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Josep Serra-kiel - One of the best experts on this subject based on the ideXlab platform.
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Carbonate ramp drowning caused by flexural subsidence: The South Pyrenean middle Eocene foreland basin
Sedimentary Geology, 2019Co-Authors: R. Silva-casal, Aitor Payros, Emilio L. Pueyo, Marc Aurell, Josep Serra-kielAbstract:Abstract A detailed sedimentological and magnetostratigraphic analysis of three selected sections of the Eocene carbonate platforms of the South Pyrenean Jaca-Pamplona foreland basin has been carried out in the Aragonese External Sierras (Huesca, Spain). The stratigraphic record spans from the middle-late Lutetian (Chron 20r, SBZ15) to the Bartonian (Chron 18r, SBZ17). The Lutetian-Bartonian transition was characterized by a major paleogeographic change, from a turbiditic foredeep with associated peripheral carbonate ramps to deltaic sedimentation. In most of the outcrops of the External Sierras, the peripheral carbonate platforms (Guara Formation) are overlained by prodelta and outer ramp marls (Arguis Formation). The drowning unconformity between these two formations in the outcrops located in the westernmost tip of the External Sierras is documented herein for the first time. In this area, the Guara Formation is overlain by glauconitic limestones deposited in a carbonate ramp setting. Between these units a characteristic unconformity is observed, with hard-ground formation and local evidence of subaerial exposure in the shallowest domains of the study area. The abundant glauconite found on top of this unconformity records a starvation period in the basin, followed by the development of a new carbonate ramp system during Bartonian times (Santo Domingo Member of the Arguis Formation). Magnetostratigraphic and sedimentological data show that tectonic tilting occurred in latest Lutetian times, prior to the drowning process. This suggests the influence of the flexural subsidence in the cratonic margin of the foreland as a result of the advance of a basement thrust in the hinterland. Nevertheless, the correlation of the uppermost Lutetian drowning unconformity with a basinwide regional sea level rise, which may have further been global, suggests an interplay between tectonic and eustatic processes in the drowning of the late Lutetian South Pyrenean carbonate ramps. In this work we point out a narrowing of the carbonate ramp, together with a relative sea level rise, as the processes responsible for the drowning of the Upper Guara Mb carbonate ramp. These processes could be responsible for the development of drowning unconformities in cratonic margins of other foreland basins. As carbonate ramps have a high sediment production potential, the narrowing of the carbonate factory could provide the conditions for the drowning of the carbonate ramp system in a subsequent sea level rise.
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Large scale facies change in the middle Eocene South-Pyrenean foreland basin: The role of tectonics and prelude to Cenozoic ice-ages
Sedimentary Geology, 2012Co-Authors: Damien Huyghe, Josep Serra-kiel, Sébastien Castelltort, Frédéric Mouthereau, Pierre-yves Filleaudeau, Laurent Emmanuel, Benoît Berthier, Maurice RenardAbstract:The present study reports a sedimentological analysis of the Guara Limestone Formation deposited during the Lutetian in the Sierras Exteriores, in the South-Pyrenean foreland basin. We provide a detailed facies analysis of the carbonates to precise the paleoenvironmental context during their deposition. We show that those limestones are mainly composed of shallow-water foraminifers and were deposited in relative shallow-water environments (< 120m) during the whole Lutetian (SBZ 13 to SBZ 16). The Guara Limestone Formation represents the last occurrence of carbonate platform in the South-Pyrenean foreland basin and disappeared definitely at the Lutetian to Bartonian transition. The demise of carbonate producers at the end of the Lutetian could be related to an increase of continental erosion, due to tectonic and/or climatic forcing. We illustrate that in the Jaca basin, this event correlates with a marked increase in subsidence rate. However, this deformation event is local and the carbonate systems in the Pyrenean foreland resisted to many deformation events during the whole basin history before. Paleobathymetric reconstructions in the Jaca basin, where shallow marine sections outcrop, suggest an increase of the amplitude of high-frequency sea-level cycles. This increase is contemporaneous with several climatic evidences, which suggest the appearance of early ice-sheets near the Lutetian-Bartonian boundary. The demise of carbonate producers seems, therefore, to be the result of a major environmental shift in the basin accompanying increased subsidence rates, switching from low nutrient oligotrophic conditions - favourable for shallow water benthic foraminifers - to eutrophic conditions due to the increase of erosion and terrigenous nutrient input associated with higher-frequency sea-level changes and river destabilization.
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Lutetian magnetostratigraphic calibration of larger foraminifera zonation (SBZ) in the Southern Pyrenees: The Isuela section
Palaeogeography Palaeoclimatology Palaeoecology, 2012Co-Authors: Adriana Rodríguez-pintó, Josep Serra-kiel, Emilio L. Pueyo, Antonio Barnolas, J.m. Samsó, Andrés PocovíAbstract:Abstract In this paper, we present a chronostratigraphic calibration of the shallow benthic zones (SBZs) of larger foraminifera during Lutetian times based on new magnetostratigraphic data (Isuela section) and two new densely sampled biostratigraphic sections (Isuela and Gabardiella). These sections are located in the External Sierras (Southern Pyrenees) and represent an ideal location to avoid previous chronostratigraphic problems. 1) They belong to a shallow carbonate shelf environment with abundant larger foraminifera, which ensure the reliability of SBZ data. 2) The time span covers almost the entire Lutetian interval. 3) The profiles are sufficiently long to establish trustworthy local scales, both the SBZs (520 m and 760 m in Isuela and Gabardiella respectively) and the paleomagnetic local polarity sequence (LPS) (520 m). 4) The excellent outcropping conditions also permit a detailed paleomagnetic and biostratigraphic sampling to be performed. The LPS at the Isuela section was built after sampling every 2.6 m. In total, more than 359 samples were thermal (244) and alternating field (115) demagnetized. Characteristic remanent magnetization (ChRM) usually dropped at 560 °C. Only 43% the samples (359 demagnetizations) gave reliable directions (high quality) for the LPS. A further short section (Gas line) was also cored (38 samples in 90 m) to obtain more detailed data for the upper part of the section. At the Isuela section, the results allow three pairs of trustable magnetozones to be assembled within the Lutetian. A further 255 samples were taken for biostratigraphic purposes, 55 sites at the Isuela and 52 at the Gabardiella sections being determinant. This density enabled a thorough study of changes in fossil associations to be performed. Assuming a constant accumulation rate within the chron boundaries, absolute ages have been estimated for the biostratigraphic boundaries. Combining all these data allows the previous calibration of SBZ during Lutetian times in the geological time scale to be refined. In particular, with this new data, we identify the SBZ 13/SBZ 14 boundary at 44.46 Ma reaching C20r; a boundary interval spanning from SBZ 14 to SBZ 15 (41.36 and 42.45 Ma) is found within C20n and C19n; and, finally, the top of SBZ 15 can be accurately located at 41.12 Ma (C19r).
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Large scale facies change in the middle Eocene South-Pyrenean foreland basin: The role of tectonics and prelude to Cenozoic ice-ages
Sedimentary Geology, 2012Co-Authors: Damien Huyghe, Josep Serra-kiel, Sébastien Castelltort, Frédéric Mouthereau, Pierre-yves Filleaudeau, Laurent Emmanuel, Benoît Berthier, Maurice RenardAbstract:International audienceThe present study reports a sedimentological analysis of the Guara Limestone Formation deposited during the Lutetian in the Sierras Exteriores, in the South-Pyrenean foreland basin. We provide a detailed facies analysis of the carbonates to precise the paleoenvironmental context during their deposition. We show that those limestones are mainly composed of shallow-water foraminifers and were deposited in relative shallow-water environments (< 120m) during the whole Lutetian (SBZ 13 to SBZ 16). The Guara Limestone Formation represents the last occurrence of carbonate platform in the South-Pyrenean foreland basin and disappeared definitely at the Lutetian to Bartonian transition. The demise of carbonate producers at the end of the Lutetian could be related to an increase of continental erosion, due to tectonic and/or climatic forcing. We illustrate that in the Jaca basin, this event correlates with a marked increase in subsidence rate. However, this deformation event is local and the carbonate systems in the Pyrenean foreland resisted to many deformation events during the whole basin history before. Paleobathymetric reconstructions in the Jaca basin, where shallow marine sections outcrop, suggest an increase of the amplitude of high-frequency sea-level cycles. This increase is contemporaneous with several climatic evidences, which suggest the appearance of early ice-sheets near the Lutetian-Bartonian boundary. The demise of carbonate producers seems, therefore, to be the result of a major environmental shift in the basin accompanying increased subsidence rates, switching from low nutrient oligotrophic conditions - favourable for shallow water benthic foraminifers - to eutrophic conditions due to the increase of erosion and terrigenous nutrient input associated with higher-frequency sea-level changes and river destabilization. © 2012 Elsevier B.V
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Marine and Transitional Middle/Upper Eocene Units of the Southeastern Pyrenean Foreland Basin (NE Spain)
Geologica Acta, 2003Co-Authors: Josep Serra-kiel, Anna Travé I Herrero, Emili Mató I Palós, Eloi Saula Briansó, Carles Ferrández I Cañadell, Pere Busquets, Josep Tosquella Angrill, Jaume Vergés I MasipAbstract:The stratigraphic basis of this work has allowed the use of larger foraminifers in the biostratigraphic characterisation of the new Shallow Benthic Zones (SBZ). This part of the volume presents a description of the sedimentary cycles formed by the transgressive-regressive systems of the Lutetian and Bartonian in the southeastern sector of the Ebro Foreland Basin.Concerning the Lutetian deposits studied in the Amer-Vic and Emporda areas, four sedimentary cycles have been characterised. The first and second are found within the Tavertet/Girona Limestone Formation (Reguant,1967;Palli,1972), while the third and fourth cycles cover the Coll de Malla Marl Formation (Clavell et al.,1970), the Bracons Formation (Gich,1969,1972), the Banyoles Marl Formation (Almela and Rios,1943),and the Bellmunt Formation (Gich,1969,1972). In the Bartonian deposits studied in the Igualada area,two transgressive-regressive sedimentary cycles have been characterised in the Collbas Formation (Ferrer,1971),the Igualada Formation (Ferrer,1971),and the Tossa Formation (Ferrer,1971). The Shallow Benthic Zones (SBZs)recognised within the Lutetian are the following:SBZ 13, from the Early Lutetian, in the transgressive system of the first cycle;SBZ 14,from the Middle Lutetian, in the second cycle and the lower part of the transgressive system of the third cycle; SBZ 15,from the Middle Lutetian, in the remaining parts of the third system; SBZ 16, from the Late Lutetian,throughout the fourth cycle.The association of larger foraminifers in the first and second cycles of the Bartonian in the Igualada area has been used as the basis for the definition of SBZs 17 and 18 recognised in the Bartonian of the western Tethys.
Maurice Renard - One of the best experts on this subject based on the ideXlab platform.
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Large scale facies change in the middle Eocene South-Pyrenean foreland basin: The role of tectonics and prelude to Cenozoic ice-ages
Sedimentary Geology, 2012Co-Authors: Damien Huyghe, Josep Serra-kiel, Sébastien Castelltort, Frédéric Mouthereau, Pierre-yves Filleaudeau, Laurent Emmanuel, Benoît Berthier, Maurice RenardAbstract:The present study reports a sedimentological analysis of the Guara Limestone Formation deposited during the Lutetian in the Sierras Exteriores, in the South-Pyrenean foreland basin. We provide a detailed facies analysis of the carbonates to precise the paleoenvironmental context during their deposition. We show that those limestones are mainly composed of shallow-water foraminifers and were deposited in relative shallow-water environments (< 120m) during the whole Lutetian (SBZ 13 to SBZ 16). The Guara Limestone Formation represents the last occurrence of carbonate platform in the South-Pyrenean foreland basin and disappeared definitely at the Lutetian to Bartonian transition. The demise of carbonate producers at the end of the Lutetian could be related to an increase of continental erosion, due to tectonic and/or climatic forcing. We illustrate that in the Jaca basin, this event correlates with a marked increase in subsidence rate. However, this deformation event is local and the carbonate systems in the Pyrenean foreland resisted to many deformation events during the whole basin history before. Paleobathymetric reconstructions in the Jaca basin, where shallow marine sections outcrop, suggest an increase of the amplitude of high-frequency sea-level cycles. This increase is contemporaneous with several climatic evidences, which suggest the appearance of early ice-sheets near the Lutetian-Bartonian boundary. The demise of carbonate producers seems, therefore, to be the result of a major environmental shift in the basin accompanying increased subsidence rates, switching from low nutrient oligotrophic conditions - favourable for shallow water benthic foraminifers - to eutrophic conditions due to the increase of erosion and terrigenous nutrient input associated with higher-frequency sea-level changes and river destabilization.
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Large scale facies change in the middle Eocene South-Pyrenean foreland basin: The role of tectonics and prelude to Cenozoic ice-ages
Sedimentary Geology, 2012Co-Authors: Damien Huyghe, Josep Serra-kiel, Sébastien Castelltort, Frédéric Mouthereau, Pierre-yves Filleaudeau, Laurent Emmanuel, Benoît Berthier, Maurice RenardAbstract:International audienceThe present study reports a sedimentological analysis of the Guara Limestone Formation deposited during the Lutetian in the Sierras Exteriores, in the South-Pyrenean foreland basin. We provide a detailed facies analysis of the carbonates to precise the paleoenvironmental context during their deposition. We show that those limestones are mainly composed of shallow-water foraminifers and were deposited in relative shallow-water environments (< 120m) during the whole Lutetian (SBZ 13 to SBZ 16). The Guara Limestone Formation represents the last occurrence of carbonate platform in the South-Pyrenean foreland basin and disappeared definitely at the Lutetian to Bartonian transition. The demise of carbonate producers at the end of the Lutetian could be related to an increase of continental erosion, due to tectonic and/or climatic forcing. We illustrate that in the Jaca basin, this event correlates with a marked increase in subsidence rate. However, this deformation event is local and the carbonate systems in the Pyrenean foreland resisted to many deformation events during the whole basin history before. Paleobathymetric reconstructions in the Jaca basin, where shallow marine sections outcrop, suggest an increase of the amplitude of high-frequency sea-level cycles. This increase is contemporaneous with several climatic evidences, which suggest the appearance of early ice-sheets near the Lutetian-Bartonian boundary. The demise of carbonate producers seems, therefore, to be the result of a major environmental shift in the basin accompanying increased subsidence rates, switching from low nutrient oligotrophic conditions - favourable for shallow water benthic foraminifers - to eutrophic conditions due to the increase of erosion and terrigenous nutrient input associated with higher-frequency sea-level changes and river destabilization. © 2012 Elsevier B.V
Damien Huyghe - One of the best experts on this subject based on the ideXlab platform.
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The Ostracod fauna from the outcroup "la falunière" of Grignon (Lutetian, Paris Basin): Stratigraphical implications
Geodiversitas, 2012Co-Authors: Claude Guernet, Damien Huyghe, Laurent Emmanuel, Franck Lartaud, Didier Merle, Jean-pierre Gély, Florent Michel, Ophélie PiletAbstract:The rehabilitation of the outcroup "la falunière" of Grignon (shell marl pit) allowed for the first time to take an almost complete section of the Paris Basin Middle Lutetian under its uncimented facies. It was the opportunity to undertake sedimentological and paleontological studies. This publication presents results of the ostracode study. More than 6000 valves or carapaces were collected and 87 species was distinguished. Three new species are described: Paracypris keiji n. sp., Neocytherideis labyrinthoidea n. sp. and Grinioneis pachycosta n. sp. The ostracodes vertical distribution in the faluns of Grignon is probably without stratigraphical signification. On the contrary, the Lutetian ostracodes associations are characteristic, as well in comparison with those of the Ypresian that with those of the Auversian or of the Barton beds. Specific diversification reflects that of the environmental niches and the wealth in individuals testify of the abundance of the food. Ostracodes indicate that the Lutetian sea was shallow, from some decimetres to some metres, probably, and its waters limpid, not much agitated. The summer temperature of water was equal at least to that of present Mediterranean Sea. From a paleogeographic point of view, the similarity between gallic fauna seems much more narrow than between whatever of this gallic fauna and those of the Aquitanian basin; so, the majority of English Lutetian species are known in the Paris Basin while the proportion of common species of the Paris Basin and of the North Aquitain basin is weak. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris.
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Middle Lutetian climate in the Paris Basin: implications for a marine hotspot of paleobiodiversity
Facies, 2012Co-Authors: Damien Huyghe, Franck Lartaud, Didier Merle, Emilie Cheype, Laurent EmmanuelAbstract:The present study reports the evolution of environmental conditions and seawater temperatures during the establishment of a marine hotspot of paleobiodiversity that took place in the Paris Basin during the Lutetian. The stable isotope compositions (δ^18O and δ^13C) of three species of molluscs (two bivalves: Cubitostrea plicata and Venericardia imbricata , and one gastropod: Sigmesalia multisulcata ) collected along the reference section of Grignon (Falunière) are used for paleoenvironmental and paleoclimatic reconstructions. Additional high-resolution analyses on one specimen of Haustator imbricatarius allow the documentation of seasonal changes for temperature. The high-resolution profiles of the δ^18O signatures of S. multisulcata reveal that these gastropods mineralized their shell during the warm months of the year, as did V. imbricata , which probably had a short life span (less than 1 year). These two species thus only yield temperatures for the summer period, from 22 to 30 °C. The δ^18O of C. plicata shells indicate mean annual sea surface temperatures ranging between 15 and 23 °C during the Middle Lutetian, with minimal temperatures probably reflecting greater depth at the base of the section. The seasonal contrasts reconstructed in the upper part of the section, from the large gastropod H. imbricatarius , ranged between 18 and 30 °C. Comparison of the isotopic values of the species indicates that the δ^13C of the three taxa seems to be mostly influenced by ecological features, leading to differences between endobenthic ( V. imbricata ) and epibenthic species ( C. plicata ); or the food habits. The paleoclimatic reconstructions show that the Lutetian climate was relatively stable in the Paris Basin with long-term cooling of the mean annual sea-surface temperatures. Nevertheless, this study shows that despite a context of colder conditions compared to the Early Eocene, the climate provided a favorable context for the increase of marine biodiversity in the Paris Basin during the Middle Lutetian.
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Large scale facies change in the middle Eocene South-Pyrenean foreland basin: The role of tectonics and prelude to Cenozoic ice-ages
Sedimentary Geology, 2012Co-Authors: Damien Huyghe, Josep Serra-kiel, Sébastien Castelltort, Frédéric Mouthereau, Pierre-yves Filleaudeau, Laurent Emmanuel, Benoît Berthier, Maurice RenardAbstract:The present study reports a sedimentological analysis of the Guara Limestone Formation deposited during the Lutetian in the Sierras Exteriores, in the South-Pyrenean foreland basin. We provide a detailed facies analysis of the carbonates to precise the paleoenvironmental context during their deposition. We show that those limestones are mainly composed of shallow-water foraminifers and were deposited in relative shallow-water environments (< 120m) during the whole Lutetian (SBZ 13 to SBZ 16). The Guara Limestone Formation represents the last occurrence of carbonate platform in the South-Pyrenean foreland basin and disappeared definitely at the Lutetian to Bartonian transition. The demise of carbonate producers at the end of the Lutetian could be related to an increase of continental erosion, due to tectonic and/or climatic forcing. We illustrate that in the Jaca basin, this event correlates with a marked increase in subsidence rate. However, this deformation event is local and the carbonate systems in the Pyrenean foreland resisted to many deformation events during the whole basin history before. Paleobathymetric reconstructions in the Jaca basin, where shallow marine sections outcrop, suggest an increase of the amplitude of high-frequency sea-level cycles. This increase is contemporaneous with several climatic evidences, which suggest the appearance of early ice-sheets near the Lutetian-Bartonian boundary. The demise of carbonate producers seems, therefore, to be the result of a major environmental shift in the basin accompanying increased subsidence rates, switching from low nutrient oligotrophic conditions - favourable for shallow water benthic foraminifers - to eutrophic conditions due to the increase of erosion and terrigenous nutrient input associated with higher-frequency sea-level changes and river destabilization.
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Middle Lutetian climate in the Paris Basin: implications for a marine hotspot of paleobiodiversity
Facies, 2012Co-Authors: Damien Huyghe, Franck Lartaud, Didier Merle, Emilie Cheype, Laurent EmmanuelAbstract:The present study reports the evolution of environmental conditions and seawater temperatures during the establishment of a marine hotspot of paleobiodiversity that took place in the Paris Basin during the Lutetian. The stable isotope compositions (δ18O and δ13C) of three species of molluscs (two bivalves: Cubitostrea plicata and Venericardia imbricata, and one gastropod: Sigmesalia multisulcata) collected along the reference section of Grignon (Faluniere) are used for paleoenvironmental and paleoclimatic reconstructions. Additional high-resolution analyses on one specimen of Haustator imbricatarius allow the documentation of seasonal changes for temperature. The high-resolution profiles of the δ18O signatures of S. multisulcata reveal that these gastropods mineralized their shell during the warm months of the year, as did V. imbricata, which probably had a short life span (less than 1 year). These two species thus only yield temperatures for the summer period, from 22 to 30 °C. The δ18O of C. plicata shells indicate mean annual sea surface temperatures ranging between 15 and 23 °C during the Middle Lutetian, with minimal temperatures probably reflecting greater depth at the base of the section. The seasonal contrasts reconstructed in the upper part of the section, from the large gastropod H. imbricatarius, ranged between 18 and 30 °C. Comparison of the isotopic values of the species indicates that the δ13C of the three taxa seems to be mostly influenced by ecological features, leading to differences between endobenthic (V. imbricata) and epibenthic species (C. plicata); or the food habits. The paleoclimatic reconstructions show that the Lutetian climate was relatively stable in the Paris Basin with long-term cooling of the mean annual sea-surface temperatures. Nevertheless, this study shows that despite a context of colder conditions compared to the Early Eocene, the climate provided a favorable context for the increase of marine biodiversity in the Paris Basin during the Middle Lutetian.
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Large scale facies change in the middle Eocene South-Pyrenean foreland basin: The role of tectonics and prelude to Cenozoic ice-ages
Sedimentary Geology, 2012Co-Authors: Damien Huyghe, Josep Serra-kiel, Sébastien Castelltort, Frédéric Mouthereau, Pierre-yves Filleaudeau, Laurent Emmanuel, Benoît Berthier, Maurice RenardAbstract:International audienceThe present study reports a sedimentological analysis of the Guara Limestone Formation deposited during the Lutetian in the Sierras Exteriores, in the South-Pyrenean foreland basin. We provide a detailed facies analysis of the carbonates to precise the paleoenvironmental context during their deposition. We show that those limestones are mainly composed of shallow-water foraminifers and were deposited in relative shallow-water environments (< 120m) during the whole Lutetian (SBZ 13 to SBZ 16). The Guara Limestone Formation represents the last occurrence of carbonate platform in the South-Pyrenean foreland basin and disappeared definitely at the Lutetian to Bartonian transition. The demise of carbonate producers at the end of the Lutetian could be related to an increase of continental erosion, due to tectonic and/or climatic forcing. We illustrate that in the Jaca basin, this event correlates with a marked increase in subsidence rate. However, this deformation event is local and the carbonate systems in the Pyrenean foreland resisted to many deformation events during the whole basin history before. Paleobathymetric reconstructions in the Jaca basin, where shallow marine sections outcrop, suggest an increase of the amplitude of high-frequency sea-level cycles. This increase is contemporaneous with several climatic evidences, which suggest the appearance of early ice-sheets near the Lutetian-Bartonian boundary. The demise of carbonate producers seems, therefore, to be the result of a major environmental shift in the basin accompanying increased subsidence rates, switching from low nutrient oligotrophic conditions - favourable for shallow water benthic foraminifers - to eutrophic conditions due to the increase of erosion and terrigenous nutrient input associated with higher-frequency sea-level changes and river destabilization. © 2012 Elsevier B.V
Aitor Payros - One of the best experts on this subject based on the ideXlab platform.
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Carbonate ramp drowning caused by flexural subsidence: The South Pyrenean middle Eocene foreland basin
Sedimentary Geology, 2019Co-Authors: R. Silva-casal, Aitor Payros, Emilio L. Pueyo, Marc Aurell, Josep Serra-kielAbstract:Abstract A detailed sedimentological and magnetostratigraphic analysis of three selected sections of the Eocene carbonate platforms of the South Pyrenean Jaca-Pamplona foreland basin has been carried out in the Aragonese External Sierras (Huesca, Spain). The stratigraphic record spans from the middle-late Lutetian (Chron 20r, SBZ15) to the Bartonian (Chron 18r, SBZ17). The Lutetian-Bartonian transition was characterized by a major paleogeographic change, from a turbiditic foredeep with associated peripheral carbonate ramps to deltaic sedimentation. In most of the outcrops of the External Sierras, the peripheral carbonate platforms (Guara Formation) are overlained by prodelta and outer ramp marls (Arguis Formation). The drowning unconformity between these two formations in the outcrops located in the westernmost tip of the External Sierras is documented herein for the first time. In this area, the Guara Formation is overlain by glauconitic limestones deposited in a carbonate ramp setting. Between these units a characteristic unconformity is observed, with hard-ground formation and local evidence of subaerial exposure in the shallowest domains of the study area. The abundant glauconite found on top of this unconformity records a starvation period in the basin, followed by the development of a new carbonate ramp system during Bartonian times (Santo Domingo Member of the Arguis Formation). Magnetostratigraphic and sedimentological data show that tectonic tilting occurred in latest Lutetian times, prior to the drowning process. This suggests the influence of the flexural subsidence in the cratonic margin of the foreland as a result of the advance of a basement thrust in the hinterland. Nevertheless, the correlation of the uppermost Lutetian drowning unconformity with a basinwide regional sea level rise, which may have further been global, suggests an interplay between tectonic and eustatic processes in the drowning of the late Lutetian South Pyrenean carbonate ramps. In this work we point out a narrowing of the carbonate ramp, together with a relative sea level rise, as the processes responsible for the drowning of the Upper Guara Mb carbonate ramp. These processes could be responsible for the development of drowning unconformities in cratonic margins of other foreland basins. As carbonate ramps have a high sediment production potential, the narrowing of the carbonate factory could provide the conditions for the drowning of the carbonate ramp system in a subsequent sea level rise.
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on the age of the early middle eocene boundary and other related events cyclostratigraphic refinements from the pyrenean otsakar section and the Lutetian gssp
Geological Magazine, 2011Co-Authors: Aitor Payros, Gilen Bernaola, Jaume Dinaresturell, Xabier Orueetxebarria, Estibaliz Apellaniz, Josep TosquellaAbstract:An integrated bio-, magneto- and cyclostratigraphic study of the Ypresian/Lutetian (Early/Middle Eocene) transition along the Otsakar section resulted in the identification of the C22n/C21r chron boundary and of the calcareous nannofossil CP12a/b zonal boundary; the latter is the main correlation criterion of the Lutetian Global Stratotype Section and Point (GSSP) recently defined at Gorrondatxe (Basque Country). By counting precession-related mudstone–marl couplets of 21 ka, the time lapse between both events was calculated to be 819 ka. This suggests that the age of the CP12a/b boundary, and hence that of the Early/Middle Eocene boundary, is 47.76 Ma, 250 ka younger than previously thought. This age agrees with, and is supported by, estimates from Gorrondatxe based on the time lapse between the Lutetian GSSP and the C21r/C21n boundary. The duration of Chron C21r is estimated at 1.326 Ma. Given that the base of the Eocene is dated at 55.8 Ma, the duration of the Early Eocene is 8 Ma, 0.8 Ma longer than in current time scales. The Otsakar results further show that the bases of planktonic foraminiferal zones E8 and P10 are younger than the CP12a/b boundary. The first occurrence of Turborotalia frontosa , being approximately 550 ka older that the CP12a/b boundary, is the planktonic foraminiferal event that lies closest to the Early/Middle Eocene boundary. The larger foraminiferal SBZ12/13 boundary is located close to the CP12a/b boundary and correlates with Chron C21r, not with the C22n/C21r boundary.
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On the age of the Early/Middle Eocene boundary and other related events: cyclostratigraphic refinements from the Pyrenean Otsakar section and the Lutetian GSSP
Geological Magazine, 2010Co-Authors: Aitor Payros, Gilen Bernaola, Jaume Dinarès-turell, Xabier Orue-etxebarria, Estibaliz Apellaniz, Josep TosquellaAbstract:An integrated bio-, magneto- and cyclostratigraphic study of the Ypresian/Lutetian (Early/Middle Eocene) transition along the Otsakar section resulted in the identification of the C22n/C21r chron boundary and of the calcareous nannofossil CP12a/b zonal boundary; the latter is the main correlation criterion of the Lutetian Global Stratotype Section and Point (GSSP) recently defined at Gorrondatxe (Basque Country). By counting precession-related mudstone–marl couplets of 21 ka, the time lapse between both events was calculated to be 819 ka. This suggests that the age of the CP12a/b boundary, and hence that of the Early/Middle Eocene boundary, is 47.76 Ma, 250 ka younger than previously thought. This age agrees with, and is supported by, estimates from Gorrondatxe based on the time lapse between the Lutetian GSSP and the C21r/C21n boundary. The duration of Chron C21r is estimated at 1.326 Ma. Given that the base of the Eocene is dated at 55.8 Ma, the duration of the Early Eocene is 8 Ma, 0.8 Ma longer than in current time scales. The Otsakar results further show that the bases of planktonic foraminiferal zones E8 and P10 are younger than the CP12a/b boundary. The first occurrence of Turborotalia frontosa , being approximately 550 ka older that the CP12a/b boundary, is the planktonic foraminiferal event that lies closest to the Early/Middle Eocene boundary. The larger foraminiferal SBZ12/13 boundary is located close to the CP12a/b boundary and correlates with Chron C21r, not with the C22n/C21r boundary.
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New fossils of Sirenia from the Middle Eocene of Navarre (Western Pyrenees): the oldest West European sea cow record
Geological Magazine, 2010Co-Authors: Humberto Astibia, Aitor Payros, Josep Tosquella, Nathalie Bardet, Xabier Pereda-suberbiola, V. De Buffrénil, Javier Elorza, Ana Berreteaga, Ainara BadiolaAbstract:Postcranial remains of Sirenia from the early Middle Eocene (late Lutetian) Urbasa-Andia Formation of Navarre (Western Pyrenees) are described. The material consists of two partial atlas vertebrae, one humerus and several dorsal ribs (from Arrasate, Urbasa plateau), and partial dorsal ribs (from Lezaun, Andia plateau). The morphology of the fossils is consistent with referral to Dugongidae, the only sirenian clade known so far in the Middle Eocene of Europe. Moreover, the histological study of the ribs shows that the pachyosteosclerosis of extant Sirenia was definitively present by the early Middle Eocene. The oldest sirenian remains reported to date in the Pyrenean Realm were assigned to the Biarritzian, a regional stage that is currently ascribed either to the middle or to the lower–middle Bartonian. Therefore, the sirenian remains of Lezaun, reliably dated as late Lutetian (SBZ16 zone) in age, are definitively the earliest sirenian fossils known in Western Europe and are among the oldest sea cow records of Europe.
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filling the north european early middle eocene ypresian Lutetian boundary gap insights from the pyrenean continental to deep marine record
Palaeogeography Palaeoclimatology Palaeoecology, 2009Co-Authors: Aitor Payros, Josep Tosquella, Gilen Bernaola, Jaume Dinaresturell, Xabier Orueetxebarria, Victoriano PujalteAbstract:Abstract The Early/Middle Eocene (Ypresian/Lutetian) transition is represented by a hiatus in many North European sections, including those in which the classic stratotypes were originally defined. However, the Global Stratotype Section and Point of the Lutetian Stage, which is still pending definition, should be placed at a globally correlatable event included within that unrepresented interval. The Pyrenean Eocene outcrops display sedimentary successions that offer the rare opportunity to analyse the Ypresian/Lutetian boundary interval in almost continuous sections and in very different settings. Seven reference stratigraphic sections were selected on the basis of their quality and correlated by means of biomagnetostratigraphic data. This correlation framework casts light on the sequence of chronostratigraphic events that characterize the Ypresian/Lutetian boundary interval, which may prove useful in defining the main correlation criterion of the base of the Lutetian. All of the Pyrenean sections show a similar sedimentary evolution, despite being up to 350 km apart from each other, containing deposits of different origins (intrabasinal carbonate sediments, siliciclastic sediments sourced from the Iberian plate, and terrigenous sediments sourced from the uplifting Pyrenees) and despite having been accumulated in different sedimentary environments (from continental to deep marine) and in different geodynamic settings (piggy-back basin, foreland basin and cratonic margin). This common evolution can be readily interpreted in terms of a sea-level driven depositional sequence whose lowstand and transgressive systems tracts are included within the Ypresian/Lutetian boundary interval. The Pyrenean Ypresian/Lutetian depositional sequence can reasonably be correlated with depositional sequences from classic North European areas, shedding light on the palaeoenvironmental history which in those areas has not been recorded. Furthermore, these depositional sequences may possibly correlate with others from the Antarctic Ocean and from New Jersey, as well as with oceanic temperature variations, suggesting that they might be the result of climatically-driven glacioeustatic sea-level changes. Should this hypothesis prove correct, it would confirm previous suggestions that the onset of Antarctic glaciations needs to be backshifted to the late Ypresian at least.
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on the age of the early middle eocene boundary and other related events cyclostratigraphic refinements from the pyrenean otsakar section and the Lutetian gssp
Geological Magazine, 2011Co-Authors: Aitor Payros, Gilen Bernaola, Jaume Dinaresturell, Xabier Orueetxebarria, Estibaliz Apellaniz, Josep TosquellaAbstract:An integrated bio-, magneto- and cyclostratigraphic study of the Ypresian/Lutetian (Early/Middle Eocene) transition along the Otsakar section resulted in the identification of the C22n/C21r chron boundary and of the calcareous nannofossil CP12a/b zonal boundary; the latter is the main correlation criterion of the Lutetian Global Stratotype Section and Point (GSSP) recently defined at Gorrondatxe (Basque Country). By counting precession-related mudstone–marl couplets of 21 ka, the time lapse between both events was calculated to be 819 ka. This suggests that the age of the CP12a/b boundary, and hence that of the Early/Middle Eocene boundary, is 47.76 Ma, 250 ka younger than previously thought. This age agrees with, and is supported by, estimates from Gorrondatxe based on the time lapse between the Lutetian GSSP and the C21r/C21n boundary. The duration of Chron C21r is estimated at 1.326 Ma. Given that the base of the Eocene is dated at 55.8 Ma, the duration of the Early Eocene is 8 Ma, 0.8 Ma longer than in current time scales. The Otsakar results further show that the bases of planktonic foraminiferal zones E8 and P10 are younger than the CP12a/b boundary. The first occurrence of Turborotalia frontosa , being approximately 550 ka older that the CP12a/b boundary, is the planktonic foraminiferal event that lies closest to the Early/Middle Eocene boundary. The larger foraminiferal SBZ12/13 boundary is located close to the CP12a/b boundary and correlates with Chron C21r, not with the C22n/C21r boundary.
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On the age of the Early/Middle Eocene boundary and other related events: cyclostratigraphic refinements from the Pyrenean Otsakar section and the Lutetian GSSP
Geological Magazine, 2010Co-Authors: Aitor Payros, Gilen Bernaola, Jaume Dinarès-turell, Xabier Orue-etxebarria, Estibaliz Apellaniz, Josep TosquellaAbstract:An integrated bio-, magneto- and cyclostratigraphic study of the Ypresian/Lutetian (Early/Middle Eocene) transition along the Otsakar section resulted in the identification of the C22n/C21r chron boundary and of the calcareous nannofossil CP12a/b zonal boundary; the latter is the main correlation criterion of the Lutetian Global Stratotype Section and Point (GSSP) recently defined at Gorrondatxe (Basque Country). By counting precession-related mudstone–marl couplets of 21 ka, the time lapse between both events was calculated to be 819 ka. This suggests that the age of the CP12a/b boundary, and hence that of the Early/Middle Eocene boundary, is 47.76 Ma, 250 ka younger than previously thought. This age agrees with, and is supported by, estimates from Gorrondatxe based on the time lapse between the Lutetian GSSP and the C21r/C21n boundary. The duration of Chron C21r is estimated at 1.326 Ma. Given that the base of the Eocene is dated at 55.8 Ma, the duration of the Early Eocene is 8 Ma, 0.8 Ma longer than in current time scales. The Otsakar results further show that the bases of planktonic foraminiferal zones E8 and P10 are younger than the CP12a/b boundary. The first occurrence of Turborotalia frontosa , being approximately 550 ka older that the CP12a/b boundary, is the planktonic foraminiferal event that lies closest to the Early/Middle Eocene boundary. The larger foraminiferal SBZ12/13 boundary is located close to the CP12a/b boundary and correlates with Chron C21r, not with the C22n/C21r boundary.
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New fossils of Sirenia from the Middle Eocene of Navarre (Western Pyrenees): the oldest West European sea cow record
Geological Magazine, 2010Co-Authors: Humberto Astibia, Aitor Payros, Josep Tosquella, Nathalie Bardet, Xabier Pereda-suberbiola, V. De Buffrénil, Javier Elorza, Ana Berreteaga, Ainara BadiolaAbstract:Postcranial remains of Sirenia from the early Middle Eocene (late Lutetian) Urbasa-Andia Formation of Navarre (Western Pyrenees) are described. The material consists of two partial atlas vertebrae, one humerus and several dorsal ribs (from Arrasate, Urbasa plateau), and partial dorsal ribs (from Lezaun, Andia plateau). The morphology of the fossils is consistent with referral to Dugongidae, the only sirenian clade known so far in the Middle Eocene of Europe. Moreover, the histological study of the ribs shows that the pachyosteosclerosis of extant Sirenia was definitively present by the early Middle Eocene. The oldest sirenian remains reported to date in the Pyrenean Realm were assigned to the Biarritzian, a regional stage that is currently ascribed either to the middle or to the lower–middle Bartonian. Therefore, the sirenian remains of Lezaun, reliably dated as late Lutetian (SBZ16 zone) in age, are definitively the earliest sirenian fossils known in Western Europe and are among the oldest sea cow records of Europe.
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filling the north european early middle eocene ypresian Lutetian boundary gap insights from the pyrenean continental to deep marine record
Palaeogeography Palaeoclimatology Palaeoecology, 2009Co-Authors: Aitor Payros, Josep Tosquella, Gilen Bernaola, Jaume Dinaresturell, Xabier Orueetxebarria, Victoriano PujalteAbstract:Abstract The Early/Middle Eocene (Ypresian/Lutetian) transition is represented by a hiatus in many North European sections, including those in which the classic stratotypes were originally defined. However, the Global Stratotype Section and Point of the Lutetian Stage, which is still pending definition, should be placed at a globally correlatable event included within that unrepresented interval. The Pyrenean Eocene outcrops display sedimentary successions that offer the rare opportunity to analyse the Ypresian/Lutetian boundary interval in almost continuous sections and in very different settings. Seven reference stratigraphic sections were selected on the basis of their quality and correlated by means of biomagnetostratigraphic data. This correlation framework casts light on the sequence of chronostratigraphic events that characterize the Ypresian/Lutetian boundary interval, which may prove useful in defining the main correlation criterion of the base of the Lutetian. All of the Pyrenean sections show a similar sedimentary evolution, despite being up to 350 km apart from each other, containing deposits of different origins (intrabasinal carbonate sediments, siliciclastic sediments sourced from the Iberian plate, and terrigenous sediments sourced from the uplifting Pyrenees) and despite having been accumulated in different sedimentary environments (from continental to deep marine) and in different geodynamic settings (piggy-back basin, foreland basin and cratonic margin). This common evolution can be readily interpreted in terms of a sea-level driven depositional sequence whose lowstand and transgressive systems tracts are included within the Ypresian/Lutetian boundary interval. The Pyrenean Ypresian/Lutetian depositional sequence can reasonably be correlated with depositional sequences from classic North European areas, shedding light on the palaeoenvironmental history which in those areas has not been recorded. Furthermore, these depositional sequences may possibly correlate with others from the Antarctic Ocean and from New Jersey, as well as with oceanic temperature variations, suggesting that they might be the result of climatically-driven glacioeustatic sea-level changes. Should this hypothesis prove correct, it would confirm previous suggestions that the onset of Antarctic glaciations needs to be backshifted to the late Ypresian at least.
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Filling the North European Early/Middle Eocene (Ypresian/Lutetian) boundary gap: Insights from the Pyrenean continental to deep-marine record
Palaeogeography Palaeoclimatology Palaeoecology, 2009Co-Authors: Aitor Payros, Josep Tosquella, Gilen Bernaola, Jaume Dinarès-turell, Xabier Orue-etxebarria, Victoriano PujalteAbstract:The Early/Middle Eocene (Ypresian/Lutetian) transition is represented by a hiatus in many North European sections, including those in which the classic stratotypes were originally defined. However, the Global Stratotype Section and Point of the Lutetian Stage, which is still pending definition, should be placed at a globally correlatable event included within that unrepresented interval. The Pyrenean Eocene outcrops display sedimentary successions that offer the rare opportunity to analyse the Ypresian/Lutetian boundary interval in almost continuous sections and in very different settings. Seven reference stratigraphic sections were selected on the basis of their quality and correlated by means of biomagnetostratigraphic data. This correlation framework casts light on the sequence of chronostratigraphic events that characterize the Ypresian/Lutetian boundary interval, which may prove useful in defining the main correlation criterion of the base of the Lutetian. All of the Pyrenean sections show a similar sedimentary evolution, despite being up to 350 km apart from each other, containing deposits of different origins (intrabasinal carbonate sediments, siliciclastic sediments sourced from the Iberian plate, and terrigenous sediments sourced from the uplifting Pyrenees) and despite having been accumulated in different sedimentary environments (from continental to deep marine) and in different geodynamic settings (piggy-back basin, foreland basin and cratonic margin). This common evolution can be readily interpreted in terms of a sea-level driven depositional sequence whose lowstand and transgressive systems tracts are included within the Ypresian/Lutetian boundary interval. The Pyrenean Ypresian/Lutetian depositional sequence can reasonably be correlated with depositional sequences from classic North European areas, shedding light on the palaeoenvironmental history which in those areas has not been recorded. Furthermore, these depositional sequences may possibly correlate with others from the Antarctic Ocean and from New Jersey, as well as with oceanic temperature variations, suggesting that they might be the result of climatically-driven glacioeustatic sea-level changes. Should this hypothesis prove correct, it would confirm previous suggestions that the onset of Antarctic glaciations needs to be backshifted to the late Ypresian at least
