Las biozonas de nummulitidos del Paleoceno Superior-Eoceno Inferior de la Cuenca Pirenaica

A nummulitid biozonation for the Upper Paleocene-Lower Eocene Pyrenean Basin is proposed in this work, The main contributions are: a) a new biozone proposed for the early Thanetian, b) a better characterization of the late Thanetian biozone, and c) the recognition of  two different biozones within the Lower Ilerdian.The nummulitid biozones established for the Pyrenean Upper Paleocene-Lower Eocene interval were correlated with the corresponding larger foraminiferal biozones Shallow Benthic Zones (SBZ) and integrated in the standard Paleocene-Eocene Time Scale on the basis of magnetostratigraphic data from the Pyrenean Basin and by correlation with the biozonation of calcareous nannoplankton and planktonic foraminifera in the Eastern and Central part of Tethys.The new biozones defined for tbe Pyrenean Upper Paleocene-Lower Eocene are: Nummulites heberti-Ranikothalia sindensis (early Thanetian), N. catari-Assilina yvettae-A. azilensis (late Thanetian), N. gamardensis-A. dandotica (early Ilerdian l), N. bigurdensis-A. aff. Prisca (early Ilerdian 2), N. carcasonensis-A. arenensis (middle Ilerdian l), N. exilis-A. leymeriei (middle Ilerdian 2), N. involutus-A. pomeroli (late Ilerdian), N. planulatus-N. burdigalensis burdigalensis-A. placentula (early Cuisian), N. praelaevigatus-N, cantabricus-A. laxispira (middle Cuisian), and N. manfredi-N. campesinus-A. mnior (late Cuisian)

Fossil associations from the middle and upper Eocene strata of the Pamplona Basin and surrounding areas (Navarre, western Pyrenees)

Fossil associations from the middle and upper Eocene (Bartonian and Priabonian) sedimentary succession of the Pamplona Basin are described. This succession was accumulated in the western part of the South Pyrenean peripheral foreland basin and extends from deep-marine turbiditic (Ezkaba Sandstone Formation) to deltaic (Pamplona Marl, Ardanatz Sandstone and Ilundain Marl formations) and marginal marine deposits (Gendulain Formation). The micropalaeontological content is high. It is dominated by foraminifera, and common ostracods and other microfossils are also present. The fossil ichnoasssemblages include at least 23 ichnogenera and 28 ichnospecies indicative of Nereites, Cruziana, and ?Scoyenia-Mermia ichnofacies. Body macrofossils of about 80 taxa corresponding to macroforaminifera, sponges, corals, bryozoans, brachiopods, annelids, molluscs, arthropods, echinoderms and vertebrates have been identified. Both the number of ichnotaxa and of species (e. g. bryozoans, molluscs and condrichthyans) may be considerably higher. Body fossil assemblages are comparable to those from the Eocene of the Nord Pyrenean area (Basque Coast), and also to those from the Eocene of the west-central and eastern part of South Pyrenean area (Aragon and Catalonia). At the European scale, the molluscs assemblages seem endemic from the Pyrenean area, although several Tethyan (Italy and Alps) and Northern elements (Paris Basin and Normandy) have been recorded. Palaeontological data of studied sedimentary units fit well with the shallowing process that throughout the middle and late Eocene occurs in the area, according to the sedimentological and stratigraphical data.Se describen las asociaciones fósiles del Eoceno medio y superior (Bartoniense y Priaboniense) de la sucesión sedimentaria de la Cuenca de Pamplona. Esta sucesión se acumuló en la parte oeste de la Cuenca de antepaís periférica surpirenaica y comprende desde turbiditas marinas profundas (Formación Areniscas de Ezkaba) hasta depósitos deltaicos (Formaciones Margas de Pamplona, Areniscas de Ardanatz y Margas de Ilundain) y marinos marginales (Formación Gendulain). El contenido micropaleontológico es alto y está dominado por los foraminíferos. Los fósiles de ostrácodos y otros organismos son también abundantes. Las asociaciones de icnofósiles incluyen al menos 23 icnogéneros y 28 ichnoespecies, indicativas de las icnofacies de Nereites, Cruziana, y ?Scoyenia-Mermia. Se han identificado fósiles corporales de unos 80 taxones, correspondientes a macroforaminíferos, esponjas, corales, briozoos, braquiópodos, anélidos, moluscos, artrópodos, equinodermos y vertebrados. El número de icnotaxones y de especies (p. e. briozoos, moluscos gasterópodos, bivalvos y peces condríctios) puede ser considerablemente mayor. Las asociaciones de fósiles corporales son comparables a las del Eoceno del Área norpirenaica (Costa vasca) y de las partes central y este del Área surpirenaica (Aragón y Cataluña). A escala europea, la asociación de moluscos parece endémica del Área pirenaica, aunque contiene elementos del Tetis (Italia y Alpes) y de las cuencas del norte (Cuenca de París y Normandía). El contenido paleontológico de las unidades sedimentarias analizadas es coherente con el proceso de somerización que tiene lugar a lo largo del Eoceno medio y tardío, de acuerdo con lo que indican los datos sedimentológicos y estratigráficos.Comments by Dr. Kai Ingemann Schnetler and an anonymous reviewer considerably improved the manuscript. Financial support to H.A., A.Ba., A.Be., I. D.-M., J.E. and X.P.-S. was provided by the Project CGL2013-47521-P (Ministerio de Economia y Competitividad, Servicio de Estado de Investigacion, Desarrollo e Innovacion, MINECO, Spain), the European Regional Development Fund/Fondo Europeo de Desarrollo Regional (ERDF/FEDER), and the research group IT-834-13 (Eusko Jaurlaritza/Gobierno Vasco, EJ/GV). Research work of I.D.-M. was supported by a postdoctoral grant provided by the Ministerio de Ciencia, Tecnologia e Innovacion Productiva, Consejo Nacional de Investigaciones Cientificas y Tecnicas, Argentina. Financial support to F.J.R.-T. was provided by the Project CGL2012-33281 (Secretaria de Estado de I+D+I, MINECO, Spain), and the research group RNM-178 (Junta de Andalucia). A.P. and S.O. were funded by project CGL 2011-23770 (MINECO) and the research group IT-215-07 (EJ/GV)

Las biozonas de nummulitidos del Paleoceno Superior-Eoceno Inferior de la Cuenca Pirenaica

A nummulitid biozonation for the Upper Paleocene-Lower Eocene Pyrenean Basin is proposed in this work, The main contributions are: a) a new biozone proposed for the early Thanetian, b) a better characterization of the late Thanetian biozone, and c) the recognition of  two different biozones within the Lower Ilerdian.The nummulitid biozones established for the Pyrenean Upper Paleocene-Lower Eocene interval were correlated with the corresponding larger foraminiferal biozones Shallow Benthic Zones (SBZ) and integrated in the standard Paleocene-Eocene Time Scale on the basis of magnetostratigraphic data from the Pyrenean Basin and by correlation with the biozonation of calcareous nannoplankton and planktonic foraminifera in the Eastern and Central part of Tethys.The new biozones defined for tbe Pyrenean Upper Paleocene-Lower Eocene are: Nummulites heberti-Ranikothalia sindensis (early Thanetian), N. catari-Assilina yvettae-A. azilensis (late Thanetian), N. gamardensis-A. dandotica (early Ilerdian l), N. bigurdensis-A. aff. Prisca (early Ilerdian 2), N. carcasonensis-A. arenensis (middle Ilerdian l), N. exilis-A. leymeriei (middle Ilerdian 2), N. involutus-A. pomeroli (late Ilerdian), N. planulatus-N. burdigalensis burdigalensis-A. placentula (early Cuisian), N. praelaevigatus-N, cantabricus-A. laxispira (middle Cuisian), and N. manfredi-N. campesinus-A. mnior (late Cuisian)

The early/middle Eocene transition at the Ésera valley (South Central Pyrenees): Implications in Shallow Benthic Zones (SBZ)

An integrated study including magnetostratigraphy, larger benthic foraminifera and calcareous nannofossil biostratigraphy is presented herein. This work was performed in shallow marine siliciclastics rich in larger foraminifera, around the Ypresian/Lutetian boundary in the Ésera valley (South-Central Pyrenees). Although the calcareous nannofossil content in the studied interval is low, not allowing a precise Y/L boundary to be recognised, the taxa found are enough to support the chronostratigraphic attribution. Data obtained in the Ésera valley section has improved the knowledge of larger benthic foraminifera (Nummulites and Assilina) distribution through chron C21. SBZ 11 to SBZ 12 transition took place at the lowermost C21r, as shown in previous works. SBZ 12 assemblages extend into C21n, where the SBZ 12 to SBZ 13 boundary occurs. These data, obtained in shallow marine siliciclastic facies, with in situ fauna, results in a shift of the SBZ 12/SBZ 13 boundary to the Lower Lutetian, younger than previously believed. Accordingly, the Ypresian/Lutetian boundary occurs in SBZ 12

The early/middle Eocene transition at the Ésera valley (South Central Pyrenees): Implications in Shallow Benthic Zones (SBZ)

An integrated study including magnetostratigraphy, larger benthic foraminifera and calcareous nannofossil biostratigraphy is presented herein. This work was performed in shallow marine siliciclastics rich in larger foraminifera, around the Ypresian/Lutetian boundary in the Ésera valley (South-Central Pyrenees). Although the calcareous nannofossil content in the studied interval is low, not allowing a precise Y/L boundary to be recognised, the taxa found are enough to support the chronostratigraphic attribution. Data obtained in the Ésera valley section has improved the knowledge of larger benthic foraminifera (Nummulitesand Assilina) distribution through chron C21. SBZ 11 to SBZ 12 transition took place at the lowermost C21r, as shown in previous works. SBZ 12 assemblages extend into C21n, where the SBZ 12 to SBZ 13 boundary occurs. These data, obtained in shallow marine siliciclastic facies, with in situ fauna, results in a shift of the SBZ 12/SBZ 13 boundary to the Lower Lutetian, younger than previously believed. Accordingly, the Ypresian/Lutetian boundary occurs in SBZ 12

The early/middle Eocene transition at the Ésera valley (SouthCentral Pyrenees) : implications in Shallow Benthic Zones (SBZ)

Acknowledgement. AB fieldwork has been supported by the project PGC2018-093903-C1, additional support came from the projects DR3AM (CGL2014-54118-C2-2-R) MAGIBERII (CGL2017-90632-REDT) and UKRIA4D (PID2019-104693GB-I00/CTA) all of them from the Spanish Science National Plan. The study of calcareous nannofossils was supported by the Research Group of the Basque University System IT-1602-22. Pablo Calvín gave us a hand with the reversal test in Python. The accurate and constructive comments from Johannes Pignatti, Elisabet Beamud, the Journal Manager Laura Rincón, and the editors Carles Martín Closas, Eulàlia Gili and Miguel Garcés helped to improve the original manuscript.An integrated study including magnetostratigraphy, larger benthic foraminifera and calcareous nannofossil biostratigraphy is presented herein. This work was performed in shallow marine siliciclastics rich in larger foraminifera, around the Ypresian/Lutetian boundary in the Ésera valley (South-Central Pyrenees). Although the calcareous nannofossil content in the studied interval is low, not allowing a precise Y/L boundary to be recognised, the taxa found are enough to support the chronostratigraphic attribution. Data obtained in the Ésera valley section has improved the knowledge of larger benthic foraminifera (Nummulites and Assilina) distribution through chron C21. SBZ 11 to SBZ 12 transition took place at the lowermost C21r, as shown in previous works. SBZ 12 assemblages extend into C21n, where the SBZ 12 to SBZ 13 boundary occurs. These data, obtained in shallow marine siliciclastic facies, with in situ fauna, results in a shift of the SBZ 12/SBZ 13 boundary to the Lower Lutetian, younger than previously believed. Accordingly, the Ypresian/Lutetian boundary occurs in SBZ 12

The early/middle Eocene transition at the Ésera valley (SouthCentral Pyrenees) : implications in Shallow Benthic Zones (SBZ)

Acknowledgement. AB fieldwork has been supported by the project PGC2018-093903-C1, additional support came from the projects DR3AM (CGL2014-54118-C2-2-R) MAGIBERII (CGL2017-90632-REDT) and UKRIA4D (PID2019-104693GB-I00/CTA) all of them from the Spanish Science National Plan. The study of calcareous nannofossils was supported by the Research Group of the Basque University System IT-1602-22. Pablo Calvín gave us a hand with the reversal test in Python. The accurate and constructive comments from Johannes Pignatti, Elisabet Beamud, the Journal Manager Laura Rincón, and the editors Carles Martín Closas, Eulàlia Gili and Miguel Garcés helped to improve the original manuscript.An integrated study including magnetostratigraphy, larger benthic foraminifera and calcareous nannofossil biostratigraphy is presented herein. This work was performed in shallow marine siliciclastics rich in larger foraminifera, around the Ypresian/Lutetian boundary in the Ésera valley (South-Central Pyrenees). Although the calcareous nannofossil content in the studied interval is low, not allowing a precise Y/L boundary to be recognised, the taxa found are enough to support the chronostratigraphic attribution. Data obtained in the Ésera valley section has improved the knowledge of larger benthic foraminifera (Nummulites and Assilina) distribution through chron C21. SBZ 11 to SBZ 12 transition took place at the lowermost C21r, as shown in previous works. SBZ 12 assemblages extend into C21n, where the SBZ 12 to SBZ 13 boundary occurs. These data, obtained in shallow marine siliciclastic facies, with in situ fauna, results in a shift of the SBZ 12/SBZ 13 boundary to the Lower Lutetian, younger than previously believed. Accordingly, the Ypresian/Lutetian boundary occurs in SBZ 12

The Eocene carbonate platforms of the Ghomaride Domain (Internal Rif Zone, N Morocco): a segment of the westernmost Tethys

The Eocene platform deposits in the Moroccan Ghomarides have been studied. These marine carbonate platforms were located in the westernmost Tethys approximately 30°N and 0°–10°W during the Cuisian to Bartonian. The study includes observations from fossiliferous assemblages (such as larger benthic foraminifera and colonial corals), their palaeoenvironment as well as rock texture and fabric. Eight microfacies were identified that represent different ramp environments in a ‘distally-steepened carbonate ramp’ type of platform. The studied deposits are organised into a transgressive succession composed of three sedimentary cycles: lower Cuisian, middle Cuisian and middle Lutetian to Bartonian. In the lower cycle, photic inner to mid ramp environments in mesotrophic conditions were prevalent. In the second cycle, photic inner ramp (sea-grass) to mid ramp environments in mesotrophic to oligotrophic conditions were observed. The upper cycle, which is more extensive and variable, represents mesophotic mid ramp to aphotic slope environments and changes gradually from oligotrophic to eutrophic conditions. During the Eocene, larger benthic foraminifera were dominant overtaking the zooxanthellate corals in the Tethys regions. Nevertheless, our study and the performed comparison with other Tethyan sectors have revealed that in some areas both coexisted in similar proportions. In some western Tethys regions close to the Atlantic Ocean, coinciding with areas influenced by upwelling currents, larger benthic foraminifera and coral build-ups were replaced by oyster reefs. The Ghomaride Domain represents an intermediate case between fossil assemblages of the northern Tethyan margin and eastern sector of the southern margin of the Tethys, with a dominance of larger benthic foraminifera but with a certain presence of corals as well. A good correlation exists between Eocene warm intervals and carbonate platform deposits in these domains. Contrarily, during cooling ones shallowing and gaps in the sedimentation are registered. Two anomalies have been detected in the Ghomaride Domain during Ypresian and Bartonian times indicating particular climatic conditions or local tectonic interferences

The Eocene carbonate platforms of the Ghomaride Domain (Internal Rif Zone, N Morocco): A segment of the westernmost Tethys

The Eocene platforms deposits in the Moroccan Ghomarides have been studied in this paper. These marine carbonate platforms were located in the westernmost Tethys approximately 30°N and 0°–10°W during the Cuisian to Bartonian. This study includes observations from fossiliferous assemblages (such as larger benthic foraminifera and colonial corals), their paleoenvironment as well as rock texture and fabric. Eight microfacies were identified that represent different ramp environments in a ‘distally-steepened carbonate ramp’ type of platform. The studied deposits are organised into a transgressive succession composed of three sedimentary cycles: lower Cuisian, middle Cuisian and middle Lutetian to Bartonian. In the lower cycle, photic inner to middle ramp environments in mesotrophic conditions were prevalent. In the second cycle, photic inner ramp (sea-grass) to mid ramp environments in mesotrophic to oligotrophic conditions were observed. The upper cycle, which is more extensive and variable, represents mesophotic mid ramp to aphotic slope environments and change gradually from oligotrophic to eutrophic conditions. During the Eocene, larger benthic foraminifera were dominant overtaking the zooxanthellate corals in the Tethys regions. Nevertheless, our study and the performed comparison with other Tethyan sectors have revealed that in some areas both coexisted in similar proportions. In some western Tethys regions close to the Atlantic Ocean, coinciding with areas influenced by upwelling currents, larger benthic foraminifera and coral build-ups were replaced by oyster reefs. The Ghomaride Domain represents an intermediate case between fossil assemblages of northern Tethyan margin and eastern sector of the southern margin of the Tethys, with a dominance of larger benthic foraminifera but with a certain presence of corals as well. A good correlation exists between Eocene warm intervals and carbonate platform deposits in these domains. Contrarily, during cooling ones shallowing and gaps in the sedimentation is registered. Two anomalies have been detected in the Ghomaride Domain during Ypresian and Bartonian times indicating particular climatic conditions or local tectonics interferences.Research supported by: Research Project PID2020-114381GB-I00, Spanish Ministry of Science and Innovation; Research Groups and Projects from M. Martín-Martín, Alicante University (CTMA-IGA)