0000000000143436

AUTHOR

Mathieu Martinez

0000-0003-0741-2940

High-resolution clay mineralogy as a proxy for orbital tuning: example of the Hauterivian-Barremian transition in the Betic Cordillera (SE Spain).

11 pages; International audience; The response of clay mineral assemblages to potential orbital forcing is tested in Mesozoic hemipelagic marl- limestone rhythmites of the Río Argos section (Betic Cordillera, Southeastern Spain). Along the section, marls are pervasively enriched in kaolinite and illite, whereas limestones are enriched in smectite-rich illite/smectite mixed-layers, suggesting that marl-limestone alternations are produced by cyclic high-frequency fluctuations of continental runoff. Spectral analyses show that clay mineral assemblages evolve accordingly to precession, obliquity and eccentricity cycles. Durations of ammonite zones are assessed at 535 kyr for the Late Hauterivia…

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Carbon cycle and sea-water palaeotemperature evolution at the Middle-Late Jurassic transition, eastern Paris Basin (France).

14 pages; International audience; A very high-resolution carbon and oxygen stable isotope analysis (bulk-carbonate) of a biostratigraphically well-constrained Callovian-Oxfordian series is provided here for the first time. The homogeneity of the clayey series and the weak diagenetic alteration allow the isotopic signal variations to be considered as primary in origin. A prominent and brief negative excursion in the δ13C curve (−2‰), occurring at the start of the Middle Callovian (Jason Zone - Obductum Subzone) and correlated regionally, suggests a possible methane release. The increasing δ13C values thereafter up to the Early Oxfordian, concomitant with a warming episode, highlight the buri…

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The late Hauterivian Faraoni "Oceanic Anoxic Event" at Río Argos (southern Spain): an assessment on the level of oxygen depletion.

14 pages; International audience; An integrated study of multiple geochemical proxies (TOC, δ13Ccarb, trace metallic elements, iron speciation) on the late Hauterivian Faraoni Oceanic Anoxic Event has been performed along the hemi-pelagic section of Río Argos (south-eastern Spain) in order to better constrain the environmental perturbations linked to this event in the Subbetic domain. In the studied section, the TOC is relatively low (b0.5 wt.%) except for one sample at the base of the Faraoni horizon, where it reaches 1.5 wt.%. The δ13Ccarb signal is characterized by a minor long-term increase, primarily attributed to an enhanced organic matter burial. However, both organic and isotopic si…

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The Mid-Cenomanian Event in southeastern France: evidence from palaeontological and clay mineralogical data.

16 pages; International audience; Reconstruction of main palaeoenvironmental conditions across the Mid-Cenomanian Event (MCE I) in the hemipelagic Tethyan section of Blieux (Southeast France, Vocontian Basin) is proposed. Quantitative analyses of calcareous nannofossil, ammonoid and clay mineral assemblages have been made and compared with respect to sea level changes and the carbon cycle perturbations. The nannofossil primary productivity, as recorded by nannofossil fluxes and relative abundances of meso-eutrophic taxa, is low just below and during the MCE Ia, then slightly increases in the interval including the MCE Ib. The clay assemblages mainly consist of illite/smectite mixed-layers w…

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Integrated stratigraphy of the Oxfordian global stratotype section and point (GSSP) candidate in the Subalpine Basin (SE France).

44 pages; International audience; An integrated biostratigraphic approach, based on ammonites, calcareous nannofossils, dinoflagellates, combined with sedimentology, carbon-isotope and physical stratigraphy, is proposed for the Subalpine Basin (Thuoux and Saint-Pierre d'Argençon sections). Within the expanded marl deposits of the Terres Noires Fm., the Callovian-Oxfordian boundary is particularly well defined by ammonite taxa from different families (i.e. Cardioceratidae, Oppeliidae, Aspidoceratidae and Perisphinctidae), calcareous nannoplankton (first occurrence of large-sized Stephanolithion bigotii) and dinoflagellate cysts (first occurrence of Wanaea fimbriata). This precise biostratigr…

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Orbital chronology of the lower-middle Aptian: palaeoenvironmental implications (Serre Chaitieu section, Vocontian Basin).

4 pages; International audience; A detailed cyclostratigraphic study conducted on several proxies including spectral gamma ray, magnetic susceptibility, clay minerals, and carbonate content suggests that the return to equilibrium in the carbon cycle after the major disturbance linked with Oceanic Anoxic Event 1a occurred in about 2 Myr. The minimum duration of the D. furcata zone is estimated at 0.46 Myr and that of the E. subnodosocostatum zone at 1.45 Myr. Strengthening of the obliquity record in the furcata zone confirms the cooling that characterizes this period.

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An orbital floating time scale of the Hauterivian/Barremian GSSP from a magnetic susceptibility signal (Río Argos, Spain).

10 pages; International audience; An orbital floating time scale of the HauterivianeBarremian transition (Early Cretaceous) is proposed using high-resolution magnetic susceptibility measurements. Orbital tuning was performed on the Río Argos section (southeast Spain), the candidate for a Global boundary Stratotype Section and Point (GSSP) for the HauterivianeBarremian transition. Spectral analyses of MS variations, coupled with the frequency ratio method, allow the recognition of precession, obliquity and eccentricity frequency bands. Orbitallytuned magnetic susceptibility provides minimum durations for ammonite biozones. The durations of well-constrained ammonite zones are assessed at 0.78…

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Carbon and Oxygen Isotope Signals from the Callovian–Oxfordian in French Sedimentary Basins

3 pages; International audience; High-resolution carbon and oxygen isotope data from the Paris Basin and the Subalpine Basin (France) are available in a precise biostratigraphic framework for the Callovian-Oxfordian stages. A biostratigraphically well-constrained δ13C curve, derived from bulk carbonates in the Paris Basin and the Subalpine Basin, is provided in order to document carbon-cycle evolution and to serve as a chemostratigraphic reference for the Callovian-Oxfordian in the Tethyan domain. Sea-temperature reconstructions, using diagenetically screened belemnite and oyster data, reveal major climate perturbations at the Middle-Late Jurassic transition.

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Astrochronology of the Valanginian-Hauterivian stages (Early Cretaceous): chronological relationships between the Paraná-Etendeka large igneous province and the Weissert and the Faraoni events.

16 pages; International audience; The Geological Time Scale shows large uncertainties on durations and ages of Berriasian to Albian stages (Early Cretaceous), which impact climate and paleoceanographic reconstructions. Here, we provide a new astrochronology of the Hauterivian Stage anchored on (1) recent biostratigraphically well-constrained published radio-isotopic dates, and (2) a previously published astrochronology of the Valanginian Stage. A new duration of the Hauterivian Stage is assessed here at 5.93 ± 0.41 myr. The retained age model, anchored on a latest CA-ID-TIMS U–Pb age from a tuff level in the Hauterivian of the Neuquén Basin (Argentina), dates the base of the Valanginian Sta…

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Astrochronology of the Valanginian stage from GSSP candidates and hypostratotype.

Valanginian; Astrochronology; Gamma-ray spectrometry; Weissert event; Paraná-Etendeka; International audience; The Valanginian Stage currently displays no radiometric age, which severely hampers palaeoceanographic reconstructions for this time interval. An astrochronology of the Valanginian Stage using the stable 405-kyr eccentricity cycle was performed on biostratigraphically well-calibrated standard sections from the Vocontian Basin (southeastern France). High-resolution gamma-ray spectrometry signals were obtained from orbitally driven marl-limestone alternations from five sections in the basin, and they display the same long-term trends. The spectral analyses present the pervasive recor…

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Astronomical calibration of the Valanginian and the Hauterivian stages (lower cretaceous) : paleoclimatic and paleooceanographic implications

Orbital floating time scales are proposed for the Valanginian Stage and part of the Hauterivian Stage (Early Cretaceous). These are based on the identification of the eccentricity cycles from spectral analyses performed on high-resolution climatic proxies measured on hemipelagic marl-limestone alternations. Five reference sections were analysed in the Vocontian Basin (SE France), spanning the entire Valanginian. A duration of 5,08 myr is proposed for the Valanginian Stage from the identification of the 405-kyr eccentricity cycle. The time frame proposed, combined with available radiometric ages, shows that the mid-Valanginian 13C positive excursion (namely the Weissert Event) occurs prior …

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Water mass exchange and variations in seawater temperature in the NW Tethys during the Early Jurassic: evidence from neodymium and oxygen isotopes of fish teeth and belemnites.

10 pages; International audience; Oxygen and neodymium isotope analyses performed on biostratigraphically well-dated fish remains recovered from the Hettangian to Toarcian of the Paris Basin were used to reconstruct variations of Early Jurassic seawater temperature and to track oceanographic changes in the NW Tethys. Our results indicate a strong correlation between δ18O trends recorded by fish remains and belemnites, confirming the paleoenvironmental origin of oxygen isotope variations. Interestingly, temperatures recorded by pelagic fishes and nektobenthic belemnites and bottom dwelling fishes are comparable during the Late Pliensbachian sea-level lowstand but gradually differ during the …

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Réponses du d13C au forçage astronomique dans divers contextes de production carbonatée : le cas du Valanginien du Sud-Est de la France

International audience; Le d13C est un outil fréquemment utilisé pour établir des échelles de temps astronomiques en milieu (hémi-) pélagique. Pourtant le lien entre d13C et forçage astronomique n’est pas toujours clair, tant les sources de carbone sont multiples. Nous avons comparé le d13C à la susceptibilité magnétique (SM) et aux cortèges argileux dans les séries marno-calcaires du Valanginien du Bassin Vocontien (SE France). Ces deux signaux sont fréquemment utilisés pour détecter un forçage astronomique dans les alternances marno-calcaires. Deux intervalles de 400 ka (correspondant à un cycle de grande excentricité) ont été ciblés, l’un avant la crise des producteurs carbonatés associé…

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Astrochronology of the Valanginian Stage from reference sections (Vocontian Basin, France) and palaeoenvironmental implications for the Weissert Event.

12 pages; International audience; High-resolution gamma-ray measurements performed on five biostratigraphically well-dated reference sections from the Vocontian Basin (south-eastern France) are used to develop a new astrochronology of the Valanginian Stage and its subdivisions (i.e. ammonite and calcareous nannofossil zones and subzones). Spectral analyses show a pervasive dominance of 405-kyr eccentricity cycles with the expression of 100-kyr eccentricity, obliquity and precession. Previous rough estimates of Valanginian Stage duration ranged from 3.9 to 6.5 myr but were generally based on less reliable or indirect methods. This study provides a precise duration of 5.08 myr, tuning the ser…

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Long-term lacustrine paleo-productivity and/or paleo-anoxia trends controlled by eccentricity cycles in the continental Autun Basin (France) at the Carboniferous/Permian boundary

<p>The organic-rich lacustrine beds of the Autun Basin (France) were deposited from the late Gzhelian (late Carboniferous) to the Sakmarian (early Permian), encompassing the Carboniferous-Permian boundary (∼299 Ma). Those deposits reach up to 1500 m thick, and correspond to a tropical, intra-mountainous late-orogenic basin infilling associated with the Variscan orogeny (Marteau, 1983; Schneider et al., 2006). Organic-rich and laminated facies are attributed to distal lacustrine environments which sometimes alternate with silty to sandy rich deltaic depositional environments (Mercuzot et al., 2019). The four successive formations (respectively the Igornay, Muse, …

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El Ciclo Ándico de Groeber en la cuenca Neuquina, una revisión y actualización.

A state of the knowledge of the Andean cycle is presented, mainly based on our recent works, butalso on highlights of recent research of many colleagues. This synthesis allowed us to update thegeochronology of its different units. New absolute ages through U-Pb analysis in zircons by differentmethods complement those previously carried out and made possible to accurately limit the ageof these units. We have been able to define the boundary between the Tordillo and Vaca MuertaFormations very precisely between 147 and 146 Ma; the age of the Agrio Formation between 132 and126 Ma, and to present the first absolute ages of the Huitrín Formation. All these data are screenedthrough precise biostra…

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A lacustrine record of the early stage of the Miocene Climatic Optimum in Central Europe from the Most Basin, Ohře (Eger) Graben, Czech Republic.

AbstractThis study reports on a ~ 150 m thick macrofossil-barren sequence of siliciclastic sediments from a Burdigalian age (Early Miocene) freshwater lake. The lake was located within an incipient rift system of the Most Basin in the Ohře (Eger) Graben, which was part of the European Cenozoic Rift System, and had an original area of ≈ 1000 km2. Sediments from the HK591 core that cover the entire thickness of the lake deposits and some of the adjacent stratigraphic units were analysed by X-ray fluorescence spectroscopy (a proxy for element composition) and magnetic polarity measurement. The element proxies were subjected to frequency analysis, which provided estimated sedimentation rates, a…

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Inverted responses of the carbon cycle to orbital forcing in Mesozoic peri‐platform marginal basins: implications for astrochronology

International audience; Astrochronology depends on the faithful record of insolation forcing in climatic proxies, including the carbon isotope composition measured on bulk carbonates (δ13Ccarb). In marginal basins close to carbonate platforms, the source of carbonate is varied, which can impact the record of the astronomical cycles in the δ13Ccarb signal. We compare here the δ13Ccarb values together with detrital and weathering proxies before and during a crisis in the platform carbonate production (Weissert event, Valanginian, ~135 Ma) to document how a change in the carbonate source can affect the record of the orbital forcing by the carbon isotope system. The level of burial diagenesis w…

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Is there an orbital control on the pacing of anoxia across the Aptian-Albian boundary (~113 Ma)?

<p>The stratigraphic interval spanning the Aptian-Albian transition is marked by a cluster of short-lived marine anoxic episodes referred to as Oceanic Anoxic Event 1b (OAE 1b). These short-lived episodes are, from the oldest to the youngest, the Jacob, Kilian, Paquier and Leenhardt events. We here aim at testing the impact of the long Milankovitch cycles (1.2-Myr and 2.4-Myr) on the recurrence of these oxygen-deficiency episodes by establishing a precise astrochronology of the OAE 1b interval from the Col de Pré-Guittard section (Albian GSSP, Vocontian Basin, SE France). The section belongs to the “Marnes Bleues Formation”, which is a …

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Massic magnetic susceptibility and CaCO3 content at the P. ohmi and T. hugii zones from the Rio Argos X.Ag-1 section, southeastern Spain

An orbital floating time scale of the Hauterivian-Barremian transition (Early Cretaceous) is proposed using high-resolution magnetic susceptibility measurements. Orbital tuning was performed on the Río Argos section (southeast Spain), the candidate for a Global boundary Stratotype Section and Point (GSSP) for the Hauterivian-Barremian transition. Spectral analyses of MS variations, coupled with the frequency ratio method, allow the recognition of precession, obliquity and eccentricity frequency bands. Orbitally-tuned magnetic susceptibility provides minimum durations for ammonite biozones. The durations of well-constrained ammonite zones are assessed at 0.78 myr for Pseudothurmannia ohmi (L…

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