashkirian show differences in species composition throughout Eurasia and also worldwide that make it difficult to establish correlations with the Russian Platform. This paper describes the succession of fusuline faunas yielded by three Cantabrian Zone (NW Spain) sections exposing the Bashkirian/Moscovian transition. Los Tornos and La Camocha sections are particularly relevant for they contain a fusuline record that could fill, at least partially, a gap existing at the base of the Moscovian stage stratotype. Another section, the Santo Firme section, is of interest in that it contains a cinerite that provided a numerical age at a level within the Bashkirian/Moscovian transition. Forty-nine fusuline taxa belonging to the Profusulinella Zone are described from these three sections, including the new species Schubertella multiforme , Profusulinella martinezi , Aljutovella asturiensis , and Eowedekindellina solovievae . In spite of the differences mentioned, attempts are made to correlate the fusulines from the Cantabrian Zone with the fusuline biozones defined in relevant Carboniferous areas of Eastern Europe (Russian Platform, Urals, Donets Basin).
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FUSULINES FROM THE Bashkirian/MOSCOVIAN TRANSITION IN THE CARBONIFEROUS OF THE CANTABRIAN ZONE (NW SPAIN)
Journal of Foraminiferal Research, 2016Co-Authors: Elisa Villa, Oscar Merino-toméAbstract:The Moscovian stratoype is located at the Moscow Basin (western Russian Platform), where fusulines have traditionally been used to subdivide the stage and to trace its lower boundary. However, fusuline assemblages from the lower Moscovian and the underlying upper Bashkirian show differences in species composition throughout Eurasia and also worldwide that make it difficult to establish correlations with the Russian Platform. This paper describes the succession of fusuline faunas yielded by three Cantabrian Zone (NW Spain) sections exposing the Bashkirian/Moscovian transition. Los Tornos and La Camocha sections are particularly relevant for they contain a fusuline record that could fill, at least partially, a gap existing at the base of the Moscovian stage stratotype. Another section, the Santo Firme section, is of interest in that it contains a cinerite that provided a numerical age at a level within the Bashkirian/Moscovian transition. Forty-nine fusuline taxa belonging to the Profusulinella Zone are described from these three sections, including the new species Schubertella multiforme , Profusulinella martinezi , Aljutovella asturiensis , and Eowedekindellina solovievae . In spite of the differences mentioned, attempts are made to correlate the fusulines from the Cantabrian Zone with the fusuline biozones defined in relevant Carboniferous areas of Eastern Europe (Russian Platform, Urals, Donets Basin).
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Facies distribution of Fusulinida in a Bashkirian-Moscovian (Pennsylvanian) carbonate-platform top (Cantabrian Mountains, NW Spain)
Journal of Foraminiferal Research, 2005Co-Authors: Giovanna Della Porta, Elisa Villa, Jeroen A. M. KenterAbstract:The Sierra del Cuera (Cantabrian Mountains, Asturias, Spain) exhibits an exceptionally well-preserved upper Bashkirian-lower Moscovian succession of a high-relief carbonate platform with steep adjacent slope. During the late Bashkirian, the platform margin prograded rapidly basinward, and during the early Moscovian, platform aggradation increased. Fusulinida distributions have been estimated in three platform study windows representative of the Bashkirian and Moscovian lithofacies. Microbial boundstone accumulations at the platform margin and slope contain scarce fusulinoideans (particularly during the Moscovian aggradation, when water depth was relatively greater). Boundstones are characterized by tetrataxids, lasiodiscids, pseudoammodiscids, biseriamminids, endothyrids and palaeotextulariids. Grainstone units with sediments deposited above wave base are characterized by the predominance of Pseudoendothyra , Eostaffella (Bashkirian) or Profusulinella (Moscovian), Bradyina and palaeotextulariids. The open-marine facies, below effective wave-base but intermittently affected by storm currents, is enriched in endothyrids and palaeotextulariids in the Bashkirian part, and in Profusulinella , Eofusulina and Schubertella in the Moscovian part. The Moscovian facies, of lower energy and deeper water depth, contain some microbially precipitated micrite and have scarce Fusulinida, mostly represented by endothyrids, biseriamminids, and fusulinoideans ( Eostaffella , Ozawainella and Profusulinella ). Lagoonal open- to restricted-marine facies with beresellid algae contain Profusulinella , Schubertella and biseriamminids. Crinoidal packstones were deposited in moderate-energy settings close to the platform margin, below wave-base, and are characterized by Ozawainella , Eostaffella , palaeotextulariids and tetrataxids. These analyses show that fusulinid foraminifera inhabited mostly shallow and open-marine environments. Their distribution was controlled by depth-related variables, water energy and open-marine vs. restricted-marine conditions. Fusulinoideans increase in the Moscovian strata, and show different trends in the upper Bashkirian and lower Moscovian platforms, possibly because of: a) changes in the paleoecology of Fusulinida at the species level from the Bashkirian to the Moscovian; and/or b) variations in the depositional environments and physicochemical characteristics of seawater from the Bashkirian progradational phase to the Moscovian aggradational phase. Pseudoendothyra , Profusulinella , Schubertella , bradyinids and palaeotextulariids showed an affinity for high-energy settings. Profusulinella and Schubertella , however, preferred the shallowest facies and also tolerated restricted marine conditions. Eostaffella ’s distribution largely differs between the Bashkirian and Moscovian parts because it characterizes the high-energy grainstones of the upper Bashkirian and the open-marine, moderate- to low-energy environments of the lower Moscovian. Endothyrids were excluded from lagoonal environments with restricted circulation and abnormal salinity. Biseriamminids preferred open-marine, moderate- to low-energy settings with muddy substrates, but were not limited by water restriction. Greater tolerance to deeper, darker habitats was exhibited by lasiodiscids, pseudoammodiscids and tetrataxids, which occurred from the platform top down to 200 m depth on the Moscovian slope.
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microbial boundstone dominated carbonate slope upper carboniferous n spain microfacies lithofacies distribution and stratal geometry
Facies, 2003Co-Authors: Giovanna Della Porta, Juan R. Bahamonde, J A M Kenter, Adrian Immenhauser, Elisa VillaAbstract:The Carboniferous, particularly during the Serpukhovian and Bashkirian time, was a period of scarce shallow-water calcimicrobial-microbialite reef growth. Organic frameworks developed on high-rising platforms are, however, recorded in the Precaspian Basin subsurface, Kazakhstan, Russia, Japan and Spain and represent uncommon occurrences within the general trend of low accumulation rates and scarcity of shallow-water reefs. Sierra del Cuera (Cantabrian Mountains, N Spain) is a well-exposed high-rising carbonate platform of Late Carboniferous (Bashkirian-Moscovian) age with a microbial boundstone-dominated slope dipping from 20° up to 45°. Kilometer-scale continuous exposures allow the detailed documentation of slope geometry and lithofacies spatial distribution. This study aims to develop a depositional model of steep-margined Late Paleozoic platforms built by microbial carbonates and to contribute to the understanding of the controlling factors on lithofacies characteristics, stacking patterns, accumulation rates and evolution of the depositional architecture of systems, which differ from light-dependent coralgal platform margins.
