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Les gisements jurassiens français ou suisses du Crétacé basal (Valanginien ou Hauterivien) recèlent de nombreuses espèces de brachiopodes parmi lesquelles 3 espèces inconnues au Liban : Lamellaerhynchia desori (Loriol in Pictet & Campiche, 1872), Sulcirhynchia valangiensis (Loriol, 1864) et Terebratulina arzierensis (Loriol, 1864). Le site fossilifère de la Formation de Salima à Zeghrine, une localité proche de Bikfaya (Mont Liban), recèle une association constituée de Belothyris pseudojurensis (Leymerie, 1842), Lamellaerhynchia hauteriviensis Burri, 1953, Loriolithyris valdensis (Loriol, 1868), Lor. latifrons (Pictet, 1872), Sellithyris carteroniana (Orbigny, 1847) et Terebratulina biauriculata Orbigny, 1850, toutes également présentes dans les localités jurassiennes. Sur la base de l'étude de son association de brachiopodes, la Formation de Salima est par conséquent attribuée au Valanginien indifférencié. [The Jurassian French or Swiss outcrops of the lowermost Cretaceous (Valanginian or Hauterivian) yield numerous brachiopod species including 3 species: Lamellaerhynchia desori (Loriol in Pictet & Campiche, 1872), Sulcirhynchia valangiensis (Loriol, 1864), and Terebratulina arzierensis (Loriol, 1864), which are not found in Lebanon. The fossiliferous site of the Salima Formation at Zeghrine, a locality close to Bikfaya (Mount Lebanon), yields an assemblage made of Belothyris pseudojurensis (Leymerie, 1842), Lamellaerhynchia hauteriviensis Burri, 1953, Loriolithyris valdensis (Loriol, 1868), Lor. latifrons (Pictet, 1872), Sellithyris carteroniana (Orbigny, 1847), and Terebratulina biauriculata Orbigny, 1850; all are also present in Jurassian localities. On the basis of the study of its brachiopod assemblage, the Salima Formation is therefore ascribed an undifferentiated Valanginian age.]

The discovery in the Cenomanian (early Late Cretaceous) of Southern France of several localities with abundant charcoal has brought to light several angiosperm wood types. This is the oldest angiosperm wood assemblage discovered yet for Europe. Here we analyse this assemblage, with emphasis on features recognized to be of particular palaeoecological and climatic significance for the Cainozoic according to earlier studies and comparing the inferred results to those from other independent lines of evidence (sedimentology, palynology, isotopic geochemistry, etc.). Vessel diameter and distribution, perforation plates, abundance of vascular tracheids and of septate fibres, presence of diffuse axial parenchyma perhaps should not be used as palaeoecological proxies for the Cretaceous because they do not seem to clearly correlate with other lines of evidence that indicate warm tropical conditions. The abundance of fibre-tracheids fits with the other sources of data, but our results are probably biased by preservation problems. On the contrary, the occurrence of growth-rings, porosity, vessel density, occurrence of vessel groups, occurrence of vasicentric tracheids and of some paratracheal to vasicentric and banded axial parenchyma correlate well with other palaeoclimate indicators. These results show that these features can be used for palaeoclimatological inferences during the early Late Cretaceous

The Tre Maroua site in SE France was recently selected by the Berriasian Working Group (BWG) of the International Subcommission on Cretaceous Stratigraphy (ISCS) as the candidate locality for the reference section of the Berriasian Global Boundary Stratotype Point (GSSP). However, on the basis of our preliminary investigation at this site and also from field observations over a larger area, this candidate section is paleogeographically located on a deep-water slope riddled with successive erosional surfaces, stratigraphic hiatuses and breccias. It does not meet at least four of the five "geological requirements for a GSSP". Accordingly, in our opinion, its candidacy must be definitely precluded.

International audience; The Cretaceous marine transgression proceeded through successive steps from the Albian to the Turonian (dated with ammonites). The onlapping wedge begins with coastal transgressiveeregressive short-term sequences on massive, probably fluvial sandstones to be correlated with the very thick continental Lower Cretaceous succession found in the Puerto Cansado well in the Tarfaya sub-basin to the north. A second step, of probable Cenomanian age, reached the Palaeozoic basement. A third, more pronounced step occurred during the earliest Turonian with platy laminated limestone overlain by marlstone bearing pyritized ammonites. At early Turonian peak transgression, a marine connection was possibly established between the Atlantic and the Tethyan margins, between the Anti-Atlas and the Reguibat Shield. From large-scale correlation integrating what occurred along the southwestern shoulder of the Atlas rift, the South Moroccan Atlantic margin may have undergone a short-lived tectonic uplift around the Cenomanian eTuronian boundary.

International audience; Two new sections covering the CenomaniandTuronian transition have been studied at the foot of the Kasserine platform in the northeastern Mellegue basin (Jebels Serj and Bargou). They show, in the uppermost part of the Cenomanian Fahdene Formation, a Pre-Bahloul unit overlain by the well-known Bahloul black shale. Combined foraminiferal and isotope data of the sections complement other published results: (1) extinction of rotaliporids atop of the Pre-Bahloul bed during the build-up of the CenomaniandTuronian Boundary Event (CTBE) d 13 C positive shift, (2) Heterohelix bloom during the deposition of the Bahloul black shale, (3) filament event during d 13 C return to normal values, and (4) first occurrence of Helvetoglobotruncana helvetica during the transition to the marlstone of the Annaba Formation. The Bahloul black shale is here divided into three units, U1 to U3 which are compared with the other sections of the Mellegue basin. The bulk of this paper is a comparison of the two new sections with revisited nearby sections of the Mellegue basin, as well as with those published from the south Tunisian Gafsa trough and Saharan Atlas of Algeria. The comparison suggests that the pre-Bahloul of the Mellegue basin is correlatable with the transgressive fine-grained limestone bed underlying the CTB black shale in the corridors between isolated , keep-up platform carbonates of the Ouled Nail in Algeria, as well as the fine-grained limestone bed overlying upper Cenomanian shallow-water deposits of southern Tunisia. Its sequence stratigraphic significance in the Mellegue basin should therefore be recognized as a deeper-water equivalent of a transgressive systems tract, instead of being interpreted as a lowstand or highstand as it is by other authors. If correct, the inception of the CTBE d 13 C shift would correspond to a transgression over most of Algeria and Tunisia, as observed in the North American Western Interior.

The Kechabta Basin is part of the Tunisian Foreland Basin in front of the Numidian and Tellian nappes. During the Tortonian, this basin records a strong subsidence rate due to flexural process, in front of the nappes. Contrary to previous interpretations, a sedimentological investigation of the thick Tortonian-Early Messinian Kechabta Formation (over 1300 m) reveals that this siliciclastic series corresponds to a complex deltaic shorelines deposit dominated by waves and influenced by tides. This formation is mainly made of a large number of high frequency, mudstone to sandy prograding parasequences representing repeated progradational phases of the coastal wedge. Facies successions within many of the parasequences show normal regressive trends. These parasequences present offshore grey-brown mudstone, followed by transition offshore sandy storm beds alternating with mudstone, then by shoreface sandstones bearing hummocky-cross stratification and wave ripples, then by foreshore facies or tidal flat facies. However, many other parasequences reveal forced regressions during the progradational phases. This evidences that the progradational phases were driven by small, stepped, relative sea-level falls due to a tectonic activity related to the compressive Atlassic phase. This new paleoenvironmental interpretation suggests new elements for the palaeogeographic reconstruction of Northern Tunisia foredeep depozone during the Tortonian-Early Messinian. The base of the Kechabta Formation record the sedimentary response to regional marine transgression of the Mediterranean Sea from the East. This basin was an elongated shallow marine gulf parallel to the thrust front. The fluvio-deltaic systems of the paleo-Medjerda Rivers provided the bulk of the Kechabta siliciclastic sedimentary flux and extensive prograding delta are formed.

Constrained by both foraminifera and isotope data, the Zeitoun and Nahr Ibrahim sections in northern Lebanon record a steady flooding of the Cenomanian carbonate platform during the uppermost Cenomanian-lower Turonian interval. The flooding began just before the inception of the CTBE δ13C positive shift. It is marked by the deposition of finely bedded to laminated, fine-grained limestone overlying platformal carbonates. This scenario is entirely different to what has been published in northern Israel, where repeated emergences are instead recorded during the event. A survey of published data from nearby Middle East countries to North Africa suggests that the CTBE is accompanied on a larger scale, especially along the Syrian Arc, by tectonic disturbances responsible for sequence stratigraphic heterogeneity and palaeogeographic changes. Detailed analysis of available data makes it possible to extract from the sedimentary record four sequence stratigraphic scenarios implying two phases of heterogeneity bounding the event, and responsible for the outphasing of relative sea level changes in some sensitive areas. These disturb a stepped early Cenomanian to early Turonian overall transgressive trend recorded in some large stable areas, often used to support the concept of Mesozoic eustasy. The discussion focuses on the global processes that are possibly involved. The hypothesized tectonic pulse does not explain the CTBE. It is just another set of data to be taken into account in the search for causes.

The first two calcarenite units at the base of the Urgonian limestones on the southern edge of the platform bear different depositional geometries depending on place (Cirque d’Archiane to Montagnette and Rocher de Combau). The lower calcarenite unit (Bi5 of Arnaud H. 1981. De la plate-forme urgonienne au bassin vocontien. Le Barrémo-Bédoulien des Alpes occidentales entre Isère et Buëch (Vercors méridional, Diois oriental et Dévoluy). Géologie Alpine, Grenoble, Mémoire 12: 3. Disponible sur https://tel.archives-ouvertes.fr/tel-00662966/document), is up to 200 m thick and shows three different patterns, in terms of accommodation space, from the western Archiane Cirque to the Montagnette to the east. On the western side of the Cirque, the unit begins on slope fine-grained limestone with thin sigmoïdal offlap geometry, suggesting little available space after a relative sea level fall. It is overlain by thick progradational/aggradational, then purely aggradational calcarenite capped by a coral and rudist-bearing bed. This bed is, therefore, interpreted as a maximum (although moderate) flooding facies. The depositional geometry is different on the eastern side of the Cirque, where a progradational pattern in the lower part of the unit is interrupted by a rotational movement affecting the depositional profile. The deformation promoted aggradation updip and retrogradation downdip as a result of starvation. The inferred growth fault updip (thought to be responsible for the change) began to function earlier at the Montagnette, explaining the huge calcarenite clinoforms found there, filling a deeper saddle created in the depositional profile. The same fault probably was reactivated later during the deposition of the overlying, thinner Bi6-1 unit, which appears at Rocher de Combau with an uncommon tidal facies at the base. A rotational bulge, created by the inferred growth fault, would have protected a small area behind it to spare the local calcarenite deposition from the waves for a while. These two examples show that sequence stratigraphic interpretation may differ from one place to the other, and even show opposite trends due to this kind of disturbance.

The Cap Ferret sand spit is situated along the wave-dominated, tidally modulated Atlantic coast of western France, characterized by a semidiurnal macrotidal range. It displays peculiar dome-like bedforms that can be observed at low tide across the intertidal zone. These bedforms exhibit a wavelength of ca. 1.2 m and an elevation of ca. 30 cm. They occur only when the incident wave heights reach 1.5 a 2 m. The internal stratifications are characterized by swaley-like, sub-planar, oblique-tangential, oblique-tabular, as well as hummocky-like stratifications. The tabular and tangential stratifications comprise prograding oblique sets (defined as foresets and backsets) that almost always show variations in their steepness. Downcutting into the bottomsets of the oblique-tangential stratifications is common. The sets of laminae observed in the bedforms share common characteristics with those formed by supercritical flows in flume experiments of earlier studies. These peculiar bedforms are observed at the surf-swash transition zone where the backwash flow reaches supercritical conditions. This type of flow can explain their internal architecture but not their general dome-like (three-dimensional) morphology. Wave-wave interference induced by the geomorphology (i.e. tidal channel) of the coastal environment is proposed as explanation for the localized formation of such bedforms. This study highlights that the combination of supercritical flows occurring in the surf-swash transition zone and wave-wave interferences can generate dome-like bedforms in intertidal zones. Fil: Romain, Vaucher. Université Claude Bernard Lyon 1; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentina Fil: Pittet, Bernard. Université Claude Bernard Lyon 1; Francia Fil: Humbert, Thomas. Laboratoire D'acoustique de L'universite Du Maine; Francia Fil: Ferry, Serge. Universite Claude Bernard Lyon 1

The Cenomanian–Turonian Boundary Event (CTBE) event is not associated with a transgression on the southern margin of the Subalpine Basin, but with a steady shallowing-up trend beginning in the lower half of the δ 13 C positive shift. The SW–NE Rouaine Fault had a complex role, first in isolating a black shale basin to the west and a large, deep submarine plateau devoid of black shale to the east, then by a strike-slip movement that induced a forced progradation to the north of the southern platform in the eastern compartment. This compressive tectonic reactivation of the southern margin began around the deposition of the local equivalent of the Plenus bed of boreal basins, as shown by correlation supported by both isotope and palaeontological data. Other local data are pieced together to suggest that the whole of SE France underwent a short-lived transpressive tectonic pulse around the Cenomanian–Turonian boundary, probably connected with the early compressive movement of Africa vs. Europe. On a larger scale, other published data suggest that this pulse could be a global one. It is coeval with renewed thrust loading, volcanism and transgression in the North-American Western Interior, local emergences during the event along the eastern Atlantic margin, suggesting a slight tendency to inversion of the margin, and a tilting to the east of the North-Africa plate that could explain the large transgression recorded from Morocco to Tunisia on the Saharan Craton. New isotope and palaeontological (coiling ratio of Muricohedbergella delrioensis ) data from SE France suggest that two coolings of suprabasinal importance occurred just before and during the build-up of the d 13 C shift, including the boreal “Plenus Marls“, especially its middle limestone bed and its SE France equivalent. Regarding the extinction of the genus Thalmaninella and Rotalipora and during the event, neither anoxia nor climate changes can fully explain the palaeontological crisis, given that Rotalipora cushmani crosses the first phase of anoxia without harm, as well as the two coolings, not only in SE France but on a large scale, as shown by the correlation of the published data. This extinction needs alternative explanations as we challenge both anoxia and climate as major causes.

International audience; Several transects made of correlated stratigraphic sections and well logs have been constructed spanning southern Tunisia and the Algerian Sahara (Tinrhert) for comparison with earlier results obtained in the Saharan Atlas. The study is based on fades analysis, sedimentology, biostratigraphy focused on ammonites and foraminifers) as well as whole rock geochemistry (delta C-13). These suggest that the entire northern Sahara Platform underwent marine flooding that commenced just prior to the onset of the global positive delta C-13 shift documented for the Cenomanian-Turonian boundary. This flooding occurred in two phases. The first phase is expressed by the deposition of deeper-water, light-coloured bioturbated mudstones overlying the shallow-water deposits comprising the local Cenomanian successions. But in some places in the Central Sahara (Hassi Messaoud area, Tihemboka Arch) as well as in the Saharan Atlas, shallow-water carbonates kept up locally with the relative sea-level rise to build up isolated carbonate platforms. The topographic lows or saddles between these areas could have been formed through differential accumulation rates. During the second phase, flooding resumed and black shales were deposited over the mudstones in the saddles. The occurrence of black shales in these saddles is limited to the northern edge of the platform (Saharan Atlas of Algeria, Gafsa Trough in southern Tunisia). On the platform, this phase is represented by the same kind of mudstones deposited during the first phase of the flooding (southern Tunisia), or by ammonite-rich chalks in the intra-cratonic basin of the Tinrhert (southern Algeria). Black-shale deposition ceased in the early Turonian. Based on the delta C-13 curve, the latest Cenomanian flooding of the Sahara Platform is roughly coeval with that documented for the US Western Interior. During the first phase of the transgression, that is before the occurrence of the large Whiteinella of the W. archeocretacea Zone in the black shale unit, planktic foraminifers are dominated by small globulose forms of the Hedbergella delrioensis type, associated with Heterohelicidae. Keeled forms (rotaliporids, dicarinellids) are scarce and always very small when present. Perhaps these dwarfed forms were adapted to the restricted environments of the extensive intracratonic seaways crossing the Saharan Platform to the Benoue Trough in Nigeria.

The Middle Oxfordian of the eastern Paris Basin constitutes a remarkable example of the growth and demise of a carbonate platform. Fischer plots, sedimentary and diagenetic features allow the identification of four depositional cycles (S5 to S8) in the Transversarium Zone; they are inserted in a lower frequency cycle of increased/decreased accommodation space (SoIII). The long-term period of accommodation creation occurred during the older S5 and S6 cycles, the maximum accommodation zone being located in the lower part of the S6 cycle. This high accommodation period was tectonically controlled and was coeval with local distensive activity of a Hercynian fault. A major minimum accommodation zone exists during the S8 cycle. At that time, the platform was isolated and presented both a windward and a leeward margin. The growth of the platform was favoured by a warm and arid climate, oligotrophic conditions and reduced siliciclastic input during a highstand in relative sea-level. These palaeoenvironmental features favoured the proliferation of phototrophic organisms producing carbonate material. The death of the platform was generated by a reduction in the carbonate production surface during a lowstand in relative sea-level and by the appearance of mesotrophic conditions induced by the increase in siliciclastic inputs at the beginning of a period with a cooler and more humid climate. In the eastern Paris Basin, during the Middle Oxfordian, the parasequences are ordered and present 'greenhouse' characteristics. In contrast, at the beginning of the S8 cycle, the randomness in the thickness of contiguous parasequences increased. Decreased carbonate production during the lowstand caused by a transition from photozoan to heterozoan benthic communities certainly favoured this randomness and the appearance of catch-down parasequences.

International audience; Outcrops, offshore wells, electric logs and seismic profiles from northern Tunisia provide an opportunity to decipher the Messinian Salinity Crisis in the Strait of Sicily. Messinian deposits (including gypsum beds) near the Tellian Range reveal two successive subaerial erosional surfaces overlain by breccias and marine Zanclean clays, respectively. In the Gulf of Tunis, Messinian thick evaporites (mostly halite) are strongly eroded by a fluvial canyon infilled with Zanclean clays. The first erosional phase is referred to the intra-Messinian tectonic phase and is analogous to that found in Sicily. The second phase corresponds to the Messinian Erosional Surface that postdates the marginal evaporites, to which the entire Sicilian evaporitic series must refer. The Western and Eastern Mediterranean basins were separated during deposition of the central evaporites.

EnglishA series of sections from the Ouled Nail, Hodna and Aures massifs of Algeria have been studied to analyse the palaeogeographic evolution of the eastern part of the Saharan Atlas prior to and after the Cenomanian/Turonian (C/T) boundary event. Three periods are distinguished in the interval studied. During the middle to late Cenomanian, an overall ramp setting prevailed from the Saharan platform to the deeper environments of the Saharan Atlas. The latest Cenomanian and the earliest Turonian was marked by an episode of marked palaeogeographic change. Prior to the deposition of C/T boundary black shales, a rise in sea level occurred. Shallow-water carbonates were locally able to accommodate the sea-level rise. A "keep-up" response created a palaeogeography made up of isolated carbonate platforms separated by saddles, where a 1-20 m thick bed of deeper water mudstones was deposited as the lateral equivalent of the platform carbonates. At a larger scale, these saddles probably acted as corridors that allowed marine communication with the intra-Saharan basins (Tinrhert, Tademait basins). Correlations show that the boundary black shales later filled up the saddles of the Saharan Atlas, and onlapped the carbonate platforms, before the deposition of lower Turonian open marine marls that everywhere blanket the successions. During the early to late Turonian, the palaeogeography again changed to restore a N-S oriented ramp setting, similar to that of the middle Cenomanian. Correlation with the deeper-water facies of nearby northern Tunisia, suggests that the uppermost Cenomanian mudstone immediately underlying the black shale facies in the Saharan Atlas is the lateral equivalent of the uppermost bed of the Fahdene Formation (the so-called "pre-Bahloul") underlying the Bahloul black shale facies in the Tunisian Kalaat Senan reference section. Our platform-to-basin correlations show that the base of this bed is a regional transgressive surface, not a type II sequence boundary as suggested by previous authors. Finally, it is proposed that this mudstone bed correlates with Bed 63 of the Pueblo global reference section in the North American western Interior Basin, which also marks the beginning of the strong C/T boundary transgression. francaisUne douzaine de coupes levees dans les massifs des Ouled Nail, du Hodna et de l'Aures permettent de decrire l'evolution paleogeographique particuliere de ce domaine situe sur la flexure nord-saharienne, au moment de la crise de la limite Cenomanien-Turonien. Trois periodes sont distinguees. Au cours de la premiere (Cenomanien moyen-superieur p.p.), une paleogeographie globalement de rampe s'etablit entre la plate-forme saharienne et le domaine plus profond de l'Atlas saharien. La seconde periode couvre le passage Cenomanien-Turonien (C/T). Elle est marquee par un changement paleogeographique tres net. Juste avant le depot des black shales de la limite C/T, une elevation moderee du niveau marin relatif se produit. Les carbonates de plate-forme sont localement capables d'accommoder cette elevation. Il en resulte une paleogeographie particuliere faite des plates-formes carbonatees isolees, separees par des ensellements ou se depose, en equivalent lateral de facies, une couche de calcaires fins de 15 metres a moins d'un metre d'epaisseur selon les endroits. A plus grande echelle, ces ensellements ont pu constituer des corridors assurant la communication des bassins intra-sahariens de meme âge (Tinrhert, Tademait) avec la Tethys. Nos correlations montrent que les black shales qui terminent cette seconde periode se sont deposes uniquement dans ces ensellements qu'ils remplissent totalement, avant le retour a une sedimentation marneuse generalisee au cours du Turonien inferieur. Au cours de la periode suivante, couvrant le reste du Turonien, s'effectue la restauration d'un profil globalement de rampe orientee sud-nord, avec les carbonates de plate-forme progradant et retrogradant regulierement sur ce profil. Les correlations effectuees avec la coupe de reference de Kalaat-Senan en Tunisie du Nord suggerent que la couche de calcaire fin du Cenomanien terminal de l'Atlas saharien, sous les black shales, et dont l'epaisseur diminue de l'Aures vers le bassin du Mellegue, soit un equivalent lateral du banc calcaire (« pre-Bahloul ») qui surmonte la formation Fahdene et precede l'installation du facies Bahloul en Tunisie. Dans ce cas, la base de cette couche calcaire n'a pas la valeur regionale d'une limite de sequence de type II comme il a ete anciennement propose mais au contraire une valeur de surface de transgression. Nous proposons egalement de correler cette couche calcaire avec le banc 63 de la coupe de reference de Pueblo dans le bassin interieur nord-americain ou ce banc marque egalement le debut de la transgression, apres le depot des shales de Hartland.

International audience; Seven sections, covering the upper Albian to lowermost Turonian, have been correlated from full-marine to continental-dominated deposits across a passive margin, along a transect 425 km long, from the present-day Atlantic coast to the ``Pre-African Trough'' between the Anti-Atlas and the High-Atlas. The thickness of the Cenomanian succession changes from around 500 metres in the fully marine sections to 250 metres in mostly continental facies in the western High-Atlas, about 150 km updip, to a few tens of metres in the Bou Tazoult area. The strata thicken again eastwards into the Pre-African Trough where they can be traced without major facies changes to the Kem Kem embayment and to the Bechar area in Algeria. Over all this eastern area, continental facies are overlain by the fully-marine shallow-water deposits of the Cenomanian-Turonian boundary interval. A first major conclusion is that fluvial aggradation in high-frequency transgressive-regressive sequences is coeval with the seaward-shift of the shoreline, in accordance with the genetic sequence stratigraphic model of GALLOWAY (1989). Both the flatness of the depositional profile and the corresponding very low energy of the marine environment during the transgressions account for the blanket of red continental clays on top of marine facies in updip depositional sequences, which is then preserved under the marine transgressive surface of the next sequence. A second major conclusion is that the high-frequency transgressive-regressive (T-R) sequences do not look like classical parasequences bounded by transgression surfaces. They usually exhibit a surface created by a sea-level fall within the regressive half-cycle. This is interpreted in the following way: regressions did not operate through a regular seaward-shift of the shoreline, but through stepped sea-level falls. The very low slope of the depositional ramp is thought to have enhanced the sequence stratigraphic record of such stepped regressions. Short-term, high-frequency sequences are organized into medium-frequency T-R sequences (seven in the Cenomanian) which show an overall aggrading and slowly retrograding pattern along the whole transect. Comparisons with other basins show that medium-frequency sequences do not fit the third-order depositional sequences described elsewhere, casting doubts about a eustatic mechanism for their deposition.

Porous micritic facies, either primary chalks or resulting from secondary destructive micritization, can constitute important hydrocarbon or water reservoirs. Characterization of reservoir properties and the understanding of factors which controlled the distribution of porosity are of primary interest to evaluate the prospective reserves. Middle and late Oxfordian limestones of the eastern Paris Basin show several horizons with porosities higher than 20%. The porosity is mainly microporous and located either within secondary micritized grains or in the micritic matrix. Using SEM, cathodoluminescence, as well as confocal microscopy, stable oxygen and carbon isotope ratios, and petrophysical measurements, a scenario for the evolution of the micropores is proposed. Lime mudstones to packstones constitute the majority of the high-porosity facies (HPFs). Inner lagoonal deposits are more micritized and thus more porous than grainstones, and facies rich in leiolitic oncoids and echinoid clasts are less impacted by micritization. Micritization was responsible for an increase of the intragranular porosity in most grain types. During both eogenesis and shallow burial, mineralogical stabilization dissolved aragonitic particles and allowed precipitation of calcite rhombs. This process was probably enhanced below surfaces of subaerial exposure. During burial, Ostwald ripening allowed the growth of larger micrite crystals at the expense of smaller ones during early Berriasian and late Aptian recharges of deep aquifers when the northern margin of the basin was exposed. Overgrowths on micrite crystals were more important in intervals strongly affected by chemical compaction, which favored oversaturation of waters with respect to calcite. In low-porosity horizons (LPFs), the dense micritic texture of oncoids and the monocrystalline architecture of echinoid clasts prevented an intense micritization, while the strong chemical compaction enhanced poronecrosis. Telogenetic fracturing created new fluid pathways that favored inputs of meteoric fluid in porous micrite and allowed the continuation of Ostwald ripening during Cenozoic times. As a whole, mesogenetic inputs of waters undersaturated with respect to calcite in deep aquifers during exposure of basin margins are a more efficient process than early subaerial exposure for enhancing aggrading neomorphism and appearance of microporous micrites. Initial mineralogical heterogeneities also impact the intensity of chemical compaction and thus the stratigraphical distribution of microporous limestones.

International audience; Once interpreted as a deep-water canyon infilling and later as some kind of tempestite deposit, the Tithonian breccias of Cause are here reinterpreted as a small lobe deposit, emplaced at the mouth of a gully cutting into a slope between two deep-water terraces in the eastern part of the subalpine basin. The breccias belong to two basic categories: mostly grain-supported and occasionally mud-supported. Spectacular large-scale oblique geometries (apparent lateral accretions) are observed in the grain-supported breccias, both within the infilling of the lower feeder channel and in the updip part of the lobe. Detailed analyses of these geometries show that they correspond to progradational features. Both laterally and in a more distal position on the lobe, these progradational bodies evolve into a pile of unsorted massive breccias, sometimes showing a crude, even stratification. We thus propose a depositional model for the grain-supported breccias, linking the two facies as follows: the deposition of a gravity flow begins at the toe-of-slope (mouth of the tributary gully) by a progradational head which evolves downslope and laterally to a splay of massive or crudely stratified breccia. The internal oblique stratification flattens distally over a distance of a few kilometres. Elementary beds pile up in morphological compensation to build the 100 m thick breccia body of Case. Because the breccias are derived from the gravity-reworking of deep-water nodular carbonates, there is no sand-sized material available in the depositional system, or only a little probably produced through an erosive clast grain diminution process during transport. This explains why the thick breccia beds pass quickly eastward to thin-bedded mud turbidites.

International audience; Upper Cretaceous conglomerates, sandstones and calcarenites outcropping in the Glandage syncline (Les Gas Gorge) belong to two superimposed ``turbidite'' systems, the first being the shortest (about two hundred metres thick, five kilometres wide, and a mere ten kilometres long). Both onlap a SW-NE oriented palaeoslope created by faulting in the latest Turonian on the southern edge of the Vercors carbonate platform. The first system is Coniacian in age, the second probably Campanian. This study deals only with the first system which comprises, in stratigraphic order, classical sandstone turbidites, clast-supported conglomerates, and coarse-grained, cross-bedded, sandy calcarenites. The transition between the last two lithologies is progressive, allowing the mechanisms, responsible for apparent lateral accretions found pervasively in both the conglomerates and the calcarenites, to be understood. Here, cross-bedding is not the result of changes in the direction of accretion in ``lateral bars'' or in oblique infillings of sinuous channels, as is often suggested in other similar deep-water carbonate systems. Each event bed comprises a prograding conglomeratic head plug, blanketed in continuous sedimentation by forward spreading bioclastic calcarenites. The superimposition of such mixed beds gives rise to a low-angle cross-stratification, an unusual feature for a system interpreted as a base-of-slope apron. Conglomerates were probably deposited through a granular flow mechanism at a strong hydraulic jump at the base of the slope. Associated calcarenites show supercritical flow features. The undulating transverse architecture of its large head onlapping the paleoslope suggests it is a multi-apex apron. The sandstone-conglomerate-calcarenite succession of the depositional sequence is interpreted as overall transgressive after the late Turonian tectonic phase that led to the exposure of the Vercors carbonate platform updip.

Corals from the Barremian of southern France (dept. Ardeche and Drome) are described. The rather small fauna of colonial corals encompasses 23 species belonging to 18 genera of both Hexa- and Octocorals. The assemblages from the lower as well as upper Barremian show stratigraphic relationships to those of the Hauterivian and Aptian of the Tethys and the Caribbean province.

Palynological studies realized from a borehole drilled on the site of ANDRA (Agence Nationale pour la gestion des Dechets RAdioactifs; Aube Centre near Soulaines, Paris Basin, France) show a sedimentary discontinuity between, on one hand, the Argiles a Plicatules (lower Aptian in age) and Argiles Ostreennes (Lower Barremian/Upper Barremian in age) and, on the other hand, between these same Argiles Ostreennes and the Calcaire a Spatangues (Lower Hauterivian). These conclusions argue against the chronostratigraphical subdivision recently proposed on the basis of sequence stratigraphical and sedimentological interpretations.

The Oxfordian carbonate platform of Lorraine: evidences for an opening toward the Germanic Sea. The study of sedimentary facies in the quarry of Dompcevrin (Middle Oxfordian) located northwestward of St-Mihiel (Meuse department) provides evidences of high-energy depositional conditions. The occurrence of beaches associated with hurricane coral breccias containing megaclasts is characteristic of platform edge environments. The open sea was located northeastward, in the direction of Germany, as it is indicated by the direction of progradation of beaches. It is concluded that the Oxfordian carbonate platform of Lorraine was opened to the northeast toward the Germanic Sea during the Middle Oxfordian. To cite this article

Resume Le cout medicamenteux evite par la gratuite des traitements pour essai clinique a ete estime sur la base du cout du medicament qui aurait ete utilise sans l’essai. Sur 56 essais evaluables en 2000, le cout medicamenteux evite estime pour seulement 46 essais etait compris entre 585 492 et 603 674 €. Pour dix essais, aucune alternative therapeutique valide n’etait disponible. Il existait une tres grande variabilite du cout evite estime par essai ou par patient (CV : 120–520 %). Deux indications representaient 94 % du cout medicamenteux evite total (sclerose en plaques et deficit en hormone de croissance). Cette gratuite n’a pas profite a l’hopital tres implique dans l’essai (

For a better understanding of siliciclastic shelf environments, correlation between sequence stratigraphy and organic geochemistry is used. Our study is focused on the Cretaceous deposits of Marcoule (Gard, France), particularly on a close-packed siltites layer (200-400 m thick), which is well characterized as a marine flooding facies of a single trangressive-regressive cycle. During the Uppermost Albian and the Lower Cenomanian, the stratigraphic data indicate a change in the depositional environment from offshore to shoreface. Organic geochemistry is used in order to characterize origin and variability of the organic matter in relation to the stratigraphic data. The study is carried out on core samples from 2 drill holes (MAR 203 and MAR 501). Analyses of the aliphatic and aromatic hydrocarbons were performed using GC-MS and focused on biomarker distributions. The biomarkers indicate a contribution of mixed terrestrial and marine organic matter. The changes in molecular signatures are related to variations in the source of organic matter (marine versus terrestrial), preservation conditions (largely influenced by clay and early diagenesis), environmental oxidation-reduction and acidic conditions as well as bioturbation. Various environmental zones, characterized by different molecular signatures, can be distinguished. Resin derived biomarkers can be assigned to higher plant material input and may reflect the evolution and diversity of Gymnospermae versus Angiospermae during the transgressive/regressive cycle. The relative sea-level variations are clearly correlated with the nature and the preservation of the organic matter. For example, the Pr/Ph and Pr/n-C 17 ratios as well as the regular steranes distributions underline the maximum flooding surface evidenced by other studies. We observe a good correlation between the organic data and sequence stratigraphy: changes in geochemical signatures reflect the 3rd order depositional cycles.

Results of a paleomagnetic, rock magnetic, geochemical, and petrographic study on Jurassic and Cretaceous carbonates in the Vocontian trough support a hypothesized connection between burial diagenetic alteration of smectite and the widespread occurrence of a chemical remanent magnetization (CRM) carried by magnetite. Where smectite has altered to other clay minerals, limestones are characterized by a prefolding, secondary, normal polarity magnetization throughout the basin. The magnetization is interpreted to be a CRM based on low burial depths which cannot cause thermoviscous resetting. Where significant smectite is still present, the CRM is absent/weakly developed, and where the clays show no evidence for burial alteration, the units are characterized by a primary magnetization. CRM intensity also varies with the amount of smectite and burial. Isothermal, anhysteretic, and natural remanent magnetization intensities increase where smectite has altered, both stratigraphically and geographically. This is interpreted to indicate magnetite authigenesis associated with clay diagenesis. Superparamagnetic magnetite is more dominant in highly altered units based on the results of low-temperature experiments. All sections away from the Alps have 87Sr/86Sr values that are similar to coeval seawater, and stable isotopes of carbon and oxygen show no sign of alteration. Orogenic-type fluids therefore are not a likely agent of remagnetization. Near the Alps the rocks are characterized by an additional reversed polarity component which is interpreted to reflect acquisition of the CRM through a reversal. A postfolding magnetization is also present there and strontium isotopic ratios are higher than elsewhere in the basin and might indicate some alteration by orogenic-type fluids. We conclude that burial diagenesis of smectite is the likely cause for the development of the widespread CRM in the Vocontian trough and that this mechanism might explain widespread chemical remagnetization elsewhere.

This contribution is focused on a high-resolution cyclostratigraphic investigation by means of an integrated study on the deposits on Zakynthos island (Ionian sea) within the Olduvai polarity subchron (from 1.95 to 1.77 Ma). Accurate palaeomagnetic study has been carried out to specify the precise position of the Olduvai subchron in the Zakynthos city series, named “Citadel” section. New detailed lithological observations have pointed out the presence of turbiditic and laminated facies within clay deposits. Layers corresponding to the Olduvai subchron have been studied in detail for pollen analysis and CaCO 3 content in order to evidence responses to the glacial/interglacial cycles. Four climatic cycles have been recognized by pollen and CaCO 3 analyses. In order to achieve a correct correlation with the isotopic stages, the δ 18 O measurements of the Zakynthos's foraminifer Globigerinoides ruber have been provided; they reveal the Artemisia expansions (e.g. steppes) to be contemporaneous with interglacial phases. This behaviour does not conform to the previously evidenced responses of plant associations (especially Artemisia ) to the glacial cycles in the western Mediterranean. Hence, the “west Mediterranean model” cannot be upheld for the whole Mediterranean domain.

A recent detailed analysis of southeastern France upper Cretaceous series has evidenced that Cenomanian-Turonian and Turonian-Coniacian boundaries are marked by quick and large amplitude relative sea level changes. Comparisons with other sections in different worldwide basins are coincident with the observations pointed out in southeast France. We establish: (1) high-frequency synchronous events in different geodynamic settings, (2) the superposition of various hierarchically eustatic cycles i.e. the superimposition of high-frequency oscillations on a third-order trend. Two possible mechanisms responsible of these observations are emphasized and discussed: glacio-eustasy versus high-frequency tectonics.

The negative conduction effect of quinidine on each of the successive phases of the ventricular depolarization was investigated using an original noninvasive method: the spatial velocity electrocardio

International audience; The dynamics of depositional environments and the spatial deformation of drainage networks in foreland basins reflect the tectonic and erosional dynamics associated with the development of mountain belts. The spatial and temporal organization of the Eocene–Oligocene (40–25 Ma) sedimentation in the external part of the South Alpine Foreland Basin of France was reconstructed using an integrated cartographic, sedimentological and petrographic analysis of the Tertiary sedimentary successions. The depositional geometries and variations in facies and thickness of the Palaeogene Nummulitic succession, as well as the observed flow directions in various continental and marine sediments, suggest that the Barrême, Blieux and Taulanne synclines were present as palaeovalleys since the Eocene. The sedimentological analysis of the Nummulitic succession allows the identification of three depositional sequences separated by transgressive surfaces that are recognized in the Barrême, Blieux and Taulanne synclines. Correlation of these sequences between the three synclines suggests that these palaeovalleys were connected by a local valley network that recorded the same sea-level fluctuations during the marine Nummulitic sedimentation. The palaeovalley network was structurally controlled by the east–west axes of the Blieux and Taulanne synclines and the north–south axis of the Barrême syncline formed during the " Pyrenean–Provençal " (Late Cretaceous–Middle Eocene) shortening and the first stage of the Alpine history (Middle Eocene) respectively. Later on, the westward " Alpine " compression (since the Early Oligocene) induced local depocenter migration and reversal in flow direction. However, compared to the modern river pattern, the palaeovalley orientation highlights a geometrical stability since their formation (about 40 Ma), suggesting a long-term stability of the early structures in the foreland basin. This constancy can be explained by the location of the study area in a piggy-back basin transported at the top of the Provençal thrust sheet that facilitated the preservation of the overall axis orientation of the palaeovalleys.

International audience; A level with fern stumps was discovered in the Aptian Douiret Formation, South-Tunisia. These stumps are preserved as external moulds or casts, without any preservation of anatomical structures. These stumps are considered to be affiliated with the numerous fossil plants assigned to the fern genera Alstaettia and Piazopteris that are widely distributed in coeval strata from the same region, either as leaf imprints or as permineralized remains. The record of in situ fossil forests for the Southern Hemisphere reveals that their systematic components are different, i.e. mainly corystosperms and/or conifers, and rarely under tidal influence. The way this fern grove settled in a margino-littoral environment is discussed

International audience; Detailed correlations across Tithonian carbonate breccia deposits in the Drome River area (northern part of the so-called "Vocontian Through") suggest the depositional system was that of an elongated deep-water lobe, up to 70 km long and 20 to 30 km wide, for a thickness reaching 200 m. The Drome lobe, as it is now called, is mainly made of slope to basinal mudstones breccias with minor platform components, interpreted as debris flow and mud flow deposits, associated with slump deposits. It is basically a base-of-slope system, whose elongated depositional area implies it was a "point-sourced" gravity system, thus perhaps connected to a small canyon cut onto the western slope of the basin. But the mostly mudstone material of the breccias also suggests that the walls of this inferred canyon were the main supplier of the lobe, not the carbonate platform proper. The updip part of the lobe has a complex internal geometry as the deposition of breccia bed packages is interrupted by scourings locally 50 m-deep, indicating maybe a canyon mouth environment. The middle part of the lobe is dominated by pure vertical aggradation of breccia beds with minor intervening erosion. In the downdip part of the system a morphological compensation mechanism occurs as breccia beds tend to spread laterally. A huge slump carrying large mudstone olistoliths ends the breccia deposition at the beginning of the Berriasian. This megaslump deposit was mostly emplaced on the right side of the breccia lobe supporting the idea of a depositional relief. Our observations thus show that previous interpretations as a submarine canyon infilling or as shallow-water breccias formed in-situ by cyclic loading under attenuating hurricane waves approaching the platform are not consistent with our observations. The internal geometry of the system studied brings new data about a poorly-studied kind of "turbidite" systems that of deep-water carbonate breccias

The aim of this study was to assess the pharmacokinetics of methohexital (ME) in major vascular surgery (VASC) and to compare these data with the pharmacokinetics of ME during hypothermic cardiopulmonary bypass (HCPB) (temperature: 28°C) and normothermic cardiopulmonary bypass (NCPB) (temperature: 37°C). An ME bolus (2 mg/kg) was administered to 8 VASC patients at the start of surgery and to 11 HCPB patients and 11 NCPB patients at the start of cardiopulmonary bypass (CPB). Twenty-one arterial blood samples were withdrawn over the following 24 hours for ME assays. All of the patients were given similar anesthesia (fentanyl, diazepam) and muscle relaxation (pancuronium). In the VASC group, ME total body clearance (TBC) was 6 ± 2 mL/kg/min (mean ± SD), which is less than in previous studies. When comparing HCPB and NCPB groups, elimination half-life ( T 1 2 ), TBC, volume of distribution (VD), area under the curve (AUC), and mean residence time (MRT) were similar. When comparing VASC and CPB patients, TBC and VD were greater in CPB patients than in VASC patients; thus, T 1 2 (equal to 0.693 × VD/TBC) was similar. AUC was smaller in CPB patients because of hemodilution, but MRT was similar. It is concluded that ME clearance is lower in patients undergoing major vascular surgery than in healthy patients. The temperature and the duration of CPB do not seem to substantially influence the pharmacokinetics of ME when a bolus is administered. Parameters such as AUC, TBC, and VD appear modified by hemodilution during CPB; however, T 1 2 and MRT, which allow comparisons between CPB and non-CPB patients, were similar in these patients.

International audience; Correlations of four sections, constrained by stable isotope stratigraphy and micropalaeontology, along a 80 km-long, E/W-oriented transect from the western High-Atlas to the present-day coast (Taghazoute), show that the Cenomanian Turonian boundary event (CTBE) occurred within shallow-water, oyster-bearing limestones and marls, and not in the overlying black shale. The age of the laminated shale is early Turonian as the planktonic marker Helvetoglobotruncana helvetica is found from its first centimetres upward. The underlying deposits hosting the CTBE event are bounded by two unconformities interpreted as emersion surfaces, and represent the strongest seawardshifts of facies in the local Cenomanian sedimentary wedge. The delta(13)C anomaly is only recorded in the coastal Taghazoute section, not in other sections landward, meaning that the CUBE occurred here during a short transgressive phase within an overall regressive trend. The lower Turonian black shale of the Taghazoute section is transgressive onto the second unconformity and pass landward to white, evenly laminated, chert-bearing mudstones, then to bioturbated mudstones in the easternmost sections of the transect (western High-Atlas)

The Mediterranean Messinian Salinity Crisis, Hsu et al. (1973) has two main expressions, 1/ very deep subaerial canyons incision on the the hinterland and along basin margins, 2/ deposition of marginal and abyssal evaporites in the basins. Boths are well known everywhere around Mediterranean Sea, but surprisingly the occurence of canyons is poorly documented along North African margin except in Egypt where the Nile canyon is well known from onshore, to offshore, since a long time, Chumakov (1973), Barber (1981), Dalla et al. (1997). More recently messinian canyons have been reported: –In Algeria with the Algiers complex, Rubino et al. (2005),–Offshore and onshore Tunisia, El Euch-El Koundi et al. (2008)–In offshore Libya, Barr et Walker (1978), Ryan & Cita (1978), or onshore in Sirte and Kufrah basins, Grifin (2002), Rubino et al. (2005), Nicolai (2008), Drake et al. (2008), Paillou et al. (2008).–Evidences have been also reported from Morroco, Loget. (2002).

Resume L'etude qualitative et quantitative de plus de 12000 ammonites recoltees sur la coupe continue a sedimentationpelagique de La Charce (Drome) est comparee avec les informations provenant d'autres series d'Europe occidentale et integree dans une analyse sequentielle a l'echelle du bassin subalpin. Elle permet de suivre les diverses etapes du renouvellement principal qui coincide avec la fin du cortege de bas niveau marin du sommet de la zone a Trinodosum et avec le cortege transgressif suivant, c'est-a-dire avant le maximum d'inondation de l'Hauterivien basal. Nous insistons sur le facteur migratoire sous dependance climatique pour expliquer ces transformations qui s'enracinent dans la fin du cortege de bas niveau marin mais ne se manifestent pleinement que dans le cortege transgressif. Plusieurs horizons biostratigraphiques nouveaux sont individualises dans le Valanginien superieur.

Resume Les couches calcaires pelagiques du Tithonique superieur-Berriasien d'Angles ont ete etudiees par le moyen des calpionelles, afin de completer l'etude biostratigraphique d'une coupe de reference du Cretace inferieur qui comprend par ailleurs le stratotype du Barremien et l'hypostratotype mesogeen du Valanginien. Quelques petits slumps sont presents dans ces couches basales mais leur tres faible epaisseur ne laissait pas presager l'ampleur des lacunes que nous mettons en evidence: une au Tithonique superieur, l'autre couvrant tout le Berriasien moyen et la moitie du Berriasien inferieur. Celles-ci sont sans doute dues en totalite a des phenomenes de glissements sous-marins, y compris la lacune partielle du Tithonique superieur qui n'est pas soulignee par des couches glissees; la surface d'erosion est scellee par des calcaires pelagiques fins.

International audience; Pollen records, marine faunal associations and stable isotope compositions of sediments from Rhodes, Greece, have been determined to track environmental changes in the eastern Mediterranean during the Early and Middle Pleistocene. A detailed chronostratigraphic curve, based on magnetostratigraphic data, was obtained by correlating pollen spectra with the Mediterranean oxygen isotopic curve of Ocean Drilling Program Site 975. Five sedimentary sequences that correspond to marine oxygen isotope stage (MIS) 31–27 and to MIS 20–17 have been investigated in the confined Tsampika microbasin. High-amplitude Pinus variations confirm glacio-eustatic changes deduced from changes in marine faunal associations and sedimentary depositional environments. Reflecting climatic cycles identified in the marine carbonate oxygen isotope record, eight vegetation successions (characterized by the dominance first of mesothermic elements, then of mid- and high-altitude elements with Pinus, and ending with maxima in herb and steppe elements) have been documented. Most of them were probably driven by changes in insolation occurring in high northern latitudes (obliquity impact) during the late Early Pleistocene and early Middle Pleistocene.

International audience; In the present study, the difficulty which lies in the identification of sea-level fall discontinuities in deep depositional environments led the authors to use the transgressive surfaces (i.e. the most noticeable surfaces in the present case) to determine depositional cycles. Four (3rd order?) Lower and Middle Oxfordian cycles were identified (S1, S2, S3, and S4) in the Eastern Paris Basin. These four cycles can be organised into two lower frequency cycles (So I and So II) which comprise the S1, S2 and the S3, S4 cycles respectively. During the time intervals of the S1, S2, and S3 cycles, sedimentation occurred along a southward dipping carbonate-siliciclastic ramp, prograding from the northern Ardennes area. The S4 cycle shows the development of a reefal distally steepened ramp which subsequently evolved into a flat-topped platform as a result of the compensation infill of the available accommodation space by the carbonate production during a climatic warming, in this case reef growth. Isopach and facies maps suggest synsedimentary activities of hercynian faults coevals with the floodings of the So I and So II cycles. One of these events generated a diachronism of the maximum flooding (Plicatilis Zone) during the So II cycle between the northwestern and southeastern parts of the studied area. The depositional patterns found in the Eastern Paris Basin and the Swiss Jura show great similarities for the Early–Middle Oxfordian. Both regions were probably connected and recorded the same tectonosedimentary evolution. In contrast a tectonic control certainly generated differences between the sequence-stratigraphic framework of the Eastern Paris Basin and the eustatic chart.

International audience; Oxfordian reefal episodes of Lorraine and Burgundy have a long time been considered as contemporaneous. Biostratigraphic data and sequential evolutions peculiar to each region indicate their structural autonomy during Oxfordian times. A northsouth- oriented well-logging transect shows that, during the Middle Oxfordian, a shallow reefal platform developed in Lorraine while thin deeper deposits occurred in Burgundy. In spite of their different ages, reefal episodes of Middle Oxfordian in Lorraine and Upper Oxfordian in Burgundy exhibit a broadly similar vertical evolution of coral communities. During the Late Oxfordian, the contemporaneous occurrence of a diversified assemblage in the Burgundy region, a colder coral assemblage characterized by eurytopic genera and the decrease in seawater isotopic temperatures in Lorraine can be explained by a shift in trophic conditions, a climatic change related to structural rearrangements in this strategic place and a modification of oceanic circulations between the arctic and the Tethyan regions.

International audience; Middle to Upper Oxfordian reefs of a shallow marine carbonate platform located in northeastern France show important facies changes in conjunction with terri-geneous contents. The Pagny-sur-Meuse section shows coral-microbialite reefs that developed both in pure car-bonate limestones and in mixed carbonate-siliciclastic deposits. Phototrophic coral associations dominated in pure carbonate environments, whereas a mixed photo-trophic/heterotrophic coral fauna occurred in more sili-ciclastic settings. Microbialites occur in pure carbonate facies but are more abundant in mixed carbonate-silici-clastic settings. Reefs seem to have lived through periods favourable for intense coral growth that was contempo-raneous with a first microbialitic layer and periods more favourable for large microbialitic development (second microbialitic layer). The first microbialitic crust probably developed within the reef body and thus appears to be controlled by autogenic factors. The second generation of microbialites tended to develop over the entire reef surface and was probably mainly controlled by allogenic factors. Variations in terrigeneous input and nutrient content, rather related to climatic conditions than to water depth and accumulation rate, were major factors controlling development of reefs and their taxonomic composition .

Malartre Fabrice, Ferry Serge, Grosheny D., Philip Jean, Rubino Jean-Loup, Mathy Arnaud. Faciès analysis of a tidally-influenced calcarenitic formation : The Mornas Limestones (Coniacian, South-East France). In: Géologie Méditerranéenne. Tome 21, numéro 3-4, 1994. Perimediterranean carbonate platforms. First International Meeting. Marseille – France (5-8 septembre 1994) sous la direction de Jean-Pierre Masse. pp. 117-120.

Resume Au cours des dernieres annees, plusieurs gisements de Bryozoaires barremiens et aptiens ont ete decouverts dans le Sud-Est de la France. Ces gisements ont fait l'objet d'etudes stratigraphiques et sedimentologiques recentes dont les apports les plus importants en ce qui concerne la biostratigraphie et la paleoecologie des Bryozoaires, sont exposes ici par les auteurs des decouvertes. Les Bryozoaires barremiens du Sud-Est sont les premiers de cet age a etre decrits, la faunede l'Ardeche est la meilleure que l'on connaisse actuellement. L'etude de cette faune barremienne permet de preciser les relations entre les faunes neocomienne et aptienne, seules connues jusqu'alors et nettement differentes l'une de l'autre. Le renouvellement de la faune se fait a l'Hauterivien superieur ou au Barremien basal, avec l'apparition brutale de deux sous-ordres: les Pachystega (genre Siphodictyum ) et les Salpingina (Melicertites, Cea) . Ce changement rapide ne peut etre du qu'a une migration dont les causes (changement paleogeographique ou climatique) ne peuvent etre actuellement elucidees. Les Bryozoaires de la «Couche superieure a Orbitolines (Aptien du Vercors) sont particulierementinteressants au point de vue paleoecologique. On assiste en effet a l'evolution de la faune, en partie epiphyte et en partie de substrats durs, vers une faune strictement epiphyte au fur et a mesure de l'ennoyage des parois rocheuses par un sediment fin.

Resume Dans le S-E de la France, l'intervalle Valanginien-Aptien inferieur est caracterise par le grand developpement des plates-formes carbonatees dites urgoniennes (massifs subalpins septentrionaux, Ardeche et Gard, Provence) qui ceinturent le bassin vocontien, appendice occidental de la mer alpine profonde. Leur histoire, retracee a l'aide de cartes de facies, se resume en une colonisation progressive, quoique discontinue, d'aires hemipelagiques perivocontiennes a partir de plusieurs foyers: deux d'entre eux existaient deja des le Berriasien en Basse-Provence, d'une part, dans le Bas-Dauphine et le Jura d'autre part. Le premier a persiste durant tout le Cretace inferieur, le second avait disparu a l'Hauterivien. Au Barremien inferieur, des hauts-fonds bioclastiques se mettent en place dans le Vercors meridional et en Ardeche; ils amorcent une vaste extension des plates-formes carbonatees aux depens des facies hemipelagiques du pourtour vocontien. Cette evolution, regressive dans son ensemble, dependit sans doute en partie du jeu synsedimentaire d'accidents du socle; elle fut coupee d'arrets et de retour en arriere momentanes. Trois des discontinuites correspondantes se rencontrent dans tout le S-E de la France et permettent ainsi des correlations d'evenements. A l'Aptien inferieur, les calcaires a rudistes (Urgonien s.str.) presentent leur maximum d'extension; leur disparition, localement a l'Aptien basal (sillon sud-provencal), plus generalement au Bedoulien superieur, se fait brutalement sous des depots transgressifs marneux. Avec l'effacement des plates-formes cesse egalement le detritisme carbonate qu'elles ont alimente sur leur pourtour externe, en particulier les coulees bioclastiques qui parvinrent par gravite des le Barremien inferieur jusqu'au centre du bassin vocontien. Succedant a des marnes fini-bedouliennes et gargasiennes, une recurrence plus modeste du regime de plate-forme se produit ensuite au Clansayesien, avec des calcaires bioclastiques et se poursuit localement (Provence) jusqu'a l'Albien inferieur.

Resume Les series barremo-urgoniennes du Sud del'Ardeche et du Nord du Gard s'apparentent plus avec celles du Vercors et du Devoluy qu'avec celles de la Provence. Elles temoignent d'une evolution paleogeographique en deux temps: 1) Au Barremien inferieur, individualisation etextension a partir de deux hauts-founds (Serre de Tourre et Dent de Rez), des facies pre-urgoniens biodetritiques. 2) Au Barremien superieur - Bedoulien, installationet evolution de la plate forme urgonienne. A la fin de cette periode, les facies a rudistes occupent la presque totalite du territoire. Ils disparaissent ensuite sous des depots bedouliens transgressifs marneux ou marno-greseux.

Synthetic human pancreatic tumor GH-releasing hormone (hpGRH l-44-NH2) was given by iv bolus injection to 10 normal men at doses of 75, 150, 300, and 600 μg. At all doses the plasma GH responses were similar in an individual subject. Among subjects, however, the responses were significantly different, with peak GH concentrations ranging between 9.0 μg/liter and 54.9 μg/liter. The GH released in response to GRH was bioactive in the Nb2 lymphoma cell multiplication assay. The circulating GH 30 and 60 min after GRH was detected in 3 molecular forms corresponding to little, big, and big-big GH. These forms averaged 50%, 30%, and 20% of the total immunoreactive GH, respectively. The mean rise of plasma somatomedin-C, from 1.86 U/ml to 2.21 U/ml 24 h after GRH, was not statistically significant. A small but statistically significant GRH dose-dependent rise in plasma PRL (mean PRL concentrations 10 min after 600 fig GRH, 11.13 μg/liter occurred consistently after GRH injection. The evidence that the GH ...

Resume Dans le Sud de la France les regions aquitanopyreneenne et delphino-provencale ont connu durant l'intervalle Barremien - Albien plusieurs episodes de depots urgoniens dont il est rappele les traits paleoceanographiques et stratigraphiques principaux. L'histoire des plates-formes carbonatees est retracee et leur contexte paleogeographique precise. On en deduit les grandes etapes de l'evolution des calcaires urgoniens et la specificite des diverses regions concernees. Le role des deformations tectoniques ulterieures dans la reconstitution paleogeographique et l'influence du bâti structural antecretace sur la repartition des depots sont discutes.