62 research outputs found

    Late Chattian larger foraminifera from the Prebetic Domain (SE Spain): New data on Shallow Benthic Zone 23

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    This study focuses on an Oligocene succession dominated by larger foraminifera and coralline algae in the Benitatxell Range (Prebetic Domain, southeastern Iberian Peninsula). The foraminiferal assemblage, studied in thin sections, and interpreted as Shallow Benthic Zone 23, late Chattian, includes: Austrotrillina asmariensis, Nephrolepidina spp., Eulepidina dilatata, E. elephantina, E. raulini, Amphistegina bohdanowiczi, A. mammilla, Operculina complanata, Nummulites cf. vascus, N. aff. kecskemetii, Heterostegina assilinoides, Spiroclypeus blanckenhorni, Cycloclypeus mediterraneus, Miogysinoides formosensis, Postmiogypsinella aff. intermedia, Neorotalia viennoti, Risananeiza pustulosa, and Victoriella conoidea. The Rebaldí section, a succession of late Oligocene limestones 3 km north of the Benitatxell section, shows a similar association with Peneroplis thomasi, A. asmariensis, M. complanatus, Neorotalia viennoti, N. lithothamnica, Heterostegina aff. assilinoides, Spiroclypeus blanckenhorni, Cycloclypeus mediterraneus, A. bohdanowiczi, and Risananeiza pustulosa; it is interpreted as the early part of SBZ 23. This section also contains Praebullalveolina aff. oligocenica, described from the early Rupelian of Turkey, and Schlumbergerina alveoliniformis, previously interpreted as Burdigalian-Recent. Prior to this work, Cycloclypeus mediterraneus was considered to go extinct and be replaced by C. eidae at the SBZ 22B-23 boundary. However, its presence in the Benitatxell and Rebaldí sections extends its range to the late Chattian in the Eastern Betics and indicates an asynchronous extinction in the Tethys. The presence of Amphistegina mammilla Fichtel and Moll 1798 in late Chattian deposits from the western Tethys contradicts the currently accepted hypothesis that places its origin in the Indo-Pacific province in the early Miocene, from where it would have migrated into the Parathethys during the middle Miocene. In addition, the biogeographic range of P. thomasi, A. asmariensis, and P. oligocenica is extended to the westernmost part of the Tethys.

    Foreword

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    Foreword

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    Marine and Transitional Middle/Upper Eocene Units of the Southeastern Pyrenean Foreland Basin (NE Spain)

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    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 Empordà areas, four sedimentary cycles have been characterised. The first and second are found within the Tavertet/Girona Limestone Formation (Reguant,1967;Pallí,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 Ríos,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 Collbàs 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

    Revision of the Maastrichtian-Palaeocene charophyte biostratigraphy of the Fontllonga reference section (southern Pyrenees, Catalonia, Spain)

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    The Fontllonga section is one of the best-known stratigraphic sections wordwide for the study of charophyte biostratigraphy of the Maastrichtian and lower Palaeocene. An updated proposal for the charophyte biostratigraphy of this section is presented after summarizing previous knowledge. The zone of Peckichara cancellata allows the upper Campanian–lowermost Maastrichtian to be characterised in the base of the section (La Maçana Formation). The Microchara punctata biozone represents most of the Maastrichtian (Figuerola Formation). Within this biozone, a Clavator ultimus subzone is proposed to improve characterisation of the lower and middle Maastrichtian. Both the upper and lower boundaries of the Microchara punctata biozone proposed in previous studies are modified based on new occurrences of the index species. A charophyte assemblage belonging to the Dughiella bacillaris biozone is reported for the first time from the middle of the section (Perauba Complex) and provides an age for this unit ranging from the upper Danian to lower Thanetian. A foraminifer assemblage found in the basal marine deposits above the non-marine succession of the Fontllonga section provides new biostratigraphic data to locate the upper boundary of the non-marine succession at least within the upper Thanetian

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

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    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)
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