Departamento de Geología
URI permanente para esta comunidadhttps://hdl.handle.net/10953/34
En esta Comunidad se recogen los documentos generados por el Departamento de Geología y que cumplen los requisitos de Copyright para su difusión en acceso abierto.
Examinar
Examinando Departamento de Geología por Autor "Castro-Jiménez, José Manuel"
Mostrando 1 - 2 de 2
- Resultados por página
- Opciones de ordenación
Ítem High-resolution C-Isotope, TOC and biostratigraphic records of OAE1a (Aptian) from an expanded hemipelagi cored succession, Western Tethys: a new stratigraphic reference for global correlation and paleoenvironmental reconstruction(Wiley, 2021-02-08) Castro-Jiménez, José Manuel; Ruiz-Ortiz, Pedro A.; de Gea, Ginés A.; Aguado-Merlo, Roque; Jarvis, Ian; Weissert, Helmut; Molina-López, José Manuel; Nieto-Albert, Luis Miguel; Pancost, Richard D.; Quijano, Maria Luisa; Reolid, Matías; Skelton, Peter William; López-Rodríguez, Carmina; Martínez-Rodríguez, RafaelA high-resolution carbonate C-isotope stratigraphy for the Aptian is presented for the Cau core (Spain). The biostratigraphically calibrated C-isotope stratigraphy of the core is used to refine the previously defined C-isotope segments of the Aptian. Thirteen C-isotope segments have been identified and correlated, and further subdivisions are presented. Correlation with other sections worldwide demonstrates the robustness of the C-isotope stratigraphy of the Cau core. The studied succession includes a continuous record of the early Aptian Oceanic Anoxic Event (OAE 1a). Its onset has been studied at an ultrahigh-resolution scale (0.2–0.5 kyr spacing), revealing a succession of sharp δ13Ccarb negative spikes, interpreted as a record of pulses of volcanism and methane emissions. The largest spike was rapid (<10 kyr) and marks the base of OAE 1a, which occurs within a longer-term falling δ13Ccarb trend. The C-isotope profile across OAE 1a perfectly records the negative (C3/Ap3), positive (C4/Ap4), steady (C5/Ap5), and positive (C6/Ap6) segments that were defined from Cismon (Italy) and subsequently identified worldwide. The Ap7 to Ap14 segments record a C-isotope negative excursion, coupled with high TOC contents, probably related to regional paleogeography. The links with global environmental changes, episodes of widespread deposition of organic matter, and ultimately to major volcanic episodes are discussed. We propose the Cau core as a new reference section for the Aptian, and specifically for OAE 1a, based on its expanded and well-preserved sedimentary, geochemical and biotic archives, which provide further insights into the environmental and biotic changes that occurred during this time interval.Ítem Integrated cyclostratigraphy of the Cau core (SE Spain) - A timescale for climate change during the early Aptian Anoxic Event (OAE 1a) and the late Aptian(Elsevier, 2024-01-16) Martínez-Rodríguez, Rafael; Batenburg, Sietske J.; Castro-Jiménez, José Manuel; de-Gea, Ginés; Nieto-Albert, Luis Miguel; Ruiz-Ortiz, Pedro Alejandro; Robinson, StuartWe report a cyclostratigraphic study performed on the Cau core (Spain), which is considered an Aptian stratigraphic reference for global correlation and paleoenvironmental reconstruction. This investigation presents an astronomical timescale for the Aptian from the Ap2a to Ap14 carbon-isotope stages. Based on the evaluation of a multiproxy dataset from the Cau core, we recalibrate the age and duration of different biozones, bioevents, chemostratigraphic substages and horizons from the early and late Aptian, with special focus on the Selli Event, providing a new astronomical framework for Aptian climate. From the recognition of 14 long-eccentricity cycles, we propose a time span of 5.67 Ma from C-isotope segments Ap2a to the top of Ap14, and ages of 120.82 Ma for the onset of the nannoconid crisis, and 120.20 Ma for the onset of oceanic anoxic event (OAE) 1a. Calculations yield a duration of 1.47 Ma for OAE 1a. We estimate the age for the onset of the main non-radiogenic phase of the Os isotopes at 120.08 Ma, 120 ka after the onset of OAE 1a. The high-resolution data from the Cau core provide further insights in the temporal constraints of the OAE 1a and other Aptian paleoclimatic events. The onset of the main non-radiogenic excursion in Os isotopes occurring 120 ka after the onset of OAE 1a reinforces the theory of rapid destabilization of methane hydrates as the trigger of the anoxic event, that preceded the onset of large-scale volcanism.