Larger Foraminiferal Biostratigraphy and Facies Analysis of the Oligocene-Miocene Asmari Formation in the Western Fars Sub-basin, Zagros Mountains, Iran

The Oligocene-Miocene carbonate record of the Zagros Mountains, known as the Asmari Formation, constitutes an important hydrocarbon reservoir in southern Iran. This marine carbonate succession, which developed under tropical conditions, is explored in terms of larger foraminiferal biostratigraphy, facies analysis and sequence stratigraphy in a new section at Papoon cropping out in the western Fars sub‐basin, in the south‐east of the Zagros belt. Facies analysis shows evidence of re‐working and transport of skeletal components throughout the depositional system, interpreted here as a carbonate ramp. The foraminifera‐based biozones identified include the Globigerina-Turborotalia cerroazulensis-Hantkenina Zone and Nummulites vascus-Nummulites fichteli Zone, both of Rupelian age, the Archaias asmaricus-Archaias hensoni-Miogypsinoides complanatus Zone of Chattian age and the 'Indeterminate' Zone of Aquitanian age. The vertical sedimentary evolution of the formation exhibits a progressive shallowing of the facies belts and thus the succession is interpreted as a high‐rank low‐order regressive systems tract. This long‐lasting Rupelian-Aquitanian regressive event is in accordance with accepted global long‐term eustatic curves. Accordingly, long‐term eustatic trends would have been a factor controlling accommodation during the deposition of the Asmari Formation studied in the western Fars sub‐basin

Lower Cretaceous (Hauterivian-Albian) ammonite biostratigraphy in the Maestrat Basin (E Spain)

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Lower Aptian ammonite and carbon isotope stratigraphy in the eastern Prebetic Domain (Betic Cordillera, southeastern Spain)

Major global palaeobiologic and palaeoenvironmental changes occurred during the Early Aptian. Precise dating and timing of the different events is crucial to determine possible cause-effect relationships between them. In this regard, the combination of biostratigraphic and chemostratigraphic data can provide a very useful tool for time control. So far attempts to correlate the Lower Aptian carbon isotope record and the ammonite zonation yielded contradictory conclusions. In this paper, we present the results of an integrated analysis of the ammonite stratigraphic distribution and highresolution carbon isotope profiles from Lower Aptian sections of the eastern Prebetic Domain (Betic Cordillera, southeastern Spain). We recognized, in ascending order, the Deshayesites oglanlensis, Deshayesites forbesi, Deshayesites deshayesi, and Dufrenoyia furcata Zones. This succession is the same as that recently identified in the eastern Iberian Chain, and it closely correlates with both standard Mediterranean and Boreal zonations. The carbon isotope record displays the trends globally recognized for the Early Aptian, with two long positive shifts separated by a pronounced negative excursion. Calibration of this isotopic record with the ammonite zonation shows that the age of OAE 1a, which corresponds to the negative excursion and subsequent positive shift, is constrained to the middle/upper part of the Deshayesites forbesi Zone

Lower Cretaceous (Hauterivian-Albian) ammonite biostratigraphy in the Maestrat Basin (E Spain)

A review of the stratigraphic distribution of ammonoid species in the Lower Cretaceous (Hauterivian-Albian) of the Maestrat Basin (E Spain) was carried out. The specimens were mainly collected in the field by us and are stored in university or museum collections. Speci­mens from private collections and figured in the literature were also studied. We recognized 73 species that are distributed, in accordance with the latest version of the standard Mediterranean ammonite zonation for the Lower Cretaceous, in 14 ammonite zones: Acanthodiscus radiatus, Crioceratites loryi, Lyticoceras nodosoplicatum (Lower Hauterivian); Pseudothurmannia ohmi (Upper Hauterivian); Imerites giraudi (Upper Barremian); Deshayesites oglanlensis, Deshayesites forbesi, Deshayesites deshayesi, Dufrenoyia furcata (Lower Aptian); Epicheloniceras martini, Parahoplites melchioris, Acanthohoplites nolani (Upper Aptian); Leymeriella tardefurcata and Douvilleiceras mammillatum (Lower Albian). The recognition of these biozones allows a precise age calibration of the Maestrat Basin’s lithostatigraphic units that contain ammonoids as well as an associated indirect age calibration of the formations without ammonoids. Consequently, this report provides an updated, comprehensive and precise biostratigraphic framework, which aims to become a reference for the analysis of the Lower Cretaceous strata of the Maestrat Basin. The results are also relevant for the analysis of coeval ammonite-bearing sedimentary successions found in other Tethyan basins.En este trabajo se ha realizado una revisión detallada de la distribución estratigráfica de las especies de ammonoideos del Cretácico infe­rior de la Cuenca del Maestrazgo (Este de España). Los ejemplares recolectados, principalmente por los autores, han sido depositados en co­lecciones universitarias y museísticas. Además hemos estudiado los ejemplares de colecciones privadas y figurados en la literatura. Hemos reconocido 73 especies que se distribuyen, siguiendo la última versión de la biozonación de ammonites mediterránea estándar del Cretácico inferior, en 14 zonas de ammonoideos: Acanthodiscus radiatus, Crioceratites loryi, Lyticoceras nodosoplicatum (Hauteriviense inferior); Pseudothurmannia ohmi (Hauteriviense superior); Imerites giraudi (Barremiense superior); Deshayesites oglanlensis, Deshayesites forbesi, Deshayesites deshayesi, Dufrenoyia furcata (Aptiense inferior); Epicheloniceras martini, Parahoplites melchioris, Acanthohoplites nolani (Aptiense superior); Leymeriella tardefurcata y Douvilleiceras mammillatum (Albiense inferior). El reconocimiento de estas biozonas permite precisar la edad de las unidades litoestratigráficas que contienen ammonites y también una calibración indirecta de las formaciones que no contienen ammonites. En consecuencia este trabajo proporciona un marco bioestratigráfico actualizado, exhaustivo y preciso que pretende ser una referencia para el análisis estratigráfico del Cretácico inferior de la Cuenca del Maestrazgo. Los resultados obtenidos son también relevantes para el análisis de las sucesiones sedimentarias coetáneas con ammonites existentes en otras cuencas de Tetis

Lower Cretaceous (Hauterivian-Albian) ammonite biostratigraphy in the Maestrat Basin (E Spain)

A review of the stratigraphic distribution of ammonoid species in the Lower Cretaceous (Hauterivian-Albian) of the Maestrat Basin (E Spain) was carried out. The specimens were mainly collected in the field by us and are stored in university or museum collections. Specimens from private collections and figured in the literature were also studied. We recognized 73 species that are distributed, in accordance with the latest version of the standard Mediterranean ammonite zonation for the Lower Cretaceous, in 14 ammonite zones: Acanthodiscus radiatus, Crioceratites loryi, Lyticoceras nodosoplicatum (Lower Hauterivian); Pseudothurmannia ohmi (Upper Hauterivian); Imerites giraudi (Upper Barremian); Deshayesites oglanlensis, Deshayesites forbesi, Deshayesites deshayesi, Dufrenoyia furcata (Lower Aptian); Epicheloniceras martini, Parahoplites melchioris, Acanthohoplites nolani (Upper Aptian); Leymeriella tardefurcata and Douvilleiceras mammillatum (Lower Albian). The recognition of these biozones allows a precise age calibration of the Maestrat Basin's lithostatigraphic units that contain ammonoids as well as an associated indirect age calibration of the formations without ammonoids. Consequently, this report provides an updated, comprehensive and precise biostratigraphic framework, which aims to become a reference for the analysis of the Lower Cretaceous strata of the Maestrat Basin. The results are also relevant for the analysis of coeval ammonite-bearing sedimentary successions found in other Tethyan basins.En este trabajo se ha realizado una revisión detallada de la distribución estratigráfica de las especies de ammonoideos del Cretácico infe-rior de la Cuenca del Maestrazgo (Este de España). Los ejemplares recolectados, principalmente por los autores, han sido depositados en co-lecciones universitarias y museísticas. Además hemos estudiado los ejemplares de colecciones privadas y figurados en la literatura. Hemos reconocido 73 especies que se distribuyen, siguiendo la última versión de la biozonación de ammonites mediterránea estándar del Cretácico inferior, en 14 zonas de ammonoideos: Acanthodiscus radiatus, Crioceratites loryi, Lyticoceras nodosoplicatum (Hauteriviense inferior); Pseudothurmannia ohmi (Hauteriviense superior); Imerites giraudi (Barremiense superior); Deshayesites oglanlensis, Deshayesites forbesi, Deshayesites deshayesi, Dufrenoyia furcata (Aptiense inferior); Epicheloniceras martini, Parahoplites melchioris, Acanthohoplites nolani(Aptiense superior); Leymeriella tardefurcata y Douvilleiceras mammillatum (Albiense inferior). El reconocimiento de estas biozonas permite precisar la edad de las unidades litoestratigráficas que contienen ammonites y también una calibración indirecta de las formaciones que no contienen ammonites. En consecuencia este trabajo proporciona un marco bioestratigráfico actualizado, exhaustivo y preciso que pretende ser una referencia para el análisis estratigráfico del Cretácico inferior de la Cuenca del Maestrazgo. Los resultados obtenidos son también relevantes para el análisis de las sucesiones sedimentarias coetáneas con ammonites existentes en otras cuencas de Tetis

High School Research Work and Geology dissemination: FORCES Project (UB)

X Congreso Geológico de España, 5-7 Julio 2021, Vitoria - GasteizEl Trabajo de Investigación de Bachillerato es una de las herramientas de divulgación y enseñanza de las Ciencias de la Tierra para alumnos preuniversitarios interesados en esta ciencia. La potenciación desde la Universidad hacia los centros educativos de Enseñanza Secundaria de la transferencia del conocimiento científico en el ámbito de la Geología, así como de otras ciencias, es el eje principal que se presenta en el Proyecto FORCES (Foment de la Recerca en els Centres de Secundària; http:// www.ub.edu/cere/forces/). Desde el Instituto de Desarrollo Profesional de la Universitat de Barcelona (UB) se han creado puentes entre facultades de la UB y dichos centros educativos, presentándose el caso de la Facultat de Ciències de la Terra. En FORCES se facilitan las herramientas para vincular el Trabajo de Investigación obligatorio de Bachillerato; el estudiante cuenta con el apoyo de su tutor y con el seguimiento de uno o varios profesores-investigadores del ámbito universitario. Ello amplia el marco de trabajo del alumno y le ofrece focos de interés no disponibles en los centros de Educación Secundaria, abriendo la posibilidad de colaboraciones científicas con el grupo investigador y disponer de sus herramientas, conocimientos e instrumental. Unir a la docencia universitaria la experiencia del contacto con futuros estudiantes enriquece la visión del profesorado, al situarlo en el punto de vista del estudiante de bachillerato, facilitando la comunicación de conocimientos e incorporando nuevas metodologías didácticas. Los temas geológicos tratados son amplios, teniendo como eje común la visión geológica de procesos cotidianos o próximos al alumno de Bachillerato.The High School Research Work is one of the tools of dissemination and teaching of Earth Sciences to pre-university students. The strengthening from the University to Secondary School of the transfer of scientific knowledge in the field of Geology, as well as other sciences, is the aim of the FORCES Project (Promotion of Research in High Schools; http://www.ub.edu/cere/ forces/). The Professional Development Institute (IDP-ICE) of the University of Barcelona (UB) has forged close ties between these educational centers and the different faculties of the UB, including the Faculty of Earth Sciences. FORCES provides the necessary tools to link the compulsory Research Work of the Baccalaureate students, so that the student not only has the support of his advisor, but also the follow-up of one or several professors and/or researchers. This broadens the student’s work frame and helps her/him focusing on possible areas not achievable in the context of Secondary School centers, such as establishing scientific collaborations with university research groups and thus using their tools, knowledge and analytical instruments. On the other hand, meeting prospective students enriches the professors’ vision by placing it in the mind of the High School student, improving the communication of knowledge in a more meaningful way and incorporating new teaching methodologies. Geological topics addressed are broad, having as a common thread the geological vision of everyday processes or scientific issues close to the Baccalaureate student’s daily life

Deep incision in an Aptian carbonate succession indicates major sea-level fall in the Cretaceous

Long-term relative sea-level cycles (0 5 to 6 Myr) have yet to be fully understood for the Cretaceous. During the Aptian, in the northern Maestrat Basin (Eastern Iberian Peninsula), fault-controlled subsidence created depositional space, but eustasy governed changes in depositional trends. Relative sea-level history was reconstructed by sequence stratigraphic analysis. Two forced regressive stages of relative sea-level were recognized within three depositional sequences. The first stage is late Early Aptian age (intra Dufrenoyia furcata Zone) and is characterized by foreshore to upper shoreface sedimentary wedges, which occur detached from a highstand carbonate platform, and were deposited above basin marls. The amplitude of relative sea-level drop was in the order of tens of metres, with a duration of 2 km wide and cut 115 m down into the underlying Aptian succession. With the subsequent transgression, the incision was back-filled with peritidal to shallow subtidal deposits. The changes in depositional trends, lithofacies evolution and geometric relation of the stratigraphic units characterized are similar to those observed in coeval rocks within the Maestrat Basin, as well as in other correlative basins elsewhere. The pace and magnitude of the two relative sea-level drops identified fall within the glacio-eustatic domain. In the Maestrat Basin, terrestrial palynological studies provide evidence that the late Early and Late Aptian climate was cooler than the earliest part of the Early Aptian and the Albian Stage, which were characterized by warmer environmental conditions. The outcrops documented here are significant because they preserve the results of Aptian long-term sea-level trends that are often only recognizable on larger scales (i.e. seismic) such as for the Arabian Plate

Climatic evolution across oceanic anoxic event 1a derived from terrestrial palynology and clay minerals (Maestrat Basin, Spain)

Studies dealing with the response of the continental biosphere to the environmental per- turbations associated with Cretaceous oceanic anoxic events (OAEs) are comparatively rare. Here, a quantitative spore-pollen record combined with clay mineral data is presented, which covers the entire early Aptian OAE 1a interval (Forcall Formation, Maestrat basin, east Spain). The well-expressed OAE 1a carbon-isotope anomaly is paralleled by changes in the clay mineral assemblage and by a stepwise decline in the normalized frequency of Classopollis pollen (produced by xerophytic Cheirolepidiaceae) with lowest contents occurring during the positive δ13C shift. In contrast, Araucariacites and Inaper- turopollenites pollen show a pronounced increase in relative abundance from low background values to become a significant component of the palynological assemblage during the Classopollis minimum. The observed changes in clay minerals and pollen distribution patterns are interpreted to reflect a major change in the composition of the hinterland vegetation of the Maestrat Basin, most probably due to short-lived but pronounced climatic cooling and changes in humidity. Temperature anomalies driven by organic carbon burial and associated CO2 decline have been postulated for all major Mesozoic OAEs. The palynomorph record from the Iberian Maestrat basins indicates that the climax of this cooling episode was significantly delayed in comparison to the end of organic carbon-rich deposition in the world oceans