Synchronizing the timing of anoxia, volcanism and the pacing of the Earth’s orbit in the Early Cretaceous

Recurrent acceleration of the hydrolysing cycle, so-called Episodes of Environmental Changes, occur in the Early Cretaceous. As the geologic time scale show large uncertainties, the pacing and the chronological relationship of these events remain obscure. We present here new radio-astrochronologic data from the Neuquén Basin (Argentina) anchored to the Tethyan realm. The new time sale of the Valanginian-Hauterivian provides ages of ammonite zones with an uncertainty of ± 0.2 myr and provides much precise age of the start of the Weissert Event. The age of the start of the Weissert Event is at 134.5 ± 0.2 myr, which is exactly synchronous with the main phase of the Paraná-Etendeka large igneous province activity. Most recent duration and age estimates from the Berriasian to the Barremian are reviewed and differ from the Geologic Time Scale 2016 by several million of years. Thanks to this new time scale, belemnite δ13C are reviewed and show a strong pacing with a period of 2.4 myr, which correspond to the long-eccentricity cycle. Higher amplitudes of the 2.4-myr cycle are observed at time of large igneous province emplacement, which may be due to accelerated hydrolysis cycle following CO2 input to the atmosphere from the volcanic activity.Fil: Martinez, Mathieu. Universite de Rennes I; FranciaFil: Aguirre Urreta, María Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Lescano, Marina Aurora. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Omarini, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Tunik, Maisa Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Frederichs, Thomas. Universitat Bremen; AlemaniaFil: Nickl, Anna-Leah. Universitat Bremen; AlemaniaFil: Pälike, Heiko. Universitat Bremen; AlemaniaEGU General Assembly 2019VienaAustriaEuropean Geosciences Unio

Assessing orbital vs. volcanic control on carbon cycle during the Early Cretaceous

The interval from the Valanginian to the Barremian stages (137?121 Ma; Early Cretaceous) ispunctuated by several episodes of environmental changes, accompanied by shifts in weatheringintensity on the continents and changes in the Tethyan neritic carbonate production. Wesynthetize here the astrochronology of two recent studies performed in the Neuquén basin,Vocontian Basin and Subbetic Domain (Aguirre-Urreta et al., 2019; Martinez et al., 2020), anchoredto CA-ID-TIMS U-Pb ages, which conclusions have been included in the Geologic Time Scale 2020(Gale et al, in press). We applied this time scale to a compilation of carbon-isotope ratio frombelemnites and proxies of detrital supply in the Tethyan area (Vocontian Basin and SubbeticDomain). From this compilation, we show that the episodes of environmental changes are pacedby a 2.4-Myr cycle and, with a lower amplitude, a 1.2-Myr cycle. In addition, the new time scaleshows the synchronicity between the Weissert Event and the Parana-Etendeka Large IgneousProvince. In the series of carbon-isotope ratios measured on belemnite rostra, the amplitude ofthe 2.4-Myr cycle is twice higher during the Valanginian than in the Late Barremian and threetimes higher than in the Hauterivian and Early Barremian, suggesting that the activity of theParana-Etendeka Large Igneous Province amplified the initial orbital forcing to trigger theenvironmental changes observed during the Mid-Valanginian.Fil: Martinez, M.. Géosciences Rennes; FranciaFil: Aguirre Urreta, María Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Lescano, Marina Aurora. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Dera, G.. Université Paul Sabatier; FranciaFil: Omarini, Julieta. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; ArgentinaFil: Tunik, Maisa Andrea. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Frederichs, Tomas. Universitat Bremen; AlemaniaFil: Palike, Heiko. Université Paul Sabatier; FranciaFil: O'Dogherty, Luis. Universidad de Cádiz; EspañaFil: Aguado, Roque. Universidad de Jaén; EspañaFil: Company, Miguel. Universidad de Granada; EspañaFil: Sandoval, Jose. Universidad de Granada; EspañaEGU General Assembly 2021AlemaniaEuropean Geosciences Unio

El Cretácico temprano de la cuenca Neuquina, centro-oeste de Argentina: nuevos datos bioestratigráficos, cicloestratigráficos y geocronológicos

Los pisos estándar del Cretácico Inferior están basados en secciones estratigráficas ubicadas en el Tethys occidental y están definidos principalmente sobre la base de bioestratigrafía de amonites y de nanofósiles calcáreos, los que han sido calibrados con la secuencia M de crones de polaridad magnética. Sin embargo, la casi falta de edades radiométricas de alta resolución ha impedido la construcción de una escala de tiempo geológica precisa para el intervalo en cuestión. Esta situación se ve claramente reflejada en la Tabla Cronoestratigráfica Internacional publicada por la Comisión Internacional de Estratigrafía (http://www.stratigraphy.org/ICSchart/) donde todas las edades absolutas de los límites desde la base del Berriasiano (~ 145 Ma) hasta la base del Albiano (~ 100 Ma), o sea todo el Cretácico inferior, son aproximadas. La cuenca Neuquina en el centro-oeste de Argentina es un excelente sitio para realizar estudios bioestratigráficos, cicloestratigráficos y radioisotópicos en parte de este intervalo, dados sus completos afloramientos donde se registran abundantes mega, microfósiles y nanofósiles a lo que se agrega la presencia de tobas de caída intercaladas en las espesas sucesiones sedimentarias. Aquí nos concentramos en la Formación Agrio, unidad compuesta de rocas siliciclásticas y carbonatadas marinas e integrada por tres miembros (Pilmatué, Avilé y Aguada de la Mula). La formación se ha estudiado durante más de 20 años y su contenido rico en amonites y nanofósiles calcáreos permite datarla en el intervalo entre el Valanginiano inferior alto y el Hauteriviano superior. Por lo tanto, la Formación Agrio representa una oportunidad única para producir una escala astrocronológica anclada en cuatro edades CA-ID-TIMS U-Pb, calibrar las zonas/subzonas de amonites andinos y vincular esta escala de tiempo absoluta a la  cronoestratigrafía estándar del área occidental de Tethys. Los resultados obtenidos permiten no solo alargar considerablemente la duración del Hauteriviano sino también modificar sus límites inferior y superior. Por lo tanto, nuestros nuevos datos refuerzan la necesidad de modificar sustancialmente las edades absolutas actualmente aceptadas para este importante intervalo en la historia del Mesozoico.Fil: Aguirre Urreta, María Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Lescano, Marina Aurora. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Martinez, Mathieu. Universite de Rennes I; FranciaFil: Tunik, Maisa Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Concheyro, Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Omarini, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Ramos, Victor Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaXV Congreso Geologico ChilenoConcepciónChileUniversidad de ConcepciónColegio de Geólogos de ChileSociedad Geológica de Chil

Synchronizing the timing of anoxia, volcanism and the pacing of the Earth’s orbit in the Early Cretaceous

International audienceRecurrent acceleration of the hydrolysing cycle, so-called Episodes of Environmental Changes, occur in the EarlyCretaceous. As the geologic time scale show large uncertainties, the pacing and the chronological relationshipof these events remain still obscure. We present here new radio-astrochronologic data from the Neuquén Basin(Argentina) anchored to the Tethyan realm. The new time scale of the Valanginian-Hauterivian provides ages ofammonite zones with an uncertainty of 0.2 myr and provides a much more precise age for the start of theWeissert Event. The age of the start of the Weissert Event is at 134.5 0.2 Ma, which is exactly synchronouswith the main phase of the Paraná-Etendeka large igneous province activity. Most recent estimates for duration andage estimates from the Berriasian to the Barremian are compiled and differ from the Geological Time Scale 2016by several million years. As a result of this new time scale, belemnite 13C are recalibrated in age and show astrong pacing with a period of 2.4 myr, which corresponds to the long-eccentricity cycle. Higher amplitudes of the2.4-myr cycle are observed at the time of large igneous province emplacement, which may be due to acceleratedhydrolysis cycle following CO2 input to the atmosphere from the volcanic activity

Facies heterogeneity and source potential of carbonate-mudstone-dominated distal ramp deposits, Agrio Formation, Neuquén Basin, Argentina

The carbonate-mudstone-dominated Lower Cretaceous Agrio Formation is the youngest marine source rock of the hydrocarbon-prolific Neuquen Basin in Argentina, yet its facies variability and unconventional ´ hydrocarbon potential remains relatively understudied. Detailed studies of mudstone facies variability in thick, carbonate mudstone successions deposited largely below storm wave base (i.e., chalk–marl, black shale, limestone), like the Agrio Formation, are rare and instead commonly focus on biostratigraphy or organic geochemistry alone. A continuous northern section of the Agrio Formation and a southern composite section of the lower Pilmatué and middle Avilé members, totaling ~ 1,200 m of outcrop, were measured. From these measured sections, programmed pyrolysis (n = 339 samples), X-ray diffraction (XRD; n = 69), and thin sections (n = 69) were used to develop a high-resolution integrated macrofacies and microfacies scheme. The four most volumetrically abundant facies include detrital-quartz-silt-bearing fine mudstone (facies 1), radiolarian-bearing calcareous fine mudstone (facies 2), detrital-quartz-silt- and shell-bearing calcareous fine mudstone (facies 3), and calcareous wackestone (facies 4). All four facies are volumetrically dominated by carbonate mud matrix (i.e., micrite) that represents either 1) original pelagic coccolithophore deposition modified by diagenesis, 2) transported carbonate mud (i.e., bottom currents like contour currents or sediment gravity flows), or 3) a combination of both. Outcrop observations, XRD mineralogic trends, and petrographic variations in grain composition between detrital quartz silt, radiolarian and microfossil to macrofossil content (mainly benthic foraminifera and bivalves) distinguish the four mudstone facies. The facies scheme indicates distinctly more heterogeneous and current-influenced sedimentation in the downdip sub-storm wave base than previously described in the Agrio and in carbonate-dominated basinal settings in general. A depositional model is proposed for further testing that may prove valuable towards re-evaluating basinal carbonate mudstone successions worldwide. Utilizing TOC, S2, and HI value cutoffs, this study defines five discrete stratigraphic packages in the Agrio Formation that have the highest source potential, collectively totaling ~ 140 m thick. The novel integration of macrofacies and microfacies analysis, stratigraphy, and a geochemical analysis allow both depositional insights and the assessment of a potential source rock. The study adds to a growing body of literature on 1) carbonate ramp (or slope) to basinal processes and 2) facies models for organic-rich, carbonate-dominated mudstone successions that are unconventional hydrocarbon systems.Fil: Moore, Shawn A.. State University Of Utah. Energy Of Geoscience Institute; Estados UnidosFil: Birgenheier, Lauren P.. State University Of Utah. Energy Of Geoscience Institute; Estados UnidosFil: Greb, Matthias D.. State University Of Utah. Energy Of Geoscience Institute; Estados UnidosFil: Minisini, Daniel. Shell Exploration and Production; Estados Unidos. Shell Houston Technology Center; Estados UnidosFil: Tunik, Maisa Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Omarini Fernández, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentin

Essential oils from Dysphania ambrosioides and Tagetes minuta enhance the toxicity of a conventional insecticide against Alphitobius diaperinus

The darkling beetle Alphitobius diaperinus is one of the most common pests in poultry farms, with its occurrencecausing several problems including the dispersion of pathogenic microorganisms, injuries and stress in birds, aswell as structural damage to the facilities. The aim of this study was to investigate the chemical composition ofessential oils (EOs) from Dysphania ambrosioides and Tagetes minuta, and to determine their contact toxicity aloneand in combination with cypermethrin against adults of A. diaperinus. The main components of the EOs wereascaridole, p-cymene and carvacrol in D. ambrosioides oil, and dihydrotagetone, cis-ocimenone, trans-tagetoneand trans-β-ocimene in T. minuta oil. The EOs from both plants showed a high contact activity, while cypermethrinwas slightly toxic to the insect when applied alone. The toxicity of D. ambrosioides oil was six times better than that of T. minuta oil, and more than fifty times more effective than cypermethrin. When cypermethrin was applied in combination with the EOs at low concentrations, the toxicity of this insecticide increased significantly. As the EOs studied have interesting properties against A. diaperinus, their use could be considered in new strategies for pest management.Fil: Arena, Julieta Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Investigaciones Entomológicas de Córdoba; ArgentinaFil: Omarini, Alejandra Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Entre Ríos. Universidad Nacional de Entre Ríos. Centro de Investigaciones y Transferencia de Entre Ríos; ArgentinaFil: Zunino, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Peschiutta, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Defagó, María Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Investigaciones Entomológicas de Córdoba; ArgentinaFil: Zygadlo, Julio Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Synchrony of carbon cycle fluctuations, volcanism and orbital forcing during the Early Cretaceous

International audienceEpisodes 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

Astrochronology of the Agrio Formation (Neuquén Basin, Argentina): toward an intercalibration of the ammonite zones in the Early Cretaceous

Interbasinal correlations at high resolution requirethe precise definition of the chronological relationships between thebiostratigraphic markers, from a faunal province to another. In the Early Cretaceous,the Kilian Group tends to establish correlation charts between the Andean andthe Tethyan ammonite zones (Reboulet et al., 2014). Attempts to providedurations and numerical ages of the ammonite zones in the Valanginian and theHauterivian stages have been made, based on cyclostratigraphy in the Tethyanarea (Martinez et al., 2015), and on the U-Pb method on volcanic ashes in theNeuquén Basin (Aguirre-Urreta et al., 2015). Because of the scarcity of ashlayers in the Tethyan area, the durations calculated for the ammonite zonescannot be anchored on numerical ages without correlations with the Andeanseries. Conversely, the Andean series have not been dated by cyclostratigraphy.The hemipelagic sediments of the Neuquén Basin in the Upper Valanginian-Hauterivianform the Agrio Formation. This formation is composed of marl-limestonealternations, likely forced by the orbital cycles (Sagasti, 2005).We propose here the first orbital time scale ofthe Agrio Formation and its subdivisions (biozones) based on magneticsusceptibility measurements (MS). The MS measurements reflect themarl-limestone alternations, with higher values for the marls, rich iniron-bearing clay minerals than in the limestone beds. The first results ofspectral analyses tend to show a pervasive expression of the eccentricitycycles. Notably the time of deposit of the lower part of the Agrio Formation isestimated as 5.4 myr. Such a long duration is in disagreement with the currentgeological time scale (Gradstein et al., 2012), but agrees with the calibrationof the Valanginian-Hauterivian times performed in the Tethyan basins (Martinezet al., 2015).Fil: Martinez, Mathieu. Universitat Bremen; AlemaniaFil: Aguirre Urreta, María Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Lescano, Marina Aurora. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Omarini, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Tunik, Maisa Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Frederichs, Thomas. Universitat Bremen; AlemaniaFil: Nickl, A.. Universitat Bremen; AlemaniaFil: Palike, H.. Universitat Bremen; AlemaniaRéunion thématique 2016 du Groupe Français du CrétacéParisFranciaGroupe Français du Crétac

Palaeoenvironmental conditions for the preservation of organic matter during the late Hauterivian in the Neuquén Basin (Western Argentina)

International audienceThe Agua de la Mula Member of the Agrio Formation in the Neuquén Basin, comprises marine deposits accumulated in a mixed carbonate-siliciclastic outer ramp during the late Hauterivian. An innovative multi-proxy study that includes sedimentological, geochemical and paleobiological data from the El Portón section were combined in order to constrain the environmental context.Two major sedimentary cycles have been recognised (TST-HST) reflecting the position of most distal and proximal sediments in the depositional system. The distal outer ramp deposits (FA1) are predominantly characterised by carbonate-bearing mudstones, with TOC content up to 4.43 wt% TOC (average 1.62 wt%) and Type II marine-derived amorphous organic matter. The high TOC could be reflecting enhanced bioproductivity during periods of decreased salinity as mirrored by peaks of Micrantholithus, and reduced dilution by siliciclastic material in a distal setting. Conversely, the proximal outer ramp succession (FA2) shows a higher siliciclastic pattern, along with the terrestrial organic matter signal (Type II-III kerogen) and TOC content around 1 wt% (average 1.05 wt%). In this interval primary production is associated with more stable conditions and stratified water, as reflected in peaks of Nannoconus. These conditions allowed a greater diversity and high abundances of calcareous nannofossils assemblages

Synchronising the timing of carbon cycle, volcanism and pacing of the Earth’s orbit during the Early Cretaceous

The Weissert Event (mid-Valanginian), the Faraoni Event (latest Hauterivian), the mid-Barremian and Taxy events in the Barremian are referred to as Episodes of Environmental Change (EECs) (Föllmi 2012). These episodes are associated with accelerated hydrolysis cycles, increased levels of continental weathering and temperature-triggered fertilization of water masses. Other events were recognized in the Berriasian to Barremian, suggesting that these events punctuated the Early Cretaceous (Kujau et al. 2013; Charbonnier et al. 2016; Martinez 2018; Martinez et al. 2020). Uncertainties in the geological time scales, however, preclude the full understanding of the onset, unfolding and termination of EECs. Here, we analyze the amplitude modulation of precession cycles recorded in two Hauterivian sedimentary series in France and Spain to provide a comprehensive and accurate time scale of the Valanginian–Barremian interval based on the stable 405-kyr eccentricity cycle. The new time scale proposed here significantly differs from the Geologic Time Scale 2020 (GTS 2020) (Gradstein et al. 2021). According to our astrochonological framework, the Weissert Event started at 134.56±0.18 Ma, in perfect synchronicity with the peak of volcanic activity of the Paraná-Etendeka Large Igneous Province. The above-mentioned EECs are within a pacing of 2.40 myr of the detrital supply and carbon isotope variations recorded in bulk rock and belemnite rostra. Hence, long eccentricity cycles were key parameters in the regulation of climate and carbon cycles during the Early Cretaceous through changes in the detrital and nutrient supply, oceanic fertilization, organic carbon storage and global sea level. We also demonstrate that the humid peak related to the Weissert Event is driven by the pacing of the long orbital cycles, in spite of the emplacement of the Paraná-Etendeka province. Nevertheless, in comparison to other EECs of the Valanginian–Barremian, the Weissert Event appears to be a singularly long event with profound impact on climate and marine ecosystems. We posit that this is a consequence of the concomitant effect of the emplacement of the Paraná-Etendeka province and the long orbital cycles.Fil: Martinez, Mathieu. Universite de Rennes I; FranciaFil: Aguirre Urreta, María Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Dera, Guillaume. Université Paul Sabatier; FranciaFil: Lescano, Marina Aurora. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Omarini, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Tunik, Maisa Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: O’Dogherty, Luis. Universidad de Cádiz; EspañaFil: Aguado, Roque. Universidad de Jaén; EspañaFil: Company, Miguel. Universidad de Granada; EspañaFil: Bodin, Stéphane. University Aarhus; Dinamarca11th International Cretaceous SymposiumVarsoviaPoloniaUniversity of Warsaw. Faculty of Geolog