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The lagoonal and shallow marine sediments of the Penarth Group in the UK span the Triassic–Jurassic boundary. These sediments contain several disturbed levels with soft sediment deformations (SSDs), such as synsedimentary faults, injective domes, recumbent folds and slumps that are recognised in most basins from SW England and South Wales to NW Northern Ireland. Field observations, notably the close link of the SSDs to active faults, attest an earthquake origin of the SSDs. Fluids, faults, overpressure and lithology guided the style of the SSDs and their distribution in the sedimentary sections. Analysis of the directional data relating to SSDs in each disturbed level shows preferred orientations of deformation, which correspond to the local state of stress at the time. We favour a series of earthquakes, rather than a single mega-event as a trigger of the observed features. The active local extensional tectonic context was driven by the opening of the Permo-Triassic basins in Western Europe. The data from the SSDs in the UK suggest the development of a multi-directional, mosaic-style extensional context to occur during this early phase of the break-up of Pangea. Our integrated tectonic/sedimentary study suggests that directional data from faults, injective domes, recumbent folds and slumps preserved in sediments are reliable to reconstruct past seismic activity and basin geodynamics.

The relationship between palaeoclimate warming and cyclone frequency is still poorly understood, even though tempestites (i.e. storm deposits) may be abundant in Greenhouse period deposits. The Kimmeridgian marl-limestone alternations of the North Aquitaine Platform include abundant tempestites that formed in shallow to moderate-depth marine environments affected by westward-moving cyclones. High-resolution sedimentological and sequence stratigraphic interpretations, combined with biostratigraphy have allowed us to date these deposits. However, changes in cyclone frequency and temperature have never been determined and compared for this interval. In the present work, the relationship between temperature, cyclone frequency and their controlling factors are addressed for the first time. Oxygen isotope analyses were performed on brachiopod and oyster shells and on bulk rock samples from three sections close to La Rochelle, western France. To define a western European temperature tendency for the entire Kimmeridgian, these delta O-18(shell) values were supplemented by new oxygen isotope measurements from Kimmeridgian brachiopod shells of the Burgundy and Jura Platforms. These new delta O-18(shell) values were compared with a selection of published contemporaneous delta O-18(shell) values in order to specify the Kimmeridgian Greenhouse climatic conditions. The resulting overview shows that the average temperature of shallow seawater did not change through the Kimmeridgian while deep seawater warmed close to the early-late Kimmeridgian boundary (i.e. during the Cymodoce zone of the Sub-boreal realm or time equivalent zone). This global seawater thermal homogenization coincides with the most important increase in cyclone frequency recorded through the Kimmeridgian of western France. At the western European scale, a small decrease in temperature took place during the early Kimmeridgian, which is interpreted as a switch in oceanic circulation, on the basis of new mineralogical and elemental analyses performed on the Kimmeridgian of the North Aquitaine Platform. This switch in oceanic circulation may be due to widespread Kimmeridgian extensional tectonic activity, and to proto-North Atlantic seaway opening in particular. This kind of tectonically induced regional divergence from the late Jurassic Greenhouse climate conditions probably diminished or even disappeared at the early-late Kimmeridgian boundary, favouring the global thermal homogenization of marine waters and the increasing frequency of cyclones observed in the present work.

Here in the first part of this publication we discuss the possibilities for the selection of a GSSP for the Berriasian Stage of the Cretaceous System, based on the established methods for correlation in the Tithonian/Berriasian interval. This will be followed, in the second part, by an account of the stratigraphic evidence that justifies the locality of Tre Maroua (Hautes-Alpes, SE France) as the proposed GSSP. Here we discuss the possibilities for correlation in the historical J/K boundary interval, and the evolution of thinking on the positioning of the boundary over recent generations, and in relation to research in the last ten years. The Tithonian/Berriasian boundary level is accepted as occurring within magnetosubzone M19n.2n. The detailed distribution of calpionellids has been recorded at numerous sites, tied to magnetostratigraphy, and the base of the calpionellid Alpina Zone is taken to define the base of the Berriasian Stage. This is at a level just below the distinctive reversed magnetic subzone M19n.1r (the so-called Brodno reversal). We discuss a wide range of magneto­stratigraphic and biostratigraphic data from key localities globally, in the type Berriasian areas of France and wider regions (Le Chouet, Saint Bertrand, Puerto Escano, Rio Argos, Bosso, Brodno, Kurovice, Theodosia etc.). The characteristic datums that typify the J/K boun­dary interval in Tethys and its extensions are detailed, and the correlative viability of various fossil groups is discussed. The boundary level is correlated to well-known J/K sections globally, and a series of secondary markers and proxies are indicated which assist wider correlation. Particularly significant are the primary basal Berriasian marker, the base of the Alpina Subzone (marked by dominance of small Calpionella alpina, Crassicollaria parvula and Tintinopsella carpathica) and secondary markers bracketing the base of the Calpio­nella Zone, notably the FOs of the calcareous nannofossil species Nannoconus wintereri (just below the boundary) and the FO of Nannoconus steinmannii minor (just above). Notable proxies for the boundary are: 1) the base of the Arctoteuthis tehamaensis Zone in boreal and subboreal regions, 2) the dated base of the Alpina Subzone at 140.22 ±0.14 Ma, which also gives a precise age estimate for the system boundary; and 3) the base of radiolarian “unitary zone” 14, which is situated just above the base of the Alpina Subzone.

International audience; In part 1 of this work we discussed the possibilities for the selection of a GSSP for the Berriasian Stage of the Cretaceous System, based on prevailing practical methods for correlation in that J/K interval, traditional usage and the consensus over the best boundary markers that had developed in the last forty years. This consensus has developed further, based on the results of multidisciplinary studies on numerous sites over the last decade. Here in Part 2 we give an account of the application of those results by the Berriasian Working Group (ISCS), and present the stratigraphic evidence that justifies the selection of the locality of Tré Maroua (Hautes-Alpes, SE France) as the proposed GSSP. We describe a 45 m-thick section in the Calcaires Blancs vocontiens – that part of the formation covering the calpio­nellid Chitinoidella, Remanei. Intermedia, Colomi, Alpina, Ferasini, Elliptica and Simplex biozones. The stratigraphic data collected here has been compiled as part of a wider comparative study of complementary Vocontian Basin sites (with localities at Charens, St Bertrand, Belvedere and Le Chouet). Evidence from Tré Maroua thus sits in this substantial regional biostratigraphic and magnetostratigraphic context. For the purposes of the GSSP definition, here we particularly concentrate on the unbroken sequence and biotic markers in the interval immediately below the boundary, the Colomi Subzone (covering circa 675,000 years), and immediately above, the Alpina Subzone (covering circa 725,000 years). Particularly significant fossil datums identified in the Tré Maroua profile are the primary basal Berriasian marker, the base of the Alpina Subzone (a widespread event marked by dominance of small Calpionella alpina, with rare Crassicollaria parvula and Tintinopsella carpathica): the base of the Berriasian Stage is placed at the base of bed 14, which coincides with the base of the Alpina Subzone. Secondary markers bracketing the base of the Calpionella Zone are the FOs of the calcareous nannofossil species Nannoconus wintereri, close below the boundary, and the FO of Nannoconus steinmannii minor, close above. The Tithonian/Berriasian boundary level occurs within M19n.2n, in common with many documented sites, and is just below the distinctive reversed magnetic subzone M19n.1r (the so-called Brodno reversal). We present data which is congruent with magnetostratigraphic and biostratigraphic data from other key localities in France and in wider regions (Le Chouet, Saint Bertrand, Puerto Escaño, Rio Argos, Bosso, Brodno, Kurovice, Theodosia…), and thus the characteristics and datums identified at Tré Maroua are key for correlation and, in general, they typify the J/K boundary interval in Tethys and connected seas.

International audience; European early Eocene (Ypresian) mammalian biochronology, covering a timespan of about 8 myr, includes three distinct MP (Mammal Paleogene) reference levels MP7, MP8+9 and MP10. These are represented in the unique succession of the Minervois (Southern France) by the localities of Fournes (close to MP7), Sainte-Eulalie (close to MP8+9) and Azillanet (close to MP10). Considering homogenous terrestrial organic matter contribution (type III) as suggested by palynofacies and Rock-Eval pyrolysis, we here demonstrate that the organic carbon isotope curve of the predominantly continental Ypresian of the Minervois closely matches the marine standard carbonate carbon isotope curve. The here studied mammalian faunas and their supposed corresponding MP levels can thus be accurately dated and correlated on a global scale. The endemic Fournes mammal fauna, located just above the Eocene Thermal Maximum 2-ETM2, is assigned to mid-Biochron NP11 Calcareous Nannoplankton Zone. Accordingly, the Fournes mammal site is about 2.5 myr younger than the MP7 reference level of Dormaal (Belgium, latest Biochron NP9), about 1 myr younger than the MP7 mammalian locality of Le Clot in the Corbieres (Southern France, late Biochron NP10 or early Biochron NP11) and very close to the Wasatchian Wa-5 mammalian biozone of Wyoming. A mid-Biochron NP12 age is inferred for the endemic Sainte-Eulalie fauna because of its position at the very top of (or just above) the isotopically negative ``ETM3 interval'', whereas the Azillanet fauna, recorded at the top of a delta C-13(org) positive trend above the ``ETM3 interval'', ranges from late Biochron NP12 to early Biochron NP13. Our results indicate that the short-term hyperthermals ETM2 and ETM3 did not affect the endemic character of the mammalian faunas in Southern and Northern Europe during the MP7 to MP8+9 interval. The end of this mammalian endemism likely occurred during the early phases of the EECO (Early Eocene Climatic Optimum) in early late Biochron NP12.

29 pages; International audience; Sedimentological investigations have been carried out in the southwestern part of the Gissar Range (Uzbekistan) in order to document the stratigraphic evolution of a vast Middle–Upper Jurassic carbonate platform developed on the northern margin of the Amu Darya Basin. Two major sequences are distinguished, based on their contrasting facies pattern, platform configuration and carbon isotope signature: (1) a Callovian Sequence and (2) an Upper Jurassic Sequence, potentially Oxfordian to Kimmeridgian in age. A carbonate ramp with a double proximal-distal polarity developed during the Callovian Sequence. Oo-bioclastic grainstones were produced in two permanently agitated shallow water areas developing to the north and to the south. Patch and pinnacle reefs mainly built up close to the storm-wave base, passing distally to pellet- and foraminiferal-oncoid-rich mid-to outer-ramp deposits. The top of the Callovian Sequence is a regional discontinuity that could have formed by subaerial exposure of the platform. This probable hiatus could record a major climatic change associated to the Middle‒Late Jurassic transition. The Upper Jurassic Sequence consists of metre-thick alternations of pellet/algal-pack- to grainstones, microbial oncoid floatstones, ooid grainstones, and mudstones, which have likely accumulated in a vast lagoon protected by a large-scale barrier reef observed south of the study area. Gypsum and anhydrite content gradually increased towards the top of the Upper Jurassic Sequence, ending up with a thick chicken-wire gypsum accumulation recording the progradation of a large-scale sabkha over the lagoon. This phenomenon is related to a progressive aridification and restriction of the Amu Darya Basin that could have begun during the Middle/Late Oxfordian and reached its climax during the Tithonian with massive halite deposition. Comparable events occurred in Jurassic platforms located along the Tethyan margins, pointing to regional and global controls on sedimentation.

International audience; L’étude du biomicrofaciès d’un abondant matériel provenant de plusieurs coupes situées dans trois domaines paléogéographiques distincts et éloignés : Rif externe (Maroc) ; Bassin vocontien (SE France) et Tunisie septentrionale, confirme l’intérêt des associations des principaux groupes de microfaunes pélagiques dans la datation des terrains du Jurassique supérieur et de la base du Berriasien au sein de la Téthys occidentale. Parmi ces groupes, les crinoïdes saccocomidés, qui apparaissent fréquemment dans l’Oxfordien moyen, montrent, dans les trois bassins, une abondance à partir de la zone à Hybonotum et dominent par la suite la microfaune pélagique jusqu’à la disparition relative du groupe au sommet du Tithonien supérieur. Les kystes de dinoflagellés calcaires (dinokystes calcaires), dont deux espèces nouvelles, permettent de définir 10 biozones, dont 7 au moins, ont une valeur générale dans le domaine téthysien. Les biozones, définies tant pour les dinokystes calcaires que pour les saccocomidés, sont corrélées aux zones standards d’ammonites et de calpionelles. Parmi les autres groupes pélagiques, les protoglobigérines, abondantes dans l’Oxfordien supérieur et à la base du Kimméridgien (zone à Platynota), sont rares, voire absentes dans les niveaux sus-jacents ; les microfilaments montrent dans les séries du Rif externe et du Nord de la Tunisie deux niveaux d’abondance, respectivement dans les zones à Divisum et à Beckeri, et disparaissent au sommet de cette dernière zone ; les chitinoidelles permettent de caractériser les niveaux de passage Tithonien inférieur (zone à Ponti)-Tithonien supérieur (zone à Microcanthum) ; les calpionelles, apparaissant au sommet de la zone à Microcanthum, sont dominées par les espèces du genre Crassicollaria dans la zone à Durangites et Calpionella alpina dans la zone à Euxinus (base du Berriasien). Les Globochaete, souvent présents, ne deviennent réellement abondants qu’à partir de la base du Tithonien inférieur (zone à Hybonotum) et sont toujours abondants dans le Tithonien et le Berriasien inférieur. Les radiolaires montrent des répartitions stratigraphiques irrégulières. En utilisant ces différents groupes fossiles, 13 biozones d’extension concomitante sont définies pour l’intervalle stratigraphique étudié ; elles correspondent respectivement à l’Oxfordien supérieur-base du Kimméridgien (zone à Platynota), les zones à Hypselocyclum, Divisum, Acanthicum-Eudoxus, Beckeri, Hybonotum, Darwini-Semiforme, Fallauxi, Ponti, Microcanthum pro parte, partie supérieure de la zone à Microcanthum et inférieure de la zone à Durangites, partie supérieure de la zone à Durangites et inférieure de la zone à Euxinus. Le présent travail vise à établir une zonation biostratigraphique, meilleure et pratique, des dépôts du Jurassique supérieur et de la base du Berriasien des bassins de la Téthys occidentale, notamment en l’absence d’ammonites.

The Congo deep-sea fan is directly connected to the Congo River by a unique submarine canyon. The Congo River delivers up to 2×1012gPOC/yr, a part of which is funnelled by the submarine canyon and feeds the deep-sea environments. The more distal part of the Congo deep-sea fan, the terminal lobe area, has a surface of 2500 km2 and is situated up to 800 km offshore at depths of 4750–5000 m. It is a remarkable place to study the fate and distribution of the organic matter transferred from the continent to the deep ocean via turbidity currents. Forty-two samples were analyzed from the terminal lobes, including sites from the active channel, one of its levees and an abandoned distal channel. Samples were collected using multitube cores and push-cores using a Victor 6000 ROV, which surveyed the dense chemosynthetic habitats that locally characterize the terminal lobes. Palynofacies reveal a remarkably well-preserved, dominantly terrestrial particulate organic matter assemblage, that has been transferred from the continent into the deep-sea by turbidity currents. Delicate plant structures, cuticle fragments and plant cellular material is often preserved, highlighting the efficiency of turbidity currents to transfer terrestrial organic matter to the sea-floor, where it is preserved. Moreover, the palynofacies data reveal a general sorting by density or buoyancy of the organic particles, as the turbulent currents escaped the active channel, feeding the levees and the more distal, abandoned channel area. Finally, in addition to aforementioned hydrodynamic factors controlling the organic matter accumulation, a secondary influence of chemosynthetic habitats on organic matter preservation is also apparent. Palynofacies is therefore a useful tool to record the distribution of organic matter in recent and ancient deep-sea fan environments, an important topic for both academic and petroleum studies.

International audience; The Autunian (Late Gzhelian-Sakmarian, ∼295 Ma) of the Autun Basin (Saône-et-Loire, France) is well known for its lacustrine oil-shales and boghead that were exploited during the 19th and 20th centuries. A study of the kerogen geochemistry, palynofacies, hydrocarbon (HC) distribution of pyrolysates and kinetics on these organic-rich sediments gave indications on the control of lacustrine primary fluid characteristics by palaeoenvironmental settings. Palynofacies results have shown a Botryococcus algae dominance in the boghead, whereas the oil-shales were dominated either by a mixing of terrestrial particles and lacustrine phytoplanktonic/bacterial organic matter (OM), or by a lacustrine OM that suffered biodegradation within the water column. During the Autunian, an increasing trend of degraded lacustrine OM concentration is observed in the successive oil-shales. Geochemical and kinetics analyses showed that, except for the boghead, hydrogen index values were

International audience; A new dinosaur tracksite was recently discovered in the Upper Jurassic deposits from the Oléron Island (Atlantic Ocean, western France). Tracks are located along the coastline in the tidal area of La Morelière near “Pointe de Chassiron”. They were observed in situ in an evaporitic interval from the “Purbeck beds” Unit. Sediments consist of calcite recrystallised after gypsum dissolution within limestone layers which are composed of thin laminites. The track-bearing surface shows abundant mud cracks and some ripple marks. Ichnofossils consist of medium-sized tridactyl footprints of theropods forming a narrow trackway. In order to obtain 3D reconstructions of the track-bearing surface, the trackway was scanned with a resolution of 0.5 mm using an Artec Eva 3D white-light scanner. As indicated by the track dimensions, the probable trackmaker is assigned to a medium-sized non-coelurosaur tetanuran, such as a megalosauroid or an allosauroid theropod. The palaeoenvironmental context is interpreted as a tidal flat in an evaporitic basin. In addition to the tridactyl tracks, we report sauropod- and thyreophoran-like tracks on two other surfaces from Chassiron–La Morelière.

International audience; The Eocene–Oligocene transition (EOT, ~34 Ma) is the largest global cooling of the Cenozoic Era and led the Earth's climatic system to change from a greenhouse to an icehouse mode. Although it is well documented in marine settings, the few studies focusing on continental environments have demonstrated regional heterogeneities. The study core CDB1, located in the Rennes Basin (Western France), is a unique terrestrial (lacustrine–palustrine) record comprising well-preserved and terrestrial-derived organic-rich sediments encompassing the EOT. Clay minerals and the first organic nitrogen isotope record (d 15 N org) of terrestrial origin for this period are used to reconstruct palaeoclimate changes across this key interval. As suggested in worldwide marine and a few continental records, a stepwise transition from warm/humid conditions in the Late Eocene to cooler/drier conditions in the Early Oligocene is confirmed in the area. In addition, an episode of drier conditions in the Late Eocene and humid/dry cycles in the Early Oligocene are suggested. Terra Nova, 00: 1–9, 2016

The Zumaia section, the most complete and representative section of the early Palaeogene (hemi)-pelagic succession of the Pyrenees, is widely acknowledged as a key reference for the Palaeocene–Eocene boundary. New high-resolution δ13Corg of the Zumaia section (−23.8 to −28.8‰) confirms the position of the Carbon Isotope Excursion and enhances the distinction between the different steps of the CIE/PETM event. According to new magnetic susceptibility data and detailed cycle counting, the entire duration of the CIE/PETM in Zumaia is estimated in ∼168 ± 16 ka. Moreover, the investigation of palynofacies and low-field magnetic susceptibility reveal significant detrital influx during the interval. Several magnetic susceptibility phases and trends are recognised and are interpreted in terms of sea-level fluctuations before, during and after the PETM. Coupled with results from other sections, our data reveal the presence of an unconformity followed by an eustatic sea-level rise (TST) in the latest Palaeocene.

The Palaeocene ⁄ Eocene boundary (P ⁄ EB) and the Palaeocene- Eocene Thermal Maximum (55.8 Ma) are defined stratigraphically based on carbon isotope ratios of various materials. Here, the position of the P ⁄ EB is refined in the terrestrial-lacustrine and swampy Vasterival section (Upper Normandy coast, France) by using carbon isotopes measured on dispersed organic matter (d13Corg). Moreover, nitrogen isotopes on dispersed organic matter (d15Norg) are, for the first time in the Palaeogene record, associated with carbon isotope and lithological data to constrain palaeoclimatic and environmental changes around the P ⁄ EB in a terrestrial environment. Humid-dry fluctuations before and during this key interval in Earth history are suggested.

Pedogenic nodules, calcitic shells, dispersed organic carbon and bulk rocks affected by low diagenesis are judged to be reliable tools for carbon-isotope chemostratigraphy. Up to now no systematic study has been carried out to check the reliability of fossil wood material for carbon-isotope chemostratigraphy in terrestrial settings. The 235-m thick Wealden facies sediments of the Danube-Bouchon quarry at Hautrage (Hautrage Clays Formation, Mons Basin, Belgium) encompass dark to grey clays and sands, rich in organic matter and coalified-charcoalified fragments of fossil wood, deposited in an alluvial plain during middle Barremian to earliest Aptian. We measured and compared the carbon-isotope ratios of 110 levels of the stratigraphic succession for dispersed organic carbon (δ13CDOC), and fossil wood (δ13CWOOD) collected in the same geological level. In the whole succession, the averages of δ13CDOC and δ13CWOOD have a significant difference of about 0.9‰. The δ13CWOOD is usually heavier than the δ13CDOC, which is consistent with measurements on different constituents of modern trees (branches versus leaves and tissues). In one single stratigraphic level, the variability of δ13CWOOD is much higher (up to 7.3‰) than that of δ13CDOC (0.4‰). Four main causes may explain these results. Firstly, the δ13CDOC averages the isotopic signal of different compounds and tissues (such as leaves, seeds, cuticles) as they become mixed and dispersed. The δ13CWOOD reflects the carbon-isotope ratio of a small part only of one single tree, which is a complex system with δ13C variations over a range of 4‰. Secondly, there is strong δ13C variability between different species of plants. In Hautrage, several gymnosperm genera were collected (including Podocarpoxylon, Taxodioxylon, Brachyoxylon, and Thujoxylon) and numerous fern taxa. Thirdly, coalification and charcoalification can affect the δ13C of the DOC and the various kinds of woods in a different way. Fourthly, the wood fragments may be reworked several times from more ancient geological levels, especially in the alluvial plain environment of Hautrage where thick levels of fluviatile coarse sand deposits are observed. However, in the whole succession, both δ13CWOOD and δ13CDOC curves show similar trends. This suggests that carbon-isotope curves on fossil wood can be matched to carbon-isotope curves on DOC. For the whole trend fossil wood is a relatively good chemostratigraphic tool when sufficient samples are measured in the succession. Whenever possible both control of the wood taxa, and estimation of degree of (char)coalification are however recommended. In one single level, charcoal has more stable δ13CWOOD values than δ13CWOOD of coalified fragments. The δ13C positive trend can be due to several causes, including global pCO2 variations and/or regional changes and/or local environmental conditions in the alluvial plain. If global, the dating of the Hautrage succession may be refined to the late Early Barremian-early Late Barremian by matching palynological and carbon-isotope chemostratigraphical data. © 2010 Elsevier B.V. All rights reserved.

International audience; Marine and terrestrial sediments of the Valanginian age display a distinct positive δ13C excursion, which has recently been interpreted as the expression of an oceanic anoxic episode (OAE) of global importance. Here we evaluate the extent of anaerobic conditions in marine bottom waters and explore the mechanisms involved in changing carbon storage on a global scale during this time interval. We asses redox-sensitive trace-element distributions (RSTE; uranium, vanadium, cobalt, arsenic and molybdenum) and the quality and quantity of preserved organic matter (OM) in representative sections along a shelf-basin transect in the western Tethys, in the Polish Basin and on Shatsky Rise. OM-rich layers corresponding in time to the δ13C shift are generally rare in the Tethyan sections and if present, the layers are not thicker than several centimetres and total organic carbon (TOC) contents do not surpass 1.68 wt..%. Palynological observations and geochemical properties of the preserved OM suggest a mixed marine and terrestrial origin and deposition in an oxic environment. In the Polish Basin, OM-rich layers show evidence for an important continental component. RSTE exhibit no major enrichments during the δ13C excursion in all studied Tethyan sections. RSTE enrichments are, however, observed in the pre- δ13C excursion OM-rich "Barrande" levels of the Vocontian Trough. In addition, all Tethyan sections record higher Mn contents during the δ13C shift, indicating rather well-oxygenated bottom waters in the western Tethys and the presence of anoxic basins elsewhere, such as the restricted basins of the North Atlantic and Weddell Sea. We propose that the Valanginian δ13C shift is the consequence of a combination of increased OM storage in marginal seas and on continents (as a sink of 12C-enriched organic carbon), coupled with the demise of shallow-water carbonate platforms (diminishing the storage capacity of 13C-enriched carbonate carbon). As such the Valanginian provides a more faithful natural analogue to present-day environmental change than most other Mesozoic OAEs, which are characterized by the development of ocean-wide dysaerobic to anaerobic conditions.

The early Cretaceous Bernissart lake deposits (Mons Basin, Belgium) constitute an important historical site in the field of palaeontology. In this study, we focus on the organic matter (OM) content of the 50 m-long borehole core, "Ber 3", drilled at Bernissart. Organic data (Rock-Eval, palynofacies, C/N ratios) and carbon-isotope measurements on bulk OM and selected, isolated wood fragments were collected. The OM distribution exhibits two total organic carbon (TOC) cycles (12 m and 38 m-thick, respectively) that are stacked in a lower frequency cyclic pattern. A general increase of in situ aquatic production and preservation of OM through time is evidenced within the freshwater masses. A spectral analysis of a high-resolution gamma-ray record demonstrates that the sedimentation was controlled by orbitally-induced climatic changes. Precession, obliquity and short- and long-term eccentricity cycles are recognized. The 12 m-thick and the 38 m-thick TOC cycles fit well with a 100 kyr short-term and a 400 kyr long-term eccentricity cycle, respectively. Long-term organic fluctuations are interpreted as resulting from orbitally-induced fluctuating lake levels through time. Carbon-isotope evolution of bulk OM is thought to reflect firstly two local patterns of sedimentation: (1) the changing contribution of in situ amorphous organic matter versus terrestrial OM, and (2), the possible influence of enhanced productivity. The negative δ13CWOOD trend recorded at Bernissart seems equivalent to published coeval δ13CWOOD and δ13CCARB in the Upper Barremian to Lower Aptian. This trend noted at Bernissart is thus regarded as reflecting changes of the carbon-isotope ratios of atmospheric CO2. Previous presented palynological data suggest a "middle" Barremian to Lowermost Aptian stratigraphic range for the succession at Bernissart. According to this new dataset, we refine the age-assignment for Bernissart: the duration of deposition is now estimated to range between 0.55 and 2.2 myr in the Upper Barremian to Lowermost Aptian.

The Taskomirsay section (South Kazakhstan) is a unique Pliensbachian-Toarcian sequence of lignites, clayey layers and silty-sandstones deposited in a fluvial/lacustrine environment with nearby swampy areas. This period, characterized by a drastic climate change, has been particularly studied in Western Tethyan marine environments, whereas very few studies focused on continental settings. Paleoflora analyses, associated with a multi-isotope approach, based on well-preserved Type-III bulk organic nitrogen isotopes (δ15Norg) and hydrogen isotopic composition (δ2H) of n-alkanes, were developed to document paleoclimatic changes in the area. Sporomorph associations and fossil woods revealed a globally warm- to cool-temperate climate – characterized by Xenoxylon, a conifer morphogenus biogeographically related to cool/humid settings – apart from slightly less humid and warmer conditions in the early Toarcian. Warmer conditions are supported by reconstructed Mean Annual Air Temperatures (MAATs), based on the first branched glycerol dialkyl glycerol tetraethers (brGDGTs) ever recorded in the Early Jurassic. Nevertheless, no drastic changes were recorded in the δ15Norg values; its signal being attributed to tenuous equilibrium between water- and nutrient-availability via intense N-recycling. Based on n-alkane distributions, sources of organic matter were separated in two pools: (i) a purely terrestrial (n-C27) and (ii) an “aquatic” pool (n-C23) constituted of vegetation that thrived under almost permanent water supply. The n-alkane δ2H values (− 248 to − 151‰) as well as their amounts and average chain lengths (ACL) are in agreement with cool-temperate conditions in the Pliensbachian and less humid/warmer conditions in the early Toarcian. The isotopic difference between δ2H values of n-C27 and n-C23 (Δ2Hter-aq) suggests enhanced seasonality during the Pliensbachian-Toarcian transition and low seasonality in the early Toarcian, in agreement with temperate climate-regime. Finally, contrasted response to paleoclimate changes between markers suggests different spatial integration of those proxies. The role of sea-level variations for δ2H values might also resolve this contrasted response.

International audience; L’étude de plusieurs centaines de lames minces issues de plusieurs dizaines de coupes appartenant à trois domaines paléogéographiques différents et bien éloignés : Rif externe (Maroc) ; Bassin vocontien (SE France) et Tunisie septentrionale, a permis de mieux caractériser l’extension stratigraphique du groupe des crinoïdes pélagiques rovéacrinides saccocomidés. Ce groupe fossile qui apparaît fréquemment dans l’Oxfordien moyen, montre, dans les trois bassins étudiés, une abondance à partir de la zone à Hybonotum (base du Tithonien inférieur) et domine, par la suite, la microfaune pélagique jusqu’à la disparition relative du groupe au sommet du Tithonien supérieur, à la limite des sous-zones A2 et A3 des calpionelles. L’analyse minutieuse des sections de pièces squelettiques de ce groupe fossile a permis de caractériser 47 types de sections, répartis en six groupes différents. Ces sections sont décrites et nommées sur la base de leurs formes géométriques. La plupart d’entre elles se rencontrent dans des niveaux stratigraphiques contemporains et dans des coupes bien éloignées. Plusieurs de ces sections sont caractéristiques d’un intervalle stratigraphique précis, soit par leurs formes géométriques, soit par leurs fréquences relatives. La répartition stratigraphique des sections inventoriées, qui n’avaient jusqu’alors qu’un intérêt stratigraphique restreint, permet de caractériser 7 biozones d’association et de fréquence relative pour l’intervalle Oxfordien supérieur-Tithonien supérieur. Ces biozones sont corrélées avec les zones d’ammonites.

An unusual succession of facies locally deposited around the Jurassic–Cretaceous boundary in the Boulonnais (northern France) is attributed to a tsunami event by comparison with recent tsunami deposits. This sedimentary succession includes basal erosion with reworked lithified blocks, soft-sediment deformations, an erosional conglomerate overlain by wood fragments and clays containing continental and marine fossils in one setting and conglomerate with mixed fauna in an other setting. The tsunami probably affected the coast of the Boulonnais area of the London–Brabant Massif. The origin of the event is unknown. It was most probably triggered by an earthquake, but other origins such as volcanic eruptions, a giant landslide, or even the impact of an extraterrestrial bolide into the ocean may also be considered.

In order to precise the paleogeographic extension of the climatic variation known at the Jurassic/Cretaceous boundary, the sedimentary organic matter (palynofacies and Rock-Eval) and the clay minerals content of Berriasian sediments of the Sidi Kralif Formation are studied on the Jebel Meloussi section, central Tunisia. Standard sedimentological and palynofacies analysis allow to reconstruct the bathymetric curve and the sequence stratigraphic scheme. Using existing biostratigraphy based on calpionellids and ammonite zonation, the sequence stratigraphic interpretation can be correlated with the established eustatic chart. Clay mineral assemblages are characterized by a shift in the kaolinite content, recorded at the end of the calpionellid zone B, at the early/middle Berriasian boundary, at a time of high long-term sea-level (MFS Be2, second order eustatic peak). A contemporary change in the clay mineral assemblages, interpreted as a climatic change, is known from the boreal area, and from the northern margin of the Tethys Sea. That change is also documented southerly in southern Morocco (Agadir area), on the Atlantic domain. A late Tithonian to early Berriasian dry and cooler phase is replaced by a middle to late Berriasian more humid phase, indicated by a general increase in kaolinite in the clay mineral assemblages. The trend from a dry climatic phase to a more humid one, recorded on the boreal domain and along the northern margin of the Tethys is also recorded in lower paleolatitudes of Tunisia, on the southern margin of the Tethys, in better dated outcrops than the ones of Morocco. The results obtained in Tunisia show that the beginning of the climatic change was precisely synchronous on both margins, and occurred within the same long-term high sea-level context.

International audience; The middle Oxfordian warming climate and sea-level rise initiated the development of vast carbonate platforms in some western European basins. At the same time, however, siliciclastics and siliceous sponges dominated certain marginal areas of the Iberian ramp. There, siliciclastic input was particularly prominent during the latest Oxfordian and may have been related to a global sea-level fall, synsedimentary tectonic activity, or humid climatic conditions in the hinterland. Field analyses and computer modelling have been previously used to determine the factors that controlled sedimentation. However, it is still unclear if the specific conditions that prevailed during the latest Oxfordian were due to eustasy, tectonics or climate, and when precisely they occurred. Here, we document major changes in sedimentological, micropalaeontological, and mineralogical records on the Iberian ramp during this interval. Detailed sedimentary facies and palynofacies analyses combined with sequence-stratigraphic and cyclostratigraphic analyses of the Ricla Barranco section enable the establishment of a highresolution time frame. Based on the quartz and mica percentage fluctuations, one large- and seven small-scale sequences are defined. The large-scale sequence boundaries correlate with third-order sequence boundaries Ox 8 and Kim 1 defined by Hardenbol et al. (1998). The large-scale maximum-flooding surface corresponds to the base of the most calcareous interval and to the maximum abundance of marine phytoplankton and opaque, equidimensional phytoclasts. The small-scale sequences correspond to the 100-kyr orbital eccentricity cycle. Calcareous nannofossils and clay minerals were used as palaeoclimatic proxies. Nannofossil abundances and fluxes are lower in the upper part than in the lower part of the interval studied, suggesting a decrease in seasurface trophic conditions, also shown by an increase in the relative abundance of oligotrophic taxa. This upper part is also characterised by an increase in smectite, which coincides with the base of the large-scale highstand deposit, and is interpreted as reflecting the establishment of dry conditions. A first increase in smectite occurs in the lower part of the succession, and coincides with high percentages of quartz and mica. This latter mineralogical assemblage is interpreted as recording the onset of the Late Jurassic to Early Cretaceous rifting stage, which occurred just before the Planula-Galar ammonite subzone transition. The present study points out a return toward optimum conditions for carbonate sedimentation only 300 kyr after the prominent increase in siliciclastic input due to tectonic activity. The recovery of carbonate production was accompanied by a global sea-level rise and by decreasing rainfall on nearby land.

International audience; The Cap d'Ailly area (Upper Normandy, France) shows several terrestrial–lagoonal sections recording the negative carbon isotope excursion (CIE) associated with the Paleocene–Eocene Thermal Maximum (PETM; 55.8 Ma). A study of the biomarkers and spore/pollen content of the Vasterival section gave com-plementary information on paleofloral changes that occurred around the Paleocene–Eocene (P–E) bound-ary. Aliphatic hydrocarbon fractions revealed a high abundance of vascular plant biomarkers, including tricyclic diterpanes derived from conifers, fernenes derived from ferns and des-A-triterpenes derived from angiosperms. Whereas the vegetation of the depositional environment surroundings seemed alter-nately dominated by ferns and angiosperms (revealed from biomarkers), the regional flora seemed dom-inated strictly by angiosperms such as Juglandaceae (revealed by pollen). Spore/pollen assemblages revealed no major turnover in the paleovegetation, but slight variation in vegetation composition. How-ever, both biomarkers and spores/pollen exhibited two intervals of rapid floral change: the first occurred around the P–E boundary and the second at the top of the strictly terrestrial unit that coincides with a marine transgression. Comparison of the data with published paleoclimatic results, obtained from the same samples, indicated that the first interval of floral change correlates with strong paleohydrological perturbations, whereas the second is linked to an increasing marine influence.

International audience; Utilizing bio- and chemostratigraphy, we propose an integrated dating of the upper part of the continental ``Sparnacien des Corbieres'' and the overlying marine ``lower-middle Ilerdian'' succession of Albas-Le Clot (Corbieres, France), in order to refine the position and age of the Le Clot mammalian locality. Our data show that this locality, which has yielded a mammal fauna early Ypresian in age (close to MP7, Mammal Paleogene level), is located above the end of the carbon isotope excursion (CIE) the base of which defines the Paleocene-Eocene boundary. The Le Clot mammalian locality is therefore younger than the Paleocene-Eocene Thermal Maximum (PETM), and also younger than the Dormaal MP7 reference fauna in Belgium, which is correlated with the onset of the CIE (nannoplankton Zone NP9b). Moreover, we demonstrate that the Le Clot mammalian locality is older than the Eocene Thermal Maximum 2 (ETM2) event, located in the lower part of NP11 Zone. Associated with the ages of benthic foraminifera and dinocysts observed in the succession, our delta C-13(org) chemostratigraphy suggests that the Le Clot locality is correlated to the upper NP10-lower NP11 Zones. The refined location of the CIE in the Albas-Le Clot section is discussed because two carbon isotope excursions are potentially recorded in the upper ``Sparnacien des Corbieres'', here recognized as mainly Thanetian in age.

International audience; The paralic flora and fauna from the Late Jurassic of Chassiron (Oléron Island, western France) are described. The Tithonian-aged bonebeds of Purbeck facies of this locality have yielded a rich and diverse vertebrate assemblage including fishes, amphibians, reptiles and mammals, alongside numerous plant and invertebrate remains. The Chassiron locality thus appears as a peculiar Konzentrat-Lagerstätte in which most of the palaeoecosystem's biological components (both aquatic and terrestrial) have been preserved. The depositional environment was probably subject to salinity fluctuations, as indicated by the co-occurrence of freshwater and euryhaline organisms. This is one of the richest localities and the first mammal-bearing site known from the Jurassic of France.

The stratigraphy of the Late Paleocene-Early Eocene has been revised in Avesnois thanks to drillings supporting a geological mapping project. Detailed sampling and analyses were performed along selected drillings, among which sedimentological, mineralogical, chemostratigraphic (δ13Corg), biostratigraphic and palynological data have been obtained. New Mbs/Fms are defined around the Paleocene-Eocene boundary (PEb) and compared to the lithostratigraphic nomenclatures of the Belgian and Paris Basins (Steurbaut, 1998; Aubry et al., 2005). Biostratigraphy based on the study of foraminifera and mammal fauna, palynological content and chemostratigraphy enable correlation to be established between adjacent basins as well as sea level and landscape evolutions to be refined during this critical interval. Upper Thanetian marine units In the AVE 007-drilling (Mormal Forest, Locquignol, between Englefontaine, Landrecies and Maroilles villages), the Coniacian chalk is overlain by a flint conglomerate, whose sandy-clayey matrix contains Thanetian pollen and dinocysts. Widespread in Avesnois and containing often reworked Upper Cretaceous foraminifera and occasionally glauconite, this unit constitutes the Vervins Mb (cf. 'Argile a silex de Vervins' interpreted as a marine conglomerate by Gosselet, 1879). It is often overlain by the Mondrepuis-Bettrechies Sand Mb (cf. 'Sable verts de l'Avesnois'), a thin sandy glauconiferous unit, more clayey and silty westward (cf. 'Tuffeau de Valenciennes' Mb). The three Mbs constitute the Hainaut-Valenciennois Fm and can be correlated to the Belgian Grandglise Mb (upper part of the Hannut Fm) and Bois-Gilles Fm, and to the Paris Basin Châlons-sur-Vesles and Bracheux Fms, all Thanetian in age. Uppermost Paleocene to lowermost Eocene terrestrial units In AVE 007 the Vervins Mb is unconformably overlain by flint gravels (Mormal Mb), then a pyritic sand (Le Quesnoy Sand Mb, cf. 'Sables et Gres du Quesnoy' of Gosselet, 1890), and a lignitic clay (Locquignol Mb), silty and ochreous at the top. All but the top ochreous paleosol contain spores and pollen grains and are devoid of dinocysts, they were thus probably deposited in terrestrial environments. The Carbon Isotope Excursion (CIE) of the PEb begins below the top of the sandy unit and continues in the lignitic clay. The palynological study confirms the Locquignol Mb's earliest Eocene age and allows correlation with the base of the Tienen Fm. To the East of AVE 007 along the Belgium-France border, fluvial fossiliferous gravels and sands have been studied in past sand quarries (Erquelinnes Sand Mb). Above a sharp unconformity, they i) overly Upper Thanetian marine sands (Bois-Gilles Fm, NP9a, then Grandglise Mb, NP8), ii) contain a mammal fauna referred as MP7 in the Mammalian biochronological scale for the European Paleogene (Missiaen et al., 2013) and iii) record the first part of the CIE onset in the basal fossiliferous gravel and marl beds. Three km west of Erquelinnes and toward AVE 007 a few drillings have recognized a sandy and pyritic unit containing resinite fragments, lignite and peat beds (Vieux Reng Mb), overlying a thin basal flint gravel bed (Mormal Mb). These five Mormal, Le Quesnoy, Locquignol, Vieux-Reng and Erquelinnes Sand Mbs form the Sambre Fm. Such fluvial gravels and sands, more or less lignitic, clayey or marly are widespread in northern France and southeastern Belgium. They belong to the so-called Upper "Landenian" and are correlated to the Tienen Fm. In AVE 007, they record the CIE onset marking the PEb and 2.5 m of Upper Paleocene fluvial units, in contrast with Belgian drillings such as Doel and Kallo where a hiatus is present at the PEb. Lower Ypresian hiatus and marine units In AVE 007, a laminated silty unit overlies the Locquignol Mb, contains dinocysts Wetzeliella sp. and agglutinated foraminifera similar to those of the base of the Orchies Clay Mb. Widespread in Avesnois-Valenciennois that marine unit is named Avesnois Mb, it is locally richer in very fine sand, and correlated to the base of the Kortrijk Clay Fm (Ieper Gp). In Avesnois, Sparnacian lagoonal units are absent upon the terrestrial ones described above, again marking a reverse trend when compared with the Belgian and adjacent Basins. This may result from restricted terrestrial environments coinciding with Variscan accidents and structural highs between the Artois anticline and Ardenne Masssif, or to their deposition followed by subsequent erosion prior to the Lower Ypresian marine transgression (cf. sea level drop 2 of Dupuis et al, 2011). Correlations and PETM impact on land All terrestrial units here described fill fluvial channels incised in marine Thanetian and older units such as the Cretaceous or the Variscan basement in Avesnois and Belgium, as already reported elsewhere in northern France (cf. sea level drop 1 of Dupuis et al., 2011). They exhibit locally cross stratification, lignite, flora or vertebrate fauna, for example at Leval, Hoegaarden and Dormaal, and/or are intensively silicified with scarce root or leaf casts. Similar fluvial sediments and silcretes are recognized in the first Sparnacian units and paleogeography of the Paris, Dieppe-Hampshire and London Basins, where the PEb is also present, the CIE being recorded on thicknesses between 3 m (as in AVE 007) to >20 m (as in Sinceny). These features may be regarded now as constant in those Sparnacian landscapes recording the PETM, with very rapid lateral and vertical facies shift, particular paleosols, a few fossiliferous fluvial to lacustrine units and variable deposition rates/sediments preservation. Terrestrial sediments, flora and fauna have been described there before the CIE onset as well, for example at Cobham, Vasterival or Rivecourt (e.g. Smith et al., 2014). Lihons, an intermediate outlier situated between AVE 007 and Sparnacian sites of those basins has further been investigated: marine Thanetian sands are overlain by thin fluvial, lacustrine then lagoonal sediments, the two latter recording the CIE of the PETM on an interval 4 m thick. Here again the basal terrestrial sediments have been deposited before the PEb. In AVE 007, depositional environments are fluvial for the Mormal and Le Quesnoy Mbs, and evolve toward flood plain then palustrine ones for the Locquignol Mb, probably here after the river bed migration, but still recording sporo-pollen fluvial inputs from the hinterland, the whole indicating a rather humid subtropical climate. Compared to the Locquignol Mb, the sporopollinic assemblage of the Mormal and Le Quesnoy Mbs (below the CIE onset) is different, particularly regarding the Normapolles distribution, the Tricolpates, Tricolporates and Monocolpates relative pollen abundances and the pollen ratio of Plicapollis pseudoexcelsus/Juglandaceae. In the three Mbs, rapid vertical variations characterize pollen and fern spores assemblages, with peaks of particular taxa reaching 25% of the total counts, such as for P. pseudoexcelsus, T. platycaryoides, C. dorogensis, P. mcgregorii, T. robustus. They suggest rapid floral changes in the catchment and/or sources changes in the surrounding landscapes compartments for the rivers supplying the fluvial sediments. Resinite particles are irregularly abundant as well as microcharcoals are occasionally abundant, notably slightly before the CIE onset and 1.5 m above it, still within the CIE. The clay mineral assemblage is homogeneous along marine Thanetian units and strongly dominated by Illite-Smectite (IS) mixed layers, whatever the facies, while it is more variable in the marine Ypresian silts (abundant IS, followed by Kaolinite, Illite, Chlorite and Vermiculite). In contrast terrestrial units are dominated by IS followed by Kaolinite, Illite and very rare Chlorite, and no variation is observed across the PEb. Those data would suggest that major environmental changes have regionally begun before the PETM, at the very end of the Paleocene, when terrestrial realm has settled, in relation with a regional uplift. Clay minerals reflect constant reworking of preexisting weathering profiles established upon Cretaceous strata and Variscan basement, while vegetation modifications are subtle and more likely attributable to changes of depositional environments

International audience; The Paleocene-Eocene boundary (55.8 Ma) is associated with the Paleocene-Eocene Thermal Maximum (PETM), which is characterized by a negative Carbon Isotope Excursion (CIE), reflecting a major perturbation of the carbon cycle, and by an extreme and rapid global warming. The Cap d'Ailly area (Upper Normandy, France), in which previous studies have revealed the Paleocene-Eocene transition, is a reference locality for organic-rich terrestrial and lagoonal deposits of the "Sparnacian" stage, widespread in Northwestern Europe. In this study, we focus on the organic matter content of the Vasterival section. Organic data (Rock-Eval, palynofacies, biomarker analyses and compound specific isotope analyses) were acquired in order to constrain the paleoenvironmental and paleohydrological changes that occurred at the Paleocene-Eocene boundary. Stable carbon isotope compositions of higher plant leaf wax n-alkanes reveal a CIE of − 4.5 ‰, extending throughout the second half of the studied section. Palynofacies observations reveal: (i) an abrupt shift from a closed, quiescent marsh pond to an open eutrophic swamp subjected to algal blooms, concomitant with the onset of the CIE; and (ii) the evolution from a swamp to a tidal flat due to the marine transgression that occurred during the PETM. Higher plant biomarkers and their hydrogen isotopic composition compared to nitrogen analyses suggest: (i) dry episodes just before the PETM that may help to understand the triggering of this hyperthermal event; (ii) a moister climate associated with a stronger seasonality during the early PETM.

International audience; Valanginian sedimentary archives display a positive anomaly in the carbon-isotope record which is associated with a crisis in neritic and pelagic carbonate production. This study aims to reconstruct the evolution of palaeoenvironments in the Jura area and the Vocontian Basin during late Berriasian and early Valanginian times, in order to better understand the controlling factors leading to the Valanginian episode of major environmental change. Three sections along a transect through the Jura platform (Switzerland and France) and the Vocontian Basin (France) have been studied. Stratigraphic correlations have been established by combining biostratigra- phy (benthic foraminifera, ammonites and calpionellids), with geochemistry (δ13C trends) and sequence stratigraphy. A change from a rimmed ramp to a swell-dominated ramp morphology is observed through the Berriasian-Valanginian boundary. The disappearance of the barrier appears to have been controlled by large sea-level variations in combination with the arrival of significantly more humid climate conditions. This barrier played a major role in the distribution of geochemical, mineralogical and palynological fluxes towards the basin: during the Berriasian, continental fluxes (detrital particles, nutrients, pollen and spores) were buffered by the platform morphology, whereas in the early Valanginian they were more readily transported towards the basin. The initiation of a major transgression onto lateritic soils, leading to their intense reworking, instigated a fertilization of ocean waters during the earliest Valanginian and with that a change towards heterozoan carbonate production, and subsequently to the demise of the already weakened carbonate platform

We present new data constraining the Late Jurassic to Early Cretaceous evolution of the Southeastern French basin (SFB). Meso-scale faults with displacement of several decimeters to 1–2 meters were sampled for geometric and kinematic data analysis and the faulted and un-faulted sedimentary units were examined for sedimentologic and bio-stratigraphic purposes. Small-scale faults were also extensively collected to determine the local stress states during this period. Meso-scale normal faults formed during sediment deposition or before its complete lithification attest of a recurrent activity in the Late Jurassic to Early Cretaceous period in an overall extensional context. The fault network cutting the Oxfordian to Aptian sequences included normal faults of various trends, ranging between WSW-ENE and NNW-SSE. We show that the deformation mechanism in the SFB drastically changed in the Jurassic-Cretaceous transition (latermost Tithonian?), with the direction of extension rotating from a WNW-ESE to a NNE-SSW direction. Lateral thickness variation of the sequences, redistribution of sediments, faulting at various scales concur that the Early Cretaceous period marks a tectono-stratigraphic reorganization of the basin. We suggest that it traduces the rifting and later opening of the North Atlantic (main branch and bay of Biscay branch).

15 pages; International audience; In western european basins, lowering of relative sea-level during the Late Jurassic-Early Cretaceous led to the widespread deposition in numerous basins of so-called Purbeck facies. Age-assignment and longdistance correlations are difficult to establish in such shallow marine to continental deposits, where ammonites are generally lacking. This paper aims to present new biostratigraphical and sedimentological data from the Phare de Chassiron section, located at the western part of the Aquitaine Basin (SW France), where Purbeck beds crop out. Marine bands, interfingered within the Purbeck beds, allow refining the age-assignment of these beds using dinoflagellate cysts, calcareous nannofossils and magnetostratigraphy. Most of the Purbeck beds appear to have a Tithonian age. Uppermost beds of the section, although not precisely dated, are not younger than the Early Berriasian. Field sedimentology, palynofacies and trace-element data (strontium) on carbonates, allow depositional environments to be characterized and a sequence-stratigraphy scheme to be established. This section provides an unique, continuous record, within the Aquitaine Basin, of the final exposure, during the Tithonian, of the former Late Kimmeridgian open-marine platform. The Phare de Chassiron may be considered as one of the most important exposures of Purbeck facies of Tithonian age in Europe.

International audience; Late Jurassic coral reefs are present in the Western High Atlas of Morocco along the eastern paleomargin of the young Atlantic Ocean. The Izwarn section shows two reef units made of scleractinian corals and microbialites, included in a progradational shallowing-upward succession. Changes in reefal composition and structure observed in a ca. 50 cm-thick interval at the base of the reef unit 1 are interpreted to represent the first well-documented ecological succession in Late Jurassic reefs. Bioclastic deposits, sparse and poorly diversified corals (five genera) preserved in life position, and finally a more diversified coral assemblage (11 genera) building a reef framework with stromatolitic crusts reflect pioneer, colonization and diversification stages, respectively. A specific depth window, where light was reduced but sufficient for a catch-up growth mode and below the erosive action of waves, probably at the lower slope of a fore-reef area, has made possible the development and the record of this ecological succession. With a more diversified coral assemblage (16 genera), the reef unit 2 reflects shallower and well-agitated waters of a fore-reef area. Overlaying this second reef unit, the upper part of the section reveals back-reef deposits made of reworked reef elements, whereas a putative reef crest area is not recorded.

International audience; The contribution of event deposits to various basin fills can be very significant, higher than 90% in some cases. Events may lead to the formation of marl–limestone alternations, which can also result from cyclic changes in sea level or climate, for example. The marl–limestone alternations of the Late Jurassic of western France contain abundant coarse-grained accumulations that resemble storm deposits described in other western European successions. The detailed analysis of facies evolution and hierarchical, high-frequency stacking pattern of depositional sequences of the Phare de Chassiron section (Ile d'Oléron, western France) allows the controls on marl–limestone formation to be defined. This section contains nearshore and shallow-marine mud deposits that were exposed to high-energy events. Elementary, small-, and medium-scale depositional sequences are defined. The stacking-pattern and the duration of these sequences suggest an orbital control on sedimentation. Precession (20 ka) cycles notably controlled the formation of elementary sequences that correspond to marl–limestone alternations. The deposition of marly or carbonate mud occurred in this storm-dominated system because of muddy sea beds, the gentle slope of the shelf, and the great amount of particles in suspension, which reduced water energy resulting from storms. Sediment supply was also sufficient to limit bioturbation and favour the preservation of numerous storm deposits. The production of carbonate mud was localised on positive structures and partly controlled by Milankovitch-scale sea-level cycles. Transport by storms of carbonate mud to the adjacent marly depressions during high carbonate production periods led to the formation of calcareous beds. Marl–limestone alternations in the Late Jurassic of western France therefore result from the combined effects of cyclic changes in carbonate production and high-energy, episodic events.

International audience; Two sections corresponding respectively to the Shal (Callovian – Lower Berriasian) and Kolur Formations (Berriasian – Valanginian in the sampled interval) have been studied in the Talesh Mountains (North-West Iran), an area whose sedimentary successions formed on the northern margin of the Eastern Tethys during the Mesozoic. This study allowed the identification of the different calpionellid zones and sub-zones defined in basin successions of the Western Tethys. In the upper part of Shal Formation the Chitinoidella boneti (base of the Upper Tithonian) and B1 sub-zones (base of the Calpionella alpina zone, lowermost Berriasian) have been recognized. The rich and diverse calpionellid faunas allowed us to recognize in the Kolur Formation B3 (top of the C. alpina zone), C1, C2 (Calpionella elliptica zone), D1, D2, D3 (Calpionellopsis zone) subzones and E (Calpionellites zone) and F (Tintinnopsella zone). The E zone has been subdivided in two sub-zones: E1 and E2, which is characterized by the disappearance of the genus Calpionellopsis. Thirty calpionellid species have been described. Fifteen of them are new: Calpionellites medius nov. sp., Calpionellites minor nov. sp., Remaniella longocadischiana nov. sp., Remaniella minicadischiana nov. sp., Tintinnopsella curva nov. sp., Tintinnopsella duranddelgai nov. sp., Tintinnopsella elmii nov. sp., Tintinnopsella largovalata nov. sp., Tintinnopsella lehegarati nov. sp., Tintinnopsella longovalata nov. sp., Tintinnopsella maxilonga nov. sp., Tintinnopsella minicarpathica nov. sp., Tintinnopsella pseudoblonga nov. sp., Tintinnopsella pseudocarpathica nov. sp. and Tintinnopsella pseudosimplex nov. sp. Amongst the other pelagic microfossil groups, Globochaete and calcispheres (“microproblematics”), often abundant in Western Tethyan Upper Jurassic – Lower Cretaceous pelagic successions, are absent in the Shal Formation and extremely rare in the Kolur Formation despite its lithofacies usually suited for preservation of such microfossils. It is worth noting that in Kolur section the peak of Cadosina fusca in the D1 sub-zone and the occurrence of Stomiosphaera wanneri in the C zone have been observed similarly to successions of Moroccan external Rif. As in most basins of the Western Tethys, Saccocoma remains are frequent in the upper part of the Shal Formation and disappear after the appearance of Chitinoidella in the uppermost Tithonian. Radiolarians with spherical tests are represented by two morphologies:one of common size, called morphology A, occurs at different levels of both Shal and Kolur Formations, while the larger one, called morphology B, occurs in the Upper Tithonian of the Shal Formation and becomes frequent in the Berriasian – Lower Valanginian beds of the Kolur Formation. The first morphology is relatively frequent in coeval successions of Western Tethyan basins, while the second is rarely reported in the literature. Holothurian sclerites are often abundant in the Lower Berriasian – Lower Valanginian interval, whereas they are rare (or scarcely reported in the literature) in coeval successions of the southern margin of the Western Tethys. Chitinoidella, calpionellids, Saccocoma, protoglobigerinid forams, radiolarian of the morphology A are fossil groups that commonly occur in Tethyan basins. On the contrary, Globochaete and calcispheres were seemingly adapted to local ecological conditions, which were probably different from those of the study area. However, preservation bias for these particular microfossils cannot be excluded in the Kolur section, which is locally affected by faulting.; L’étude de deux coupes correspondant respectivement aux Formations Shal (Callovien – Berriasien inférieur) et Kolur (Berriasien – Valanginien) dans la région du Talesh (Nord-Ouest de l’Iran, marge nord de la Téthys orientale) a permis de caractériser les différentes zones et sous-zones des calpionelles, définies dans des séries des bassins de la Téthys occidentale. Ainsi, les sous-zones à Chitinoidella boneti (base du Tithonien supérieur) et B1 (base de la zone à Calpionella alpina, base du Berriasien inférieur) ont été caractérisées dans la partie supérieure de la Formation Shal. Les sous-zones B3 (sommet de la zone à C. alpina), C1, C2 (zone à Calpionella elliptica), D1, D2, D3 (zone à Calpionellopsis), les zones E (ou à Calpionellites) et F (ou à Tintinnopsella) ont été caractérisées dans la Formation Kolur sur la base d’une riche faune de calpionelles. La zone E a été subdivisée en deux sous-zones : E1 et E2. La première sous-zone est marquée par la persistance du genre Calpionellopsis. Trente espèces de calpionelles ont été décrites. Quinze espèces sont nouvelles, dont 11 du genre Tintinnopsella, deux du genre Remaniella et deux du genre Calpionellites. Parmi les autres microfaunes pélagiques de la limite Jurassique – Crétacé, les Globochaete et les calcisphères (ou microproblématiques), qui sont souvent abondants dans les séries d’âge Jurassique terminal – Crétacé basal des bassins de la Téthys occidentale, sont par contre absents dans la Formation Shal et très rares dans la Formation Kolur. Cette dernière présente pourtant des faciès pélagiques, favorables à la conservation des spécimens de ces deux groupes fossiles. On peut néanmoins signaler, comme dans les séries du Rif externe au Maroc, un pic à Cadosina fusca dans la sous-zone D1 et la présence de Stomiosphaera wanneri dans les niveaux de la zone C. Les Saccocoma, souvent fréquents dans la moitié supérieure de la Formation Shal, disparaissent, comme dans la plupart des séries des bassins de la Téthys occidentale, dans des niveaux assez hauts du Tithonien supérieur, bien après l’apparition de Chitinoidella. Les radiolaires, à coque sphérique, sont représentés par deux morphologies : une de taille normale qualifiée de morphologie A, présente dans les différents niveaux des deux formations étudiées ; une autre de taille plus grande, qualifiée de morphologie B, présente dans les niveaux supérieurs de la Formation Shal (Tithonien supérieur) et devenant fréquente dans les niveaux du Berriasien à Valanginien inférieur de la Formation Kolur. La première morphologie est assez abondante dans les séries de même âge des bassins de la Téthys occidentale ; la seconde y est par contre rarement signalée par les auteurs. Notons que les niveaux du Berriasien inférieur à Valanginien inférieur de la coupe de Kolur contiennent, souvent et en abondance, des sclérites d’holothuries. Les restes de ces organismes sont rares, ou peu signalés dans la littérature, dans les séries de même âge des bassins de la marge sud de la Téthys occidentale. Certains groupes fossiles de part et d’autre de la limite Jurassique – Crétacé sont communs dans les différents bassins du domaine téthysien (Chitinoidella, calpionelles, Saccocoma, protoglobigérines, radiolaires A). Les Globochaete et les calcisphères paraissent par contre mieux adaptés à des conditions écologiques locales qui n’étaient peut-être pas celles de ce secteur de l’Iran, sans exclure les biais de la préservation des microfossiles, notamment dans la coupe de Kolur, localement affectée par des failles.

International audience; An early Berriasian (Berriasella jacobi Zone) ammonite fauna is described for the first time from the Alborz Mountains in northwest Iran. It has been collected from a section located near the village of Shal (Talesh region); in addition to rare phylloceratids, lytoceratids and Neolissoceras, the majority of ammonites belong to the neocomitid subfamily Berriasellinae. With the exception of a new genus and species, Taleshites fuersichi, these taxa are common in European and North African Tethyan successions. Associated calpionellids confirm the early Berriasian age of the ammonite-bearing levels.

Instability structures, synsedimentary faults and turbidites have been studied in the Lower Pliensbachian succession of Saint-Michel-en-Beaumont, belonging to the Taillefer block, an ancient half-graben emplaced during the Liassic Tethyan rifting. Geometrical and mechanical analyses demonstrate that the instability structures occurred thanks to movements along spineless synsedimentary normal faults, when the turbiditic and limestone layers were already case-hardened and partly fractured by tension gashes even when the mudstones were still unlithified. Both the tension gashes and the synsedimentary faults are homogeneous in strike with the major regional faults and are in good agreement with the regional direction of extension for this period. The characters of the turbiditic beds, with erosive base, graded bedding, and incomplete Bouma sequence, are in favour of a seismic origin. Instability structures, spineless synsedimentary faults and turbiditic inflows are thus considered as seismites and interpreted as the result of high seismicity periods including some events with M > 5 in the general extensive ambiance of the Liassic Tethyan rifting. The analysis of the geometrical relationships between all these sedimentary features allows to distinguish the successive stage of occurrence of an instability structure, from the sedimentation of alternating marls and limestones, and sudden turbiditic inflows, then early case-hardening of the turbidites, until the important seismotectonic event generating the spineless normal faults, themselves triggering the fall of indurated blocks and locally the forming of breccias. The Ornon Fault, which constitutes the border of the Taillefer block, 15 km eastward, played a major role during the Liassic sedimentation and may represent the major seismic fault related to the seismites occurrence in the Beaumont basin.

11 pages; International audience; In Dorset (southern U.K.), the Durlston Bay and Lulworth Cove sections expose lowermost Cretaceous coastal marine and non-marine partly evaporitic sediments (the so-called Purbeckian facies). An interval with organic matter (OM)-rich layers is recognized in both sections. This OM-rich interval is 20 m thick in the middle of the Durlston Bay section. Within these beds, a large OM accumulation is recorded, with total organic carbon (TOC) of up to 8.5 wt%. High hydrogen index (HI) values (up to 956 mgHC/gTOC) point to a Type I OM, generally considered as derived from algal-bacterial biomass. This contrasts with the OM present in the underlying and overlying intervals, displaying in general lower TOC and HI values, and consisting of degraded algal-bacterial material with higher proportions of terrestrial OM. This organic-rich accumulation can be interpreted as a period of enhanced primary productivity within coastal lagoonal/lacustrine settings at times of low sea level. It could also correspond to increasingly reducing waters. The OM distribution found in Dorset correlates well with existing long-term palaeoclimatic patterns, i.e. a latest Jurassic (late Tithonian)-Early Cretaceous (early Berriasian) semi-arid climate replaced during the middle-late Berriasian by a more humid climate. This pattern is recorded elsewhere on both margins of the Tethys, indicating a widespread climate change. In Dorset, deposition of OM-rich beds occurs exactly at the transition between these two climate regimes, probably during the first increase in humidity, which led to enhanced freshwater supply into coastal lakes and lagoons. This suggests a direct or indirect climate control on local development of primary productivity and/or anoxia/ dysoxia within restricted shallow coastal water masses. The proposed environmental model links OM production and preservation with a changing, climate-driven, hydrological regime.

Lacustrine and alluvial fan facies from the Lower Mundeck Formation (Barremian ?–Aptian) cropping out in the southern part of the Kribi-Campo sub-basin (Cameroon) have been characterised for their oil potential, using both Rock-Eval pyrolysis and palynofacies analyses. The shaly facies show good potential as oil-prone source rock, with TOC content around 4.4% and some intervals with an optimum potential to yield 45 kg hydrocarbons/t of rock. Along the studied outcrops, these organic-rich facies represent approximately a third of the total thickness. Although the studied samples come out from immature thin organic-rich beds within sand dominated beds, it is reasonable to think that these oil-prone facies increase in thickness and maturity in the offshore area, making this part of the southern margin of Cameroon of special interest for petroleum exploration.

Detrital clay mineralogy is controlled by weathered source rock, climate, transport and deposition that in turn influence the spectral gamma-ray (SGR) response of resultant sediments. Whilst a palaeoclimate signal in clay mineralogy has been established in some ancient successions, the SGR response remains contentious, largely because the data sets have yet to be collected at the same or appropriate vertical scales to allow comparison. In addition, the influence of organic matter on SGR is not always considered. Here, we present clay mineralogical, total organic carbon (TOC) and SGR analyses from the late Jurassic and early Cretaceous of the Wessex Basin, a period of previously documented palaeoclimate change. The aim of this paper is to estimate the sensitivity of SGR as palaeoclimatic tool, SGR and clay mineral data having been collected at the same sample points, making this one of the most rigorous comparison of clay mineral and SGR to date. Overall, the correlation between high thorium/potassium or thorium/uranium and kaolinite associated with a well-established palaeoclimate change shows that elevated thorium may be used as a proxy for humid palaeoweathering, as suggested by few previous studies.

A charophyte assemblage including Latochara tenuicostata (PECK 1937) and Mesochara gr. voluta (PECK 1937) was found in the Lower Tithonian bone-bed 148 of the stratigraphic section at the Pointe de Chassiron, Oléron Island (Charente-Maritime, Southwestern France). This bed, which is well known for its rich and diverse fauna of tetrapods, was deposited in a margino-littoral environment of Purbeckian facies in the Late Jurassic Charente palaeogulf. The occurrence of Latochara at Oléron Island is the most southern location known in the distribution of this genus during the Late Jurassic. This suggests that the boundary between the charophyte Boreal and Tethyan provinces, defined on the basis of this distribution, is not solely determined by latitudinal (i.e. thermal) factors. Ecological factors such as salinity and competition with other charophyte families are hypothesized as alternative explanations.