noticias-a

New insights into the Barremian–lower Aptian calcareous nannofossils of the Mediterranean Tethys: chronostratigraphic and paleobiogeographic implications Aguado, R., Company, M., O'Dogherty, L., Sandoval, J., Martinez, M., 2022. Marine Micropaleontology 173, 102114. Open Access. https://doi.org/10.1016/j.marmicro.2022.102114 Abstract: A detailed study of calcareous nannofossil assemblages from twelve uppermost lower Barremian–lower Aptian sections in the Subbetic Domain of the Betic Cordillera was performed. Seven new nannofossil species (Crucibiscutum bastetanum, Crucibiscutum gracile, Chiastozygus lamprostauros, Cyclagelosphaera platyaspis, Lithraphidites aichmoides, Lithraphidites pugio, and Rhagodiscus sicutclipeus) are described, one species is emended (Lithraphidites magnus) and the taxonomic concept of the marker species Hayesites irregularis is discussed and clarified. The detailed stratigraphic range of new species, together with those of other relevant taxa, are determined and correlated to standard ammonite biostratigraphy. Age estimates of biostratigraphically relevant calcareous nannofossil biohorizons are calculated using astrochronologically tuned cyclostratigraphic data. Five new calcareous nannofossil subzones are proposed which enhance upper Barremian biostratigraphic resolution at a regional scale and are directly correlated with respect to the standard Tethyan ammonite zonation. Two of the new species described here are used as biostratigraphic markers for the newly proposed subzones. The duration of each subzone is also provided through astrochronological calibration. This study allows the refinement of the calcareous nannofossil zonation for the Mediterranean–Atlantic province of the Tethyan Realm. The implications of these new results are discussed regarding the extant definition and use of the Barremian/Aptian boundary. The morpho-evolutionary trends of selected nannofossil groups are reviewed in relation to the latest Barremian–Aptian paleogeographic changes, showing these were a prominent factor controlling calcareous nannoplankton evolution and biogeographical distribution in the west European-Atlantic region.

30/11/2021: Field sampling of sections Bco. de Cavila 2, Río Argos 6 y Arroyo de Gilico. 04/12/2021: Field sampling in La Frotera section. 20/01/2022: End of calcareous nannofossil quantitative study of smear-slides from the TE interval of the Bco. Cavila2 (high- resolution) and Cortijo del Hielo (mid-resolution) sections. 03/02/2022: End of processing (crushing and grinding) of samples for geochemical analytics (δ 13 Ccarb, δ 18 Ocarb, δ 13 Corg, and ICP-mass) from Bco. Cavila 2, Río Argos 6, La Frontera and Arroyo de Gilico sections. 11/02/2022: Field sampling in Carbonero section. 18/03/2022: End of calcareous nannofossil quantitative study of smear-slides from the MBE interval of the Arroyo de Gilico section (high-resolution). 29/03/2022: Field sampling in Bco. Azadillas section. 01/04/2022: ICP results and preliminary biomarker data were obtained for Río Argos 6 section. 08/04/2022: End of calcareous nannofossil quantitative study of smear-slides from the TE interval of the La Frontera section. 26/04/2022: ICP results and preliminary biomarker data were obtained for Bco. Cavila2 and Arroyo de Gilico sections. 19/05/2022: Field sampling of Cjo. del Hielo section (high-resolution). 17/06/2022: End of calcareous nannofossil quantitative study of smear-slides from the TE interval of the Río Argos 6 section (high-resolution). 17/06/2022: δ 13 Ccarb and δ 18 Ocarb results were obtained for Bco. Cavila2 and Río Argos 6 sections. 21/06/2022: ICP results (trace-elements) were obtained for Carbonero section. 02/07/2022: δ 13 Corg results were obtained for Río Argos 6 section. 05/07/2022: Carbonate content results were completed for La Frontera, Bco. Azadillas, Río Argos-6 and Cortijo del Hielo (low- resolution) sections. 08/07/2022: End of processing (crushing and grinding) of samples for geochemical analytics (δ 13 Ccarb, δ 18 Ocarb, ICP-mass and TOC) and CaCO 3 content from Cortijo del Hielo section (high-resolution). 13/07/2022: Posters and presentations for 11th International Cretaceous Symposium, 12th International Symposium Geochemistry of the Earth’s Surface, and 21th International Sedimentological Congress were composed. 24/07/2022: Attendance and presentation of a scientific communitation to 12th International Symposium Geochemistry of the Earth’s Surface, Zurich, Switzerland. 28/07/2022: ICP results (trace elements) were obtained for Cortijo del Hielo section and La Frontera sections. 22/08/2022: Attendance and presentation of a scientific communitation to 21th International Sedimentological Congress, Beijing, China. 22/08/2022: Attendance and presentation of scientific communitations to 11th International Cretaceous Symposium, Warsaw, Poland. 09/09/2022: End of processing (crushing and grinding) of samples from Cortijo del Hielo section for determinig carbonate content (high-resolution). 16/09/2022: TOC results were obtained for Río Argos 6 and Carbonero sections 26/09/2022: Oral presentation and posters for XXXVII Jornadas de Paleontología were composed. 29/09/2022: Additional carbonate content results were obtained for Bco. Cavila 2, Arroyo de Gilico and Carbonero sections. 05/10/2022: Attendance and presentation of scientific communitations to XXXVII Jornadas de Paleontología, Cuenca, Spain. 21/10/2022: Field sampling at Caravaca. 28/10/2022: ICP results (majoritary elements) were obtained for Cortijo del Hielo and La Frontera sections. 31/10/2022: ICP results (majoritary elements) were obtained for Carbonero section. 22/11/2022: Field sampling of l'Alcoraia section. 30/11/2022: End of calcareous nannofossil quantitative study of smear-slides from the TE interval of the Cortijo del Hielo section (high-resolution). 20/12/2022: TOC results were obtained for Cortijo del Hielo, La Frontera y Bco. Azadillas sections. 21/12/2022: δ 13 Ccarb and δ 18 Ocarb results were obtained for Cortijo del Hielo section.

Orbital control of the anoxic events in the Hauterivian and Barremian stages. Martinez, M., Aguado, R., Company, M., Sandoval., J., O'Dogherty, L. 27e Réunion des Sciences de la Terre. Lyon 1-5 Nov 2021. Abstracts, p. 622. First record of a carbon cycle perturbation during the late Barremian: Multiproxy evidence for environmental change (Caravaca, Spain). Sequero, C., Aguado, R., Quijano., M.L., de Gea, G.A., Froehner, S., Company, M., O'Dogherty, L., Castro, J.M. 12th International Symposium Geochemistry of the Earth’s Surface, Zurich 24-29 Jul 2022. https://doi.org/10.5281/zenodo.6813090 . Complex environmental perturbations related to the early Aptian OAE 1a – insights from a pelagic succession from the western Tethys (Subbetic Zone, SE Spain). Sequero, C., Castro, J.M., Quijano., M.L., Aguado, R., de Gea, G.A., Naafs, B.D.A., Lowson, C., Pancost, R.D. 21th International Sedimentological Congress, Beijing 22-26 Aug 2022. Abstracts book, p. 174. Geochemical and calcareous nannofossil evidences of two late Barremian episodes of environmental change (SE Spain). Aguado, R., Company, M., Castro, J.M., de Gea, G.A., O'Dogherty, L., Sandoval, J., Quijano, M.L., Martinez, M., Froehner, S., Sequero, C. 11th International Cretaceous Symposium, Warsaw 22-26 Aug 2022. Abstract volume, p. 109–110. Synchronizing the timing of carbon cycle, volcanism and the pacing of the Earth’s orbit during the Early Cretaceous. Martinez, M., Aguirre-Urreta, M.B., Dera, G., Lescano, M., Omarini, J., Tunik, M., O'Dogherty, L., Aguado, R., Company, M., Bodin, S. 11th International Cretaceous Symposium, Warsaw 22-26 Aug 2022. Abstract volume, p. 263–264. Registro de dos episodios de cambio ambiental acelerado en el Barremiense superior: evidencias basadas en estratigrafía isotópica y nanofósiles calcáreos. [Record of two episodes of accelerated environmental change in the late Barremian: isotope stratigraphy and calcareous nannofossil evidences], Aguado, R., Company, M., Sandoval, J., O'Dogherty, L., Martinez, M., Castro, J.M., de Gea, G.A., 2022. in: Blanco, F., Blanco-Moreno, C., et al. (Eds.), Libro de Resúmenes de las XXXVII Jornadas SEP y V Congreso Ibérico de Paleontología. Palaeontological publications, 2, Cuenca, España, p. 25. Respuesta biótica y geoquímica al evento hipertermal del Aptiense inferior (OAE1a). Sondeo de Cau (Prebético de Alicante, España). [Geochemical and biotic response to the Early Aptian hyperthermal event (OAE 1a). The Cau Core (Prebetic of Alicante, Spain)]. de Gea, G.A., Castro, J.M., Aguado, R., Ruiz-Ortiz, P.A., Nieto, L.M., Quijano, M.L., Sequero, C., Froehner, S., 2022. in: Blanco, F., Blanco-Moreno, C., et al. (Eds.), Libro de Resúmenes de las XXXVII Jornadas SEP y V Congreso Ibérico de Paleontología. Palaeontological publications, 2, Cuenca, España, p. 60.

Synchrony of carbon cycle fluctuations, volcanism and orbital forcing during the Early Cretaceous Martinez, M., Aguirre-Urreta, B., Dera, G., Lescano, M., Omarini, J., Tunik, M., O'Dogherty, L., Aguado, R., Company, M., Bodin, S. Accepted for publication in the journal Earh-Science Reviews. Abstract: Episodes of Environmental Change (EECs) were times of accelerated hydrological cycle that punctuated the Early Cretaceous. Uncertainties in the geologic time scales however preclude full understanding of the onset, unfolding, and termination of EECs. Here, we reanalyze the hemipelagic sedimentary series from France and Spain from the Valanginian to the Barremian to provide a comprehensive and accurate time scale of the Valanginian–Barremian interval based on the stable 405-kyr eccentricity cycle. According to our astrochonologic framework, the Weissert Event started 134.56 ± 0.19 Ma, in perfect synchronicity with the peak of volcanic activity of the Paraná-Etendeka Large Igneous Province. On average, EECs show a pacing of 2.40 Myr from the Valanginian to the Barremian, in phase with detrital supply and carbon isotope variations from marine carbonates. Long eccentricity cycles were hence key parameters in the regulation of climate and carbon cycles in the Early Cretaceous through changes in the detrital and nutrient supply, oceanic fertilization, organic carbon storage and global sea level. A long obliquity forcing, at 1.2 Myr, is also observed through the studied interval in both the detrital and carbon- isotope ratios series, allowing the identification of long isotopic stages in the Early Cretaceous. Our study highlights a positive correlation between continental runoff and sea-level change, suggesting that glacio-eustasy, and not aquifer-eustasy, was the main driver of global sea level fluctuations during the Early Cretaceous. We also demonstrate that the humid peak related to the Weissert Event is driven by the pacing of the long orbital cycles despite the emplacement of the Paraná-Etendeka province. Nevertheless, in comparison to other EECs of the Valanginian–Barremian, the Weissert Event appears as a singularly long event with stronger impact on climate and marine ecosystems compared to other EECs. We posit that this is a consequence of the concomitant effect of the emplacement of the Paraná-Etendeka province and the long orbital cycles.

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