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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.

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.

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.

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 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.

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.

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.

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.

Resume La repartition des cones d'epandage bioclastiqueen eau profonde etant connue dans le bassin, ainsi que celle des facies urgoniens sur les plates-formes environnantes, nous discutons, exemples de terrain a l'appui, les modalites qui ont permis au sable calcaire d'etre transporte jusqu'au bord du talus et, ensuite, de se resedimenter a plusieurs dizaines de kilometres de la, par des profondeurs atteignant peut-etre le millier de metres. Le schema suivant est propose: transport chenalise dans les vases ≪grossieres≫ de la plate-forme externe par l'intermediaire de courants clairs descendants, stockage temporaire et mise en charge dans les vallees sous-marines et/ou les rigoles incisant le talus, depart des avalanches dans ces couloirs et resedimentation rapide sur des glacis faiblement pentus, dans le domaine des vases pelagiques profondes. Caractere a noter: l'insignifiance des sediments bioclastiques temoins entre la plate-forme et le bassin, en comparaison des volumes de sable calcaire redeposes dans la cuvette.