La transgression thanétienne (Paléocène supérieur) dans l’Aurès occidental (Algérie), d’après les associations de Foraminifères de la coupe d’El Kantara

In the W-Aures (Algeria), the El Kantara pass displays about 50 m of Red Marls overlying the Maastrichtian limestones with Laffitteina. The Red Marls are, in their turn, overlain by the Thanetian marly limestones of the river El Haï. The micropaleontological inventory of these Red Marls establishes the co-occurrence of subaerian (Microcodium = Paronipora), fresh-water (Charophyta) and marine microfossils (Foraminifers). The stratigraphical significance of these microfossils is discussed. The upper part of the Red Marls, yielding abundant Valvulina and scarce Glomalveolina, is of Thanetian age. The age of the lower part is less established, but the occurrence of Microcodium suggests a Thanetian age too. Located at the margin of the northern opening of the trans-Saharan epeiric sea, the El Kantara section establishes a Thanetian age for the beginning of the Paleocene transgression. Danian deposits are missing, in spite of the absence of an obvious hiatus on the field. After general emersion during the early Paleocene, the Thanetian transgression starts with the set up of lakes at the depositional area of the Red Marls. Marine influences, limited at first, become gradually prevailing, and end with the deposition of neritic marly limestones of river El Haï.     

Encrusting micro-organisms and microbial structures in Upper Jurassic limestones from the Southern Carpathians (Romania)

Late Jurassic–Early Cretaceous ?tramberk-type reef limestones are known from some parts of the Southern Carpathians in Romania. The Upper Jurassic deposits mainly consist of massif reef limestones including a variety of microbialites associated with micro-encrusters. They played an important role in the formation and evolution of the reef frameworks and thus are of significant importance for deciphering the depositional environments. For our study, the most important encrusting organisms are Crescentiella morronensis, Koskinobullina socialis, Lithocodium aggregatum, Bacinella-type structures, Radiomura cautica, Perturbatacrusta leini, Coscinophragma sp., and crust-forming coralline sponges such as Calcistella. Based on microscopic observations, microbial contribution to reef construction is documented by the abundance of dense micrite, laminate structures, clotted, thrombolithic or peloidal microfabrics, constructive micritic cortices, biogenic encrustations and cement crusts, as well as by other types of microbial structures and crusts. Most of the investigated carbonate deposits can be classified as “coral-microbial-microencruster boundstones” which are characteristic for the Intra-Tethyan domain. Their paleogeographical significance is indicated by the presence of many features comparable with carbonate deposits of rimmed platform systems from the Northern Calcareous Alps or Central Apennines. Based on the distribution of the facies and facies associations within the carbonate sequences under study we can distinguish slope and external shelf margin environments. The microbial crusts, the encrusting micro-organisms, and in some cases the syndepositional cements have stabilized and bound the carbonates of the slope facies types. Subsequently, the stable substrate favored the installation of coral-microbial bioconstruction levels.     

Palaeogeography and geodynamic evolution of the Gosau Group of the Northern Calcareous Alps (Late Cretaceous, Eastern Alps, Austria)

The sedimentation of the Late Cretaceous Gosau Group of the Northern Calcareous Alps records the complex geodynamic evolution of the northern part of the Austroalpine microplate. The tectonically controlled sedimentation and facies distribution were mainly governed by the oblique subduction of the Pennic-Ligurian ocean below the Austroalpine margin. Most of the Gosau successions comprise two distinct sedimentary complexes. The Lower Gosau Subgroup (upper Turonian-Campanian) is characterized by terrestrial to shallow-marine facies associations: alluvial fan and fan delta deposits, shallow-marine sandstones and sandy limestones, and storm-influenced nearshore and shelf deposits. During the early Santonian sea-level highstand, a great part of the Northern Calcareous Alps was covered by a shallow shelf sea. Palaeotransport directions point to source areas situated both to the north and to the south of the Northern Calcareous Alps.

The Upper Gosau Subgroup (upper Santonian-Eocene) comprises deep-water hemipelagic and turbiditic deposits. Rapid subsidence into bathyal to abyssal depths started diachronously from the northwest (Santonian) to the southeast (Maastrichtian) after a short phase of deformation and erosion. Abyssal deposits in the northern parts of the Northern Calcareus Alps and north-directed palaeotransport indicate a tilting of the slope towards the north. This subsidence pulse is attributed to an event of subcrustal tectonic erosion, probably triggered by the subduction of a topographic high of the South Penninic ocean. The relationships of the Gosau Group of the Austroalpine unit to Late Cretaceous deposits of the Carpathians and Southern Alps are discussed in the framework of a plate tectonic model.     

Biostratigraphie des brachiopodes et âge carixien (Pliensbachien inférieur) des calcaires à grands bivalves en Algérie occidentale

Recent researches on the Lower Jurassic of Western Algeria allow to establish a lithostratigraphic standard correlating the different members and formations developed in the Ouarsenis and Tlemcen Mountains, the Oran High Plains, the Nador and Ksour Mountains. The position of the large bivalve limestones (= Lithiotis limestones) is well established in the different lithologic successions. This facies is widespread in Western Algeria where it is interbedded with brachiopod marker beds, indicating short periods of maximum flooding. The large number of collected brachiopods are distributed into four “faunas” (assemblages) ranging from the Late Sinemurian (= Lotharingian) to the Early Pliensbachian (= Carixian). These faunas have been dated by the age of the species that they have in common with the NW european and western tethyan provinces. These chronological data are confirmed by rare ammonites. All these results evidence the age of the large bivalve facies in Western Algeria. They are contained in the Middle to Late Carixian (Demonense and Dilectum Zones). This datation is in conformity with that known from the Eastern High-Atlas (Bou Dahar). Consequently, the large bivalves cannot be considered as “markers for the unique Domerian” as it has been too often asserted. The palaeontological part of our study shows that the multicostate Zeilleriids (several Tauromenia species from the Late Sinemurian to the Early Carixian) are older than the multicostate Terebratulids (Hesperithyris species from the Middle to Late Carixian).     

Microfacies and sequence stratigraphy of the Amapá Formation, Late Paleocene to Early Eocene, Foz do Amazonas Basin, Brazil

On the basis of thin-section studies of cuttings and a core from two wells in the Amapá Formation of the Foz do Amazonas Basin, five main microfacies have been recognized within three stratigraphic sequences deposited during the Late Paleocene to Early Eocene. The facies are: 1) Ranikothalia grainstone to packstone facies; 2) ooidal grainstone to packstone facies; 3) larger foraminiferal and red algal grainstone to packstone facies; 4) Amphistegina and Helicostegina packstone facies; and 5) green algal and small benthic foraminiferal grainstone to packstone facies, divisible locally into a green algal and the miliolid foraminiferal subfacies and a green algal and small rotaliine foraminiferal subfacies. The lowermost sequence (S1) was deposited in the Late Paleocene–Early Eocene (biozone LF1, equivalent to P3–P6?) and includes rudaceous grainstones and packstones with large specimens of Ranikothalia bermudezi representative of the mid- and inner ramp. The intermediate and uppermost sequences (S2 and S3) display well-developed lowstand deposits formed at the end of the Late Paleocene (upper biozone LF1) and beginning of the Early Eocene (biozone LF2) on the inner ramp (larger foraminiferal and red algal grainstone to packstone facies), in lagoons (green algal and small benthic foraminiferal facies) and as shoals (ooidal facies) or banks (Amphistegina and Helicostegina facies). Depth and oceanic influence were the main controls on the distribution of these microfacies. Stratal stacking patterns evident within these sequences may well have been related to sea level changes postulated for the Late Paleocene and Early Eocene. During this time, the Amapá Formation was dominated by cyclic sedimentation on a gently sloping ramp. Environmental and ecological stress brought about by sea level change at the end of the biozone LF1 led to the extinction of the larger foraminifera (Ranikothalia bermudezi).     

Tectonically driven carbonate ramp evolution at the southern Tethyan shelf: the Lower Eocene succession of the Galala Mountains,Egypt

The succession of the Galala Mountains at the southern Tethyan margin (Eastern Desert, Egypt) provides new data for the evolution of an isolated carbonate platform in the Early Eocene. Since the Late Cretaceous emergence of the Galala platform, its evolution has been controlled strongly by eustatic sea-level fluctuations and the tectonic activity along the Syrian Arc-Fold-Belt. Previous studies introduced five platform stages to describe platform evolution from the Maastrichtian (stage A) to the latest Paleocene shift from a platform to ramp morphology (stage E). A first Early Eocene stage F was tentatively introduced but not described in detail. In this study, we continue the work at the Galala platform, focussing on Early Eocene platform evolution, microfacies analysis and the distribution of larger benthic foraminifera on a south-dipping inner ramp to basin transect. We redefine the tentative platform stage F and introduce two new platform stages (stage G and H) by means of the distribution of 13 facies types and syn-depositional tectonism. In the earliest Eocene (stage F, NP 9b–NP 11), facies patterns indicate mainly aggradation of the ramp system. The first occurrence of isolated sandstone beds at the mid ramp reflects a post-Paleocene-Eocene thermal maximum (PETM) reactivation of a Cretaceous fault system, yielding to the tectonic uplift of Mesozoic and Palaeozoic siliciclastics. As a consequence, the Paleocene ramp with pure carbonate deposition shifted to a mixed carbonate-siliciclastic system during stage F. The subsequent platform stage G (NP 11–NP 14a) is characterised by a deepening trend at the mid ramp, resulting in the retrogradation of the platform. The increasing deposition of quartz-rich sandstones at the mid ramp reflects the enhanced erosion of Mesozoic and Palaeozoic deposits. In contrast to the deepening trend at the mid ramp, the deposition of cyclic tidalites reflects a coeval shallowing and the temporarily subaerial exposure of inner ramp environments. This oppositional trend is related to the continuing uplift along the Syrian Arc-Fold-Belt in stage G. Platform stage H (NP 14a–?) demonstrates the termination of Syrian Arc uplift and the recovery from a mixed siliciclastic carbonate platform to pure carbonate deposition.     

Matière organique sédimentaire et paléoenvironnements du Tithonien inférieur quercynois (France)

The Solen 98 well corresponds to the limestones of the Lower Tithonian Cazals Formation (Gigas Zone). The iterative succession of six sedimentary terms expresses a cyclic peritidal dynamic. Limited by two emersion surfaces, each sequence evolves from an upper subtidal lagoon to a tidal flat, upper intertidal or supratidal environment, and ends with open sea depositional bioclastic and oolitic shoals deposits. Hierarchical ascendant classification applied to palynological data define 6 palynofacies types associated with different depositional facies. Type 1, characterizing open marine deposits, shows a diversified and balanced assemblage. The blade-shape woody particles are abundant and the amorphous organic matter is absent. Types 2 and 3 are linked to lagoonal and skeletal shoals deposits. Then microfossil population is dominated by Corculodinium or long-spine Micrhystridium. The Shannon-Weaver and the equitability indices are moderate. Type 4 is associated with the upper tidal flat, lagoonal and skeletal shoal deposits. When microfossils are present, the algal assemblages are more balanced than in type 5. This type, observed in all the palaeo-environments except the open marine, is enriched in elements attributed to the Hyalinsphaeridia complex. The marine component assemblages are balanced. The amorphous organic matter is relatively abundant and the oxydized woody particles absent. Type 6, mainly composed of amorphous organic matter and phytoclasts, is principally associated with the stromatolitic facies of tidal flat deposits. The example of the Solen 98 well, shows that hierarchical ascendant classification method is well suited for identification of palynofacies     

La limite Kimméridgien-Tithonien et l'âge des formations du Jurassique supérieur de la Dorsale tunisienne, comparaisons avec l'Algérie et la Sicile

The discovery of the Lowermost Tithonian Hybonotum-Lithographicum Zone allows for the first time to define the Kimmeridgian-Tithonian boundary in the pelagic and transitional facies (Béni Kleb Fm) of the Tunisian Dorsale and to divide within the formation the Kimmeridgian-lower Tithonian grey and/or pseudonodular mudstone and the massive Tithonian limestones. The Hybonotum-Lithographicum Zone was not identified in the reefal facies (Ressas Fm) and the Kimmeridgian and Tithonian are not divided. The Ressas Fm starts earlier, with the Upper Oxfordian, Bimammatum Zone. The Kimmeridgian-Tithonian of the Tunisian Dorsale is compared with the corresponding beds in Algeria and Sicily.     

Les foraminifères du Paléocène et de l'Éocène basal du sillon nord-pyrénéen (Aquitaine, France)

This paper presents for the first time the inventory of the Paleocene and Lower Eocene foraminifers located in the North Pyrenean trough, between the Atlantic Ocean and the neighbourhood of the town Pau. They have been studied from three outcrops. The Bidart Beach section shows the Lasseube Formation from the Cretaceous/Paleogene boundary to the base of the P 3a zone. The Loubieng Quarry section, near Orthez, represents the upper P 3a zone and the lower P 3b zone as well as the Lasseube Formation / Pont Labau Formation boundary. The interval between the upper part of the P 3b zone and the upperest part of the P 5 zone crops out along the Gan - Rébénacq road with a hiatus located at the Paleocene / Eocene boundary, the whole interval belonging to the Pont Labau Formation. 394 taxons of foraminifers are present in this formations: 349 benthic and 45 planktonic species. The Velasco type benthic foraminifers show a middle bathyal depositional environment, with a paleobathymetry included between 500-600 m and 1000 m: Nuttallides truempyi, Osangularia velascoensis, Bulimina trinitatensis. The Midway type species which were transported by the turbidite currents from the lower to middle neritic environments are frequent as well as the Cretaceous reworked species. The species number is low: 29 in the iridium layer of the Cretaceous/Paleogene boundary (P 0 zone). Fauna grows rich quickly in the Pα zone reaching 129 species. The diversity grows up progressively from P α to the P 4a zone (NP 8). The disappearances are rare until his horizon, but their number is bigger than the number of appearances from the P 4b zone. It reaches their maximum between the P 4c zone and the P 5 zone. It shows that the decline of the Paleocene fauna begins around 2 million years before the thermal event of the Paleocene / Eocene boundary in the Aquitaine sections. The disappearances stay important in the Lower Eocene - Ypresian, but the appearance of lots of Eocene species show that the fauna renewal is located in this stage. The Cretaceous taxa dominate in the Paleocene benthonic fauna. The appearance or the disappearance of some species has a stratigraphic value in the Aquitaine region: the disappearance of Coryphostoma incrassata in the P 1b zone, the appearances of Plectina dalmatina, Elongobula grata (P α); Bulimina tuxpamensis (P 2); Tritaxilina cubensis, Thalmannita madrugaensis (P 3a); Svenia bulbosa (P 3b); Discorbis perovalis (P 4a/NP 7); Elongobula pulchra, E. pupa, Asterigerina bartoniana, Neorotalia gr. tuberculata (P 4a/NP 8); Bigenerina pannonica, Pentellina pseudosaxorum (P 5/NP 9-10).     

Upper Cretaceous paleogeography of the Central Southern Pyrenean Basins (Catalonia, Spain) from microfacies analysis and charophyte biostratigraphy

The most extensive latest Cretaceous deposits of the Pyrenees are non-marine facies traditionally called “Garumnian”, which represent the first continentalization of the Pyrenean Foreland Basins. The age and paleogeography of the basal Garumnian facies in the different parts of the Pyrenean Basin has been a matter of debate. Charophyte biostratigraphy and microfacies analysis suggest that the continentalization was diachronous in the Central Southern Pyrenean basins, i.e., between the Àger and Tremp basins, and the emersion progressed from south to north. In the Àger Basin, to the south, the first Upper Cretaceous non-marine rocks are represented by the La Maçana Formation. This unit is mainly formed by freshwater lacustrine limestones organized into hundreds of shallowing-upwards sequences ranging from deeper lacustrine facies, through marginal, well-illuminated environments dominated by characean meadows, and finishing with lakeshores dominated by clavatoracean meadows. The charophyte assemblage from the La Maçana Fm is mainly formed by Peckichara cancellata, P. sertulata, Microchara cristata, M. parazensis, Platychara caudata, and Clavator brachycerus, which belong to the Peckichara cancellata charophyte biozone (Late Campanian). In contrast, in the Tremp Basin, located to the north, the beginning of the non-marine sedimentation is organized into a few cycles of the well-known La Posa Fm. These cycles begin with brackish deposits formed by thick marls with euryhaline molluscs at the base, followed by lignite and brackish to freshwater limestones. The brackish facies are dominated by porocharaceans. The charophyte assemblage of the La Posa Formation is formed by Feistiella malladae, Peckichara sertulata, Microchara cristata, and Clavator brachycerus, which belong to the Septorella ultima charophyte biozone (Early Maastrichtian).     

Les Rhynchonelles du Bathonien du domaineprovencal: Liaison entre l'installation des peuplements et les modalités de la transgression bathonienne dans les Alpes-Maritimes

In the Maritime Alps, the Middle and Upper Bathoniancorresponds to a transgressive episode on the Provençal platform. The advancement of the marine invasion is very noticeable between Grasse and Antibes. The sediment shows the existence of a shallow marine environment in which benthic organisms were predominant.The deposits are at first varied: marly layers withbivalves (burrowers for the most part) and calcareous layers with monospecific populations of brachiopods (Burmirhynchia mediterranea nov. sp. in a calm environment, and B. turgidaBuckman in a more turbulent environment).The deposits then become uniform and show theexistence of very shallows environments: B. decorata kiliani nov. subsp. is the only representative of macrofauna in the micritic limestones that can be attributed to the Upper Bathonian.The Rhynchonellids, as on the other Bathonian carbonateplatforms of Western Europe, seem to be the only organisms likely to stay alive and proliferate in the specific environments in which entirely carbonate sediments are deposited in shallow water. Due to their relationships to those existing in other platforms, the species described in this article permit the clarification of biostratigraphic correlations.     

J. Deprat,l’Eubée (Grèce) et les fossiles introuvables

In Evia (Greece), limestones attributed to the lower Cretaceous by J. Deprat are in fact of Triassic to Upper Jurassic age. These erroneous attributions are based on the allegedly presence of Barremian and Albian fossils and on the supposed progressive passage of these limestones to the Cenomanian ones. Generally, except for the upper Cretaceous rich in Rudists and known since older works, a big part of the stratigraphical attributions of J. Deprat in Median Evia are erroneous.     

Stratigraphy and microfossils (radiolarians and planktonic foraminifers) of the Upper Cretaceous (upper Santonian–lower Campanian) Struganik limestone (Western Serbia)

Radiolarians and planktonic foraminifers were studied from several sections of the Upper Cretaceous lithographic limestones near Struganik Village (Western Serbia). These deposits were formed in a local basin, in a low-energy sedimentary environment surrounded by a shallow-water carbonate platform. The Struganik limestone is represented by alternating micritic limestone with calcarenite, rudite and tuffaceous rocks. The sections of the Struganik limestone have a narrow stratigraphic interval that covers the upper Santonian and probably includes the lower Campanian, with a total thickness reaching 120–150 m. The radiolarian zones Crucella robusta and Afens perapediensis were traced within the unit. The foraminiferal zone Dicarinella asymetrica was tentatively identified.     

Transitional reef-to-basin facies of Lower Frasnian limestones determined by microfacies analysis (Wietrznia,Holy Cross Mts,Poland)

Wietrznia section is situated between the shallow-water carbonate platform in the Kielce region and the Łysogóry basin. The transitional facies of the Wietrznia Frasnian includes two overlapping types of deposits: (1) thin-bedded dark-coloured limestone-marl alternations similar to the basin facies and (2) coarse-grained detrital limestones. Three lithotypes of limestones were identified: laminated or graded micritic, nodular, and detrital. The petrographic study makes it possible for the recognition of six major microfacies (MF 1 to MF 6). These lithotypes were formed by redeposition in a low- to high-energy environment. Their source material was the stromatoporoid-coral Dyminy reef in the central part of the Kielce region. Storms are considered to be the main agent, which causes in erosion and transport; micritic limestones and distal tempestites occur together, whereas detrital limestones are associated with proximal tempestites. Most probably, part of the detrital beds was formed as a result of grain-flow initiated under storm conditions.     

Environmental change in the Early Permian of NE Svalbard: from a warm-water carbonate platform (Gipshuken Formation) to a temperate,mixed siliciclastic-carbonate ramp (Kapp Starostin Formation)

A detailed facies study of Early Permian strata within NE Svalbard reveals a fundamental change of the depositional setting, from a restricted-marine, warm-water carbonate platform to an open-marine, temperate-water, mixed siliciclastic-carbonate ramp. The uppermost strata of the Gipshuken Formation (Templet and Sørfonna members; Sakmarian–early Artinskian?) consist of microbialites (algal mats), mudstones, bioclastic/peloidal limestones, carbonate breccias and Microcodium facies reflecting peritidal platform areas and supratidal sabkhas. A mixed heterozoan/reduced photozoan assemblage indicates temperate-water conditions within neighboring deeper, open-marine mid-platform areas, while warm-water conditions still prevailed within inner platform zones. In contrast, the lowermost strata of the overlying Kapp Starostin Formation (Vøringen Member; late Artinskian?–Kungurian) show a fully heterozoan biotic assemblage reflecting temperate water conditions within open-marine, storm-dominated, nearshore to transitional offshore areas of a mixed carbonate-siliciclastic ramp. The Vøringen Member comprises three facies associations, which form a shallowing-upward sequence subsequent to an initial transgression. The sediments reflect bryozoan bioherms in most distal areas, followed by stacked tempestites of sandy brachiopodal shell banks and Skolithos piperocks, grading into broad sand flats in most proximal areas of the inner ramp. The above environmental change is regarded as a regional event taken place across the entire shelf along the northern margin of Pangea and is attributed to paleoclimatic, paleoceanographic, as well as paleogeographic changes, possibly related to the overall northwards drift of the supercontinent. An abrupt increase in terrigenous input coinciding with this change is ascribed to the uplift of a new local source area, probably to the north or east of the investigation area.     

Controls on Devonian hemi-pelagic limestone deposition analyzed on cephalopod ridge to slope sections,Eastern Anti-Atlas,Morocco

The hemi-pelagic Tafilalt Ridge separating the Maider Basin from the Tafilalt Basin developed progressively from an Early Devonian homoclinal ramp, through a Middle Devonian ramp-slope stage of moderate topography, to a mature cephalopod ridge during the Late Devonian and formed a spur-like element extending from the southern shallow-water Maider Platform to the broader northern hemi-pelagic Tafilalt Platform. During the Middle Devonian, thick lowstand aprons were shed onto the ridge-slope from an active mid-ramp carbonate factory in the south (Maider Platform). The shallow-water derived sediments first by-passed the central paleohigh, but then onlapped the ridge during start of sea-level rise. The allodapic limestones (storm-induced turbidites, tempestites, and debrites) of the aprons consist of large parts or entirely of reworked lithic peloids. The lithic peloids are interpreted as the main foundation of all micritic lithofacies types in the distal ramp locations, including those on the hemi-pelagic cephalopod ridge. Lateral facies transition of allodapic limestones into nodular cephalopod limestones on the ridge suggests the latter originate from allodapic beds and were subsequently transformed into nodular limestones by bioturbation, early diagenesis, and the faunal input from a hemi-pelagic community. Iron-rich hardgrounds formed on the ridge during major regressive phases as a result of increased winnowing by the wave-base and correlate with siliciclastic turbidite deposition on the slope. The hardgrounds can be correlated with hiatuses on the Tafilalt Platform, which formed a broader hemi-pelagic swell to the north. During the Late Devonian, the southern Maider Basin carbonate factory became unproductive or disappeared, and a ridge facies of truly hemi-pelagic autochthonous limestones developed. Allodapic deposits on the slope were shed from the ridge itself at this time but did not form well-defined aprons.     

Les cétacés des gravures rupestres néolithiques de Bangu-dae (Corée du Sud) et les débuts de la chasse à la baleine dans le Pacifique nord-ouest

The Neolithic site of Bangu-dae (6000-1000 B.C.), south-east of the Korean peninsula, presents numerous rock carvings of cetaceans (n = 46, 19.9% of the figures), and especially large species. Among these two families of baleen whales (Balaenidae and Balaenopteridae) and the sperm whale can be identified. This site also presents whaling scenes suggesting that the Neolithic populations who lived along the coast of Korea were among the first to take advantage of coastal whales. All these carvings give exceptional evidence on the prehistoric beginning of whaling.     

Early cretaceous serpulid limestones: Chachao formation,Neuquen basin,Argentina

Summary Colonial serpulids (Sarcinella) are common within some limestones of the lower Chachao Formation (Valanginian) near Malargüe city at the northern border of the Neuquem basin, Argentina. The shallowing-upwards sequence is characterized by low-energetic micritic carbonates. The serpulid limestones mark the transition from a carbonate ramp stage to a platform stage.     

Stratigraphy, geometry, and facies of a Middle Devonian ramp-to-basin transect (Eastern Anti-Atlas, SE Morocco)

Summary In the castern Anti-Atlas (SE Morocco), a small sedimentary basin (Mader Basin) evolved during the late Palacozoic. The Middle Devonian deposits consist of shales and limestones with a thickness up to 700 m in the depocentre. Sedimentary structures and sole marks of Middle Devonian limestones indicate transport from the northwest and the south towards the basin centre, located in the central Mader area. Lithostratigraphic, biostratigraphic, and dynamic stratigraphic approaches were applied to correlate stratigraphic sections. Five correlatable large-scale base-level hemicycles were recognized in the Middle Devonian succession. Thickness trends of Middle Devonian deposits, regional correlations, and facies-trends reveal the geometry of a carbonate ramp. The carbonate ramp was slightly inclined (<1°) to the NE. A sedimentary wedge, consisting of limestones and limestone/marl alternations, was deposited during the Eifelian and marks the transition from the ramp to the adjacent basin. Middle Devonian water depths are estimated as close to and within the storm wave-base at the southern area of the ramp and far below storm wave-base in the northeastern part of the ramp. Shallowest conditions (inner-ramp environment), close or within the fairweather wave-base, existed during the early Givetian as documented by the abundance of recfal fauna (stromatoporoids, corals) and calcimicrobes (lumps, micritic envelopes) in the eastern and southeastern area of the ramp.     

Stratigraphie, paléoécologie et foraminifères du paléogène des Alpes Maritimes et des Alpes de Haute-Provence (Sud-Est de la France)

Paleogene sedimentation in the Alpes Maritimes and Alpes de Haute Provence regions is composed of one complete sedimentary sequence. This sequence begins with the continental Formation from Microcodium and continues with the Cerithium layers, the Calcaires Nummulitiques and the Marnes Bleues, which are overlaid by the turbidites of the Grès d’Annot Formation. Sedimentation starts in the Nummulites perforatus zone close to the base of ‘the Truncorotaloides rohri zone (P 14) and ends in the Cassigerinella chipolensis-Pseudohastigerina micra zone (P 18) and the NP21 zone in the upper part of the Grès d’Annot. More biomarkers were used in order to define a more detailed local biozonation (biozones AMP 1 to AMP 7). Four local zones were also defined by the last occurrence of Nummulites millecaput and N. perforatus-N. ptukhiani and then by the first appearance of N. retiatus (AMGF 1-4). The evolution of benthic foraminiferal assemblages shows an increase in bathymetry from the internal platform in the Cerithium layers to the calcareous platform with large foraminifers, then to the external platform and the deep offshore environment of the Marnes Bleues and Grès d’Annot. Low faunal diversity in the Grès d’Annot together with the predominance of agglutinated species indicates a poorly oxygenated, organic rich and turbidite environment. Seven steps (SD 1 to SD 7) in the Eocene marine transgression are shown from East to West by detailed local biozonation and sequence analysis. Grès d’Annot sedimentation is also diachronous, beginning within the Truncorotaloides rohri zone (P 14, AMP 1) in the East and ending within the Pararotalia opima opima zone (P 20, middle Rupelian) in the West (Barrême). Small foraminifer Paleogene fauna from the Alpes Maritimes and Alpes de Haute Provence was studied from 400 samples. It is composed of 378 species. Two new taxa are proposed: Fissurina niceana n. sp. and Globocassidulina alpina n. sp. The species from the Escarène and Gorbio neighborhood described by M. von Hantken (1884) were re-examined.