Sequence stratigraphy of Eocene incised valley clastics and associated sediments,Island of Rab,northern Adriatic Sea,Croatia

Clastic sediments of Middle–Late Eocene age were studied on the Island of Rab (northern Adriatic Sea, Croatia) in order to reconstruct their depositional history, depositional environments, and geometry of sandstone bodies. Detailed outcrop logging and mapping revealed the response of depositional systems to frequent relative sea-level changes, which initiated significant basinward and landward shifts of facies, respectively. Tidal sandstones are commonly underlain by shoreface sandstones, and overlain by offshore sandy marls, whereas the latter are again overlain by shoreface sandstones. Major relative sea-level falls initiated basinward shift of depositional systems and the incision of incised valleys or estuaries, and consequently truncated the underlying shelf sediments. In some cases, the accelerated sea-level fall caused rapid shoreface progradation which is interpreted as a forced regression. Relative sea-level rise caused flooding of the incised relief, and deposition of tidal sandstone bodies which overlie type-I sequence boundaries. The coarse lag sediment of these sequence boundaries locally disappears laterally, and the boundary is granulometrically less prominent. All of the major bounding surfaces have been recognized in the sections studied, although the maximum flooding surface is recognized as a thin “zone” instead of a single surface. Altogether, 28 complete sequences, and 15 parasequences are recognized in the informal unit of the Lopar sandstones, documenting the depositional response to high-frequency relative sea-level oscillations. They have so far not been recognized in the Eocene of the eastern Adriatic region.     

Characterization and astronomically calibrated age of the first occurrence of Turborotalia frontosa in the Gorrondatxe section, a prospective Lutetian GSSP: implications for the Eocene time scale

The Gorrondatxe section, a prospective Lutetian Global Stratotype Section and Point (GSSP), has recently been used as the master reference section to reassess the correlation between Eocene magnetostratigraphic and calcareous planktonic biostratigraphic scales. However, the exact calibration of some events remained ill defined, as they were thought to be missing in Gorrondatxe due to a fault. The most important missing events were the first occurrence of the planktonic foraminifera Turborotalia frontosa and the C22n/C21r chron boundary. Either might be a reliable correlation criterion for the Ypresian/Lutetian boundary, as both approach the age of the original Lutetian Stratotype. New studies allowed the identification of the former event 9 m above the Gorrondatxe fault, within magnetic polarity Chron C21r and calcareous nannofossil Zone CP12a. Distinctive test features that characterize the most primitive morphotype of T. frontosa are described. Despite the high turbidite content, recurrent pelagic limestone–marl couplets and bundles occur, whose formation was driven by precession and eccentricity astronomical cycles. The first occurrence of T. frontosa was found 27 couplets and 5.5 bundles (60 m) below the first occurrence of the calcareous nannofossil Blackites inflatus , which is dated at 48 Ma. Hence, the age of the first occurrence of T. frontosa is estimated at 48.55 Ma, confirming that it is the most suitable planktonic foraminiferal correlation criterion for the Ypresian/Lutetian boundary. These results show that the stratigraphic interval missing due to the Gorrondatxe fault cannot be greater than a few metres and reinforce the value of this section as a prospective Lutetian GSSP.     

Integrated magnetobiochronology of the Early/Middle Eocene transition at Agost (Spain): Implications for defining the Ypresian/Lutetian boundary stratotype

In this paper, we present an integrated study of a 115‐m‐thick section that spans the Ypresian/Lutetian boundary at Agost (Betic Cordillera, SE Spain). Our study includes magnetostratigraphic results and biostratigraphic and palaeoenvironmental data derived from planktic foraminifera, small and larger benthic foraminifera, and calcareous nannofossils. Our results demonstrate that the Agost section is continuous and spans from Zones P9 to P12 (E7 to E10), Zones CP11 to CP14a (NP13 to NP16), Zones SBZ11 to SBZ15, and Chrons C22n to C19r. The first occurrence (FO) of H. nuttalli (base of P10) and the FO of G. nuttalli (base of E8) are found within Chron C20r, at a much younger age (3–5 Myr) than previously considered in standard calibration schemes. Similarly, the boundary between SBZ12 and SBZ13 is located within Chron C21n, also at a younger age than previously considered. On the contrary, the FO of B. inflatus (base of CP12b) is found within Chron C21r, which conforms to the magnetostratigraphically calibrated age of ca. 48 Ma (middle part of C21r) considered in standard calibration schemes. These results corroborate earlier studies and indicate that all the events that have been proposed to mark the Ypresian/Lutetian boundary appear at different stratigraphic intervals and have different ages. Based on our results from Agost and on data from other sections elsewhere, we suggest that the Ypresian/Lutetian boundary might be approximated by the FO of B. inflatus (base of CP12b). The Agost section might be considered as a potential candidate to locate the Global Stratotype Section and Point (GSSP) of the base of the Lutetian Stage, because it includes all the events that might be selected as marker events for the Ypresian/Lutetian boundary and it fulfils most of the geological, biostratigraphic and infrastructure requirements demanded for definition of a GSSP.     

Lutetian calcareous nannofossil events in the Agost section (Spain): implications toward a revision of the Middle Eocene biomagnetostratigraphy

This paper presents a detailed calcareous nannofossil biostratigraphy of the entire Lutetian of the Agost section (Betic Cordillera, SE Spain). This investigation integrates and improves on previous study performed through the Ypresian/Lutetian boundary by the authors on this succession. The new revision of the integrated bio‐magnetobiochronology of the Early/Middle Eocene interval revealed highly diversified calcareous nannofossil assemblages, characterizing more than 8 Myr of climatic variability. The studied interval spans from Zone CP11 to Subzone CP14a and from the upper part of Zone NP13 to the base of Zone NP16 of calcareous nannofossil standard zonations. The revision of the calcareous nannofossil content enabled the identification of numerous secondary events which greatly improved the stratigraphic resolution of this time interval. An important re‐organization of the nannoflora was observed during the Y/L transition, when Reticulofenestra and Dictyococcites (Noelaerhabdaceae) became the most important genera in terms of abundance and dispersal, dominating the Middle Eocene nannofossil assemblages and replacing Toweius and Discoaster taxa characteristic of the lower Eocene. Pentaliths and Blackites experience a great expansion and diversification, whereas Discoaster and Chiasmolithus which are well diversified but never abundant during the Lutetian show a slow turnover. A reassessment of the major bio‐events observed in the Noelaerhabdaceae family as well as revision and correlation of these events with the classical Italian sections (Contessa and Bottaccione) are presented. The new results show that biostratigraphic problems related to the Middle Eocene chronology are not limited to the correlation between calcareous nannofossils and planktonic foraminiferans at the Y/L transition but extend to calcareous nannofossil events commonly used for correlating the Bartonian.     

Lithostratigraphie et biostratigraphie des formations paléocènes et éocènes entre Bayonne et Pau (SW France)

The lithostratigraphy and biostratigraphy of the Paleocene and Eocene formations have been reconsidered on the basis of 18 dated boreholes that intersect the Basque Country, Peyrehorade, Sainte-Suzanne and Sauvelade allochthonous tectonic units, as well as the autochthonous units of the Pey-Saint-Lon anticline, the Arzacq Basin and the North Pyrenean Trough. Correlation of the formations identified in the boreholes and at outcrop has made it possible to outline the sedimentary evolution of this region during the Early Paleogene and to date the various stages of Pyrenean compression on the basis of sedimentary gaps and syntectonic detrital input. The Lasseube Formation is present over the entire study area. Sedimentation becomes differentiated during the Late Selandian-Early Ypresian period. In the North Pyrenean Trough and in the Peyrehorade, Sainte-Suzanne and Sauvelade units, the detrital-clayey Pont-Labau Formation is well developed and all its members are represented (Guillempau, Latapy, Néez, Libaros and Artigueloutan; zones upper P 3b-P 6b; upper NP 5-NP 11). A sedimentary gap showing erosion, and involving zones upper P 3b-upper P 4a and upper NP 5-NP 7, characterises the Basque units, the Pey-Saint-Lon anticline and the western part of the Arzacq Basin. Sedimentation recommences in zone P 8 with middle-bathyal deposits of the Cassoua Member and then continues with the Artigueloutan Member (transition facies towards the Louts Formation) or limestone resembling that of the Meilhan Formation. The Gan Formation shows an east-west polarity. In the east, between the Sainte-Suzanne Unit and the North Pyrenean Trough, the formation is argillaceous with a dominant neritic character, apart from a circalittoral to epibathyal passage in its lower part (zone P 7) containing numerous planktonic foraminifera. The formation is of a detrital and carbonate nature in the west (Sainte-Marie-de-Gosse 1). The bathyal Donzacq Formation appears to transgress a previously deformed surface. Two domains existed during the Lutetian: a continental to neritic domain in the south and a bathyal domain in the north (the Saint-Geours-d'Auribat and Miretrain formations) separated by a variably thick transition zone that is affected by thrust fronts. Two new formations - the Orthez and Sorde-l'Abbaye formations - are proposed, and the Marly limestone formation of Saint-Barthélémy (Douvillé, 1905) is redefined. The Orthez Formation (Sauvelade Unit) is composed of marl and continental conglomerate with neritic carbonate interbedding and belongs to the sub-zones NP 15a and b. The Sorde-l'Abbaye Formation (Peyrehorade Unit and the Basque units p. p.) is composed of neritic carbonate sediments (Lutetian-Priabonian). The Saint-Barthélémy Formation is made up of syntectonic conglomerate, turbiditic limestone and pelagic marl in the central part of the Basque units (NP 15a-NP 16). The Bartonian and Priabonian stages are characterised by carbonate sediments in the Arzacq Basin (Siest Formation). Its base is diachronous: Upper Lutetian (zone SB 16) in the east and Late Bartonian grading to Priabonian in the west (zones SB 17/18 and SB 19). The sediments are argillaceous (Côte des Basques Formation) along the Atlantic coast, in the central part of the Basque units and in the Bayonne-Cauneille syncline. Major thickness variations reflect tectonic phases at the top of the Lasseube Formation in the north (erosion pre NP 8), the Néez Member (NP 7/NP 8 boundary), the Artigueloutan Member (NP 11/NP 12 boundary), and the Gan Formation (P 8/P 9 boundary). The syntectonic conglomerate and breccia indicate the development of thrust fronts in the Libaros Member (NP 8), at the base of the Pillardou and Artigueloutan members (NP 9b, c-NP 10), in the Saint-Geours-d'Auribat Formation (NP 14b) and in the Orthez and Saint-Barthélémy formations (between zones NP 15a and NP 16).     

The Upper Eocene South Pyrenean Coastal deposits (Liedena sandstone, navarre): Sedimentary facies, benthic formanifera and avian ichnology

Summary During the 1960's and the 1970's the Liedena Sandstone was a type deposit for “flysch-like facies” (sandstone and lutite alternations) of coastal sedimentary systems. However, the depositional system of these beds was never accurately defined. The sedimentological analysis along 100 km of outcrops in the western part of the South Pyrenean Zone (Navarre) allows these peculiar facies to be assigned to a mixed intertidal flat. Furthermore, sandy beach facies, different types of heterolithic, backbarrier deposits and conglomeratic, fluviatile facies have been recognized associated with these intriguing deposits. Generally, a northwestward-facing barrier-island system or wave-dominated delta was the likely depositional environment. The benthic foraminiferal assemblage in the intertidal deposits exhibits the typical characteristics of a marginal marine environment: extremely high dominance of one species (Pararotalia inermis), low species diversity, and a hyaline dominance with discrete amounts of miliolids. Furthermore, the most abundant species indicates that the Liedena Sandstone was deposited during the Late Eocene. Abundant footprints of aquatic birds are known in the tidal flat deposits. Six morphotypes have been distinguished: two (types 1 and 2) are ciconiforme-like; type 1 is here assigned to a new ichnotaxon,Leptoptilostipus pyrenaicus and is one of the oldest occurrences of Ciconiiforme-like ischmites in the fossil record. Two other morphotypes (5 and 6) are similar to those of the Charadriiformes and are refeered to asCharadriipeda. Finally, the affinities of the two remainder morphotypes (3 and 4) are unclear, they could have been made by Charadriiformes. Synsedimentary tectonic activity controlled the evolution of the depositional system, as the area of deposition of the Liedena Sandstone was progressively incorporated into the active thrust sheets of the Pyrenean Orogen during the Late Eocene. The structural uplift and the large amount of sediments derived from the adjacent highlands induced progradation of the depositional system and the definitive retreat of the sea from the South Pyrenean Zone.     

Three new dinoflagellate cysts from the Moroccan Paleocene-Eocene phosphates

Moroccan phosphate deposits from the Phosphate Plateau (Oulad Abdoun basin, near Khouribga) contain varied and well preserved dinoflagellate cysts. Among them, a new genus: Bitubericysta and three new species: B. boroujiana, Liesbergia abdounensis and Spinidinium stellatum are described in this paper. The two gonyaulacoid cysts have been found in Upper Paleocene (Thanetian) and Lower Eocene (Ypresian) sediments, the peridinioid cyst has been observed in Upper Paleocene (Thanetian) and basal Eocene (basal Ypresian) material.     

Facies distribution and sequence stratigraphy of the Coniacian–Santonian succession of the Bangestan Palaeo-high in the Bangestan Anticline,SW Iran

This study is focused on the sedimentary environments, facies distribution, and sequence stratigraphy of the Coniacian–Santonian sediments of the Bangestan Palaeo-high in the Bangestan Anticline (Zagros, Iran). These sediments are subdivided into nine microfacies types belonging to various sedimentary environments, ranging from continental lacustrine to very shallow and relatively deep-water (hemipelagic to pelagic) marine environments. The lower boundary of the studied sections is characterised by an unconformity. The lacustrine and very shallow marine sediments at the base of the studied sections are interpreted as a lowstand system tract. The establishment of an open shelf carbonate platform took place during the transgressive system tract. The maximum flooding zone of the Early Santonian is an important surface because it extends from the distal to the proximal part of the depositional environment.     

Sea-level dynamics and palaeoecological factors affecting trace fossil distribution in Eocene turbiditic deposits (Gorrondatxe section,N Spain)

Ichnological analysis of the upper Ypresian–lower Lutetian interval at the Gorrondatxe section (W Pyrenees, N Spain), reveals a relationship between sea-level dynamics and the eco-sedimentary factors influencing trace fossil assemblages. The 600 m thick section of deep-sea turbiditic deposits contains 41 ichnospecies belonging to 28 ichnogenera, which are typical of the Nereites ichnofacies, and mostly of the Paleodictyon ichnosubfacies, suggesting deposition in a basin plain to fan-fringe setting. The trace fossil diversity and abundance fluctuate, irrespective of turbidite frequency. These ichnological features are strongly affected by trophic level changes related partly to sea-level dynamics according to the sequence stratigraphic interpretations for the studied section. Temperature, oxygenation and substrate changes are also considered as relevant factors. Increased ichnodiversity, particularly among graphoglyptids, coincides with moderate oligotrophy and stable ecological conditions. Eutrophisation, lowered oxygenation and drop of temperature, typical of low sea level, can reduce ichnodiversity.     

New eocene oysters and the final regression at the southern Rim of the central High Atlas (Morocco)

The oysters Ostrea (Ostrea) todraensis n. sp. and Ostrea (Ostrea) sidialiensis n. sp. are described from the uppermost marine beds south of the central High Atlas in two sections west of Tinerhir. The oysters and the codiacean alga Ovulites margaritula (Lamarck, 1801) Lamarck, 1816 indicate a final regression at the end of Middle Eocene times, i.e. earliest at the end of the Lutetian and latest at the end of the Bartonian. The oysters lived in muddy lagoonal environments sealed off from the sea by oolitic-bioclastic carbonate sand shoals and bordered in landward direction by sebkha-like redbed deposits. Taxonomy and systematic affinities of the oysters are discussed. Their shell structures and depositional history are described in respect to sedimentary infillings. Some selected aspects of biometry explain differences in shell morphometry both between different valves of the same species and equivalent valves from the different populations, illustrating the importance of size and location of the adductor muscle scar.     

New larger foraminifers from the Eocene of the Crimea (Ukraine) and Mangyshlak (Western Kazakhstan)

Two new species of Nummulites and one subspecies of Orbitoclypeus from the Eocene of the Crimean Mountains and Mangyshlak Peninsula are described in detail. Nummulites alexisi sp. nov. and Orbitoclypeus munieri major subsp. nov. come from the Upper Ypresian, while Nummulites ninikae sp. nov. is from the Lower-Middle Lutetian. The phylogenetic position of new taxa is discussed.     

A new basal tomistomine (Crocodylia,Crocodyloidea) from Issel (Middle Eocene; France): palaeobiogeography of basal tomistomines and palaeogeographic consequences

A skull and mandible of a crocodylian from the late Lutetian of Issel, previously described as ‘Atacisaurus glareae’ is reconsidered. The holotype of ‘A. glareae’, a partial mandible, is lost, and the skull cannot be designated as a lectotype for the species. ‘Atacisaurus glareae’ is thus a nomen dubium. The skull bears a combination of characters, allowing us to assign it to the genus Kentisuchus. It differs from the, until now, only known species Kentisuchus spenceri from the Ypresian of England, in having a more robust snout, with the constriction of the snout at the level of the seventh–eighth teeth being 80% of the largest maxillary width, and not bearing anteroposterior shallow fossae along the lacrimomaxillary sutures. A new species is thus erected, K entisuchus astrei sp. nov. Phylogenetic analysis confirms that the genus Kentisuchus is one of the most primitive tomistomine. The phylogenetic and palaeogeographic distribution suggests that Kentisuchus was isolated in the Atlantic Ocean, and Ebro (Spain) and Aquitaine (France) basins, during the Ypresian, and that the south Pyrenean marine corridor between the Atlantic Ocean and the Tethys could have closed during the early Ypresian, earlier than previously supposed. This could be correlated with the first mammal migrations from the Iberian Peninsula to Southern France. The palaeogeographic distribution of early and middle Eocene tomistomines also suggests the possible presence of a marine corridor between the North Sea and the Central Tethys through the Polish Lowlands Basin during the early Lutetian. This marine corridor could be informative for studies on mammal migration, as the presence of a north–south marine corridor necessarily means there is an absence or less efficient east–west terrestrial passage. This could have consequences on the history of Asian–European mammal migrations.     

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).     

Integrated analyses of litho- and biofacies in a Pliocene cyclothemic, alluvial to shallow marine succession (Tuscany, Italy)

Lithofacies analysis of the upper part of the Pliocene succession of the Valdelsa basin (central Italy) unravelled a number of depositional environments, ranging from alluvial plain to coastal, to marine. Strata are arranged in a hierarchy of elementary and composite unconformity-bounded units. A palaeoecological study of macro- (molluscs) and microfossils (pollen, dinocysts, foraminifera) allowed to finely reconstruct sub-environments within fine-grained terrestrial, coastal and marine deposits and thence to track the spatial and temporal change of physical conditions. The stacking pattern of sedimentary units highlights the lateral switching of onshore-offshore gradients and documents relative sea-level changes. These units are interpreted in a sequence stratigraphic framework. Elementary depositional sequences are arranged to form six composite depositional sequences, in turn encased within two major synthems. This hierarchy of unconformity-bounded sedimentary units suggests that sea-level variation has occurred at different time-frequencies. Glacio-eustasy and active tectonism are discussed as the main forcing factors regulating the different scales of sedimentary cyclicity.     

Distribution patterns of benthic foraminifera across the Ypresian–Lutetian Gorrondatxe section,Northern Spain: Response to sedimentary disturbance

We present a study of benthic foraminiferal assemblages from an Ypresian–Lutetian distal submarine fan system in the lower bathyal Gorrondatxe section (Basque-Cantabrian Basin, northern Spain). The objective of our study is to analyze the benthic foraminiferal distribution patterns and their response to sedimentary disturbance and related factors.Assemblages contain a high percentage of allochthonous taxa, such as asterigerinids and other shallow water taxa, which were transported downslope by turbidity currents.Detailed quantitative analyses, supported by R-mode cluster and Detrended Correspondence Analyses (after removing allochthonous taxa from the foraminiferal counts) allowed us to identify 6 assemblages that are divided into two groups related to the turbidite content in the Gorrondatxe section. Assemblages 1, characteristic of the turbidite-poor intervals with low sedimentary disturbance, include assemblage 1a (with highly diverse common middle–lower bathyal calcareous taxa) assemblage 1b (with common agglutinated taxa, mainly trochamminids), and assemblage 1c (characterized by calcareous taxa that are also common in the turbidite-rich interval).Assemblages 2, characterized by a high dominance, prevail in the turbidite-rich interval, and include assemblage 2a (characterized by the dominance of infaunal bolivinids and epifaunal cibicids), assemblage 2b (typified by moderate to low diversity and dominated by deep-infaunal Globobulimina species), and assemblage 2c (typified by very abundant suspension-feeding astrorhizids). The high abundance of bolivinids and Globobulimina species may be related to an enhanced input of low-quality organic matter transported by turbidity currents to the seafloor, representing different stages of recolonisation after disturbance and different energy regimes. High current activity was probably responsible for the abundance of cibicids, while moderate to low diverse and high dominance assemblages characterize the recolonisation of the substrate after disturbance.We conclude that sedimentary disturbance and other related factors such as current activity, resuspension of sediments at the seafloor, and supply of organic matter (and its quality) played an important role in the distribution of benthic foraminifera in the Gorrondatxe section. The identification of allochthonous taxa emerges as an essential aspect of the study of environments with sedimentary disturbance.     

Quantification of high-frequency sea-level fluctuations in shallow-water carbonates: an example from the Berriasian–Valanginian (French Jura)

When quantifying sedimentary processes on shallow carbonate platforms, it is important to know the high-frequency accommodation changes through time. Accommodation changes in cyclic successions are often analysed by simply converting cycle thickness to Fischer plots. This approach is not satisfactory, because it does not account for differential compaction, possible erosion, sea-level fall below the depositional surface, or subtidal cycles. An attempt is made here to reconstruct a realistic, high-frequency accommodation and sea-level curve based on a detailed facies and cyclostratigraphical analysis of Middle Berriasian to Lower Valanginian sections in the French Jura Mountains. The general depositional environment was a shallow-marine carbonate platform on a passive margin. Our approach includes the following steps: (1) facies interpretation; (2) cyclostratigraphical analysis and identification of Milankovitch parameters in a well-constrained chronostratigraphic framework; (3) differential decompaction according to facies; (4) estimation of depth ranges of erosion and vadose zone; (5) estimation of water-depth ranges at sequence boundaries and maximum flooding intervals; (6) estimation of mean subsidence rate; (7) classification of depositional sequences according to types of facies evolution: ‘catch-up’, ‘catch-down’, ‘give-up’, or ‘keep-up’; (8) classification of depositional sequences according to long-term sea-level evolution: ‘rising’, ‘stable’, ‘falling’; (9) calculation of ‘eustatic’ sea-level change for each depositional sequence using the parameters inferred from these scenarios, assuming that sea-level cycles were essentially symmetrical (which is probable in Early Cretaceous greenhouse conditions); (10) calculation of a sea-level curve for each studied section; (11) comparison of these curves among each other to filter out differential subsidence; (12) construction of a ‘composite eustatic’ sea-level curve for the entire studied platform; (13) spectral analysis of the calculated sea-level curves. Limitations of the method are those common to every stratigraphic analysis. However, the method has the potential to improve the original cyclostratigraphical interpretations and to better constrain the high-frequency sea-level changes that control carbonate production and sediment fluxes.     

First record of non-marine ostracods from the Paleogene “hamadian deposits” of Méridja area,west of Bechar (southwestern Algeria)

A new non-marine ostracod fauna from the Paleogene “hamadian deposits” outcropping west of Bechar (southwestern Algeria) has been recovered from lacustrine to fluvial deposits of the Oued Méridja section and fluvial deposits on the southern edge of the Hamada de Méridja section. Recently, these sections have been dated as late Thanetian – early Ypresian (latest Paleocene to earliest Eocene) and Ypresian – earliest Lutetian (early to earliest middle Eocene), respectively, based on charophytes. The associated ostracod fauna recovered consists of relatively mostly moderately to badly preserved specimens and comprises 14 taxa, none of which could be identified to species level in view of its poor state of preservation; we have nevertheless been able to identify and describe the following taxa: Herpetocypris sp., Cyprinotus? sp., Heterocypris? sp. 1 and sp. 2, Cypris? sp., Ilyocypris sp., Cytheroidea indet. sp. 1 and sp. 2, Limnocytheridae indet. sp. 1, Cypridoidea indet. sp. 1, Cyprididae indet. sp. 1, and Ostracoda indet. sp. 1, 2 and 3. Only Heterocypris sp. 1 occurs in both sections. Although the fauna can as yet not be related to the few other contemporaneous faunas reported from the wider palaeogeographic area, it adds important new information to our poor knowledge on Eocene non-marine ostracods in North Africa and southern Europe. The Méridja sections and area are promising regarding the discovery of more, better preserved material and further studies, and one main limitation to the correlation of the fauna is the hitherto insufficient taxonomic knowledge on many faunal elements of Eocene non-marine ostracods to which our section contributes considerably.     

Agglutinated conical foraminifera from the Lower-Middle Eocene of the Trentinara Formation (southern Italy)

Five taxa of agglutinated conical foraminifera were recorded for the first time in the Trentinara Formation, and two of them are new. Barattolites trentinarensis n. gen. n. sp. shows high conical shape, an eccentric proloculus, trochospiral early chambers, two orders of radial subepidermal partitions and columnar pillars. It is recorded in the Ypresian of Panno Bianco Mt. (Calabria) and in the Ypresian-Lower Lutetian of Serra Pastorella (Basilicata). Pseudochrysalidina (?) variospira n. sp. shows a high conical test, a trochospiral juvenile growth stage, a megalosphere in apical position, and low pillars and chambers in the adult stage. It is known in the Ypresian of Serra Pastorella. Agglutinated conical foraminifera fill the late Lower to early Middle Eocene gap in their Paleogene record. Their very intermittent record is due to their extremely narrow ecological range.     

The oldest mammals from Antarctica,early Eocene of the La Meseta Formation,Seymour Island

New fossil mammals found at the base of Acantilados II Allomember of the La Meseta Formation, from the early Eocene (Ypresian) of Seymour Island, represent the oldest evidence of this group in Antarctica. Two specimens are here described; the first belongs to a talonid portion of a lower right molar assigned to the sparnotheriodontid litoptern Notiolofos sp. cf. N. arquinotiensis. Sparnotheriodontid were medium‐ to large‐sized ungulates, with a wide distribution in the Eocene of South America and Antarctica. The second specimen is an intermediate phalanx referred to an indeterminate Eutheria, probably a South American native ungulate. These Antarctic findings in sediments of 55.3 Ma query the minimum age needed for terrestrial mammals to spread from South America to Antarctica, which should have occurred before the final break‐up of Gondwana. This event involves the disappearance of the land bridge formed by the Weddellian Isthmus, which connected West Antarctica and southern South America from the Late Cretaceous until sometime in the earliest Palaeogene.     

Correlation between the Paleocene/Eocene boundary and the Ilerdian at Campo, Spain

The Ilerdian is a well-established Tethyan marine stage, which corresponds to an important phase in the evolution of larger foraminifera not represented in the type-area of the classical Northwest-European stages. This biostratigraphic restudy of its parastratotype in the Campo Section (northeastern Spain) based on planktic foraminifera, calcareous nannofossils, dinoflagellate cysts and the distribution of the stable isotopes ∂¹³C and ∂¹⁸O is an attempt to correlate the Paleocene/Eocene boundary based on a characteristic carbon isotope excursion (CIE) marking the onset of the Initial Eocene Thermal Maximum (IETM) and the Ilerdian stage. The base of this ∂¹³C excursion has been chosen as the criterion for the recent proposal of the Global Stratotype Section and Point (GSSP) of the base of the Eocene (= base of the Ypresian) in the Dababiya Section (Egypt) to which an age of 54.9 Ma has been attributed. This level is also characterized by a marked extinction among the deep-water benthic foraminifera (Benthic Foraminifera Extinction Event, BFEE), a flood of representatives of the planktic foraminiferal genus Acarinina and the acme of dinoflagellate cysts of the genus Apectodinium. In the Campo Section, detailed biozonations (planktic foraminifera, calcareous nannofossils, dinoflagellate cysts) are recognized in the Lower and Middle Ilerdian. The correlation with the Ypresian stratotype is based on dinoflagellate cysts and calcareous nannofossils. The base of the Ilerdian is poor in planktic microfossils and its precise correlation with the redefined Paleocene/Eocene boundary remains uncertain.