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Pedro Cózar – One of the best experts on this subject based on the ideXlab platform.

  • Mississippian-like rugose corals from a Bashkirian biostrome in the Tindouf Basin, S. Morocco
    Spanish Journal of Palaeontology, 2020
    Co-Authors: Sergio Rodríguez, Ian D. Somerville, Ismail Said, Pedro Cózar

    Abstract:

    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

  • 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, 2018
    Co-Authors: Pedro Cózar, Ian D. Somerville, Silvia Blanco-ferrera, Javier Sanz-lópez

    Abstract:

    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.

  • The formation of the Alleghenian Isthmus triggered the Bashkirian glaciation: Constraints from warm-water benthic foraminifera
    Palaeogeography Palaeoclimatology Palaeoecology, 2017
    Co-Authors: Vladimir I. Davydov, Pedro Cózar

    Abstract:

    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.

Sanz-lópez Javier – One of the best experts on this subject based on the ideXlab platform.

  • Palaeobiogeographic context in the development of shallow-water late Viséan-early Bashkirian benthic foraminifers and calcareous algae in the Cantabrian Mountains (Spain)
    Elsevier, 2018
    Co-Authors: Cózar Pedro, Blanco-ferrera Silvia, Somerville Ian, Sanz-lópez Javier

    Abstract:

    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

  • Discovery of a Mississippian–early Bashkirian carbonate platform coeval with condensed cephalopod limestone sedimentation in NW Spain
    John Wiley & Sons, 2018
    Co-Authors: Sanz-lópez Javier, Cózar Pedro, Blanco-ferrera Silvia

    Abstract:

    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

  • Palaeobiogeographic context in the development of shallow-water late Viséan-early Bashkirian benthic foraminifers and calcareous algae in the Cantabrian Mountains (Spain)
    'Elsevier BV', 2018
    Co-Authors: Cozar Maldonado Pedro, Somerville, Ian D., Blanco-ferrerac Silvia, Sanz-lópez Javier

    Abstract:

    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.

  • Mississippian-Asselian (early carboniferous-early permian) foraminiferal faunas and biostratigraphy of the Shahreza-Abadeh regions (The Sanandaj-Sirjan Zone), Iran / Shirin Fassihi
    , 2017
    Co-Authors: Shirin Fassihi

    Abstract:

    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

  • fusulinoids from the Bashkirian moscovian transition beds of the shahreza region in the sanandaj sirjan zone iran
    International Journal of Earth Sciences, 2017
    Co-Authors: Shirin Fassihi, Masatoshi Sone, Vachik Hairapetian, Fariba Shirezadeh Esfahani

    Abstract:

    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.

  • Fusulinoids from the Bashkirian–Moscovian transition beds of the Shahreza region in the Sanandaj–Sirjan Zone, Iran
    International Journal of Earth Sciences, 2016
    Co-Authors: Shirin Fassihi, Masatoshi Sone, Vachik Hairapetian, Fariba Shirezadeh Esfahani

    Abstract:

    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.