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The Paleogene greenhouse world comprises variable paleoclimate conditions providing an indispensable deep-time perspective for the possible effects of human-induced climate change. In this paper, paleotemperature data of the early Eocene climatic optimum (EECO) from the mid-latitude marginal marine Belgian Basin are discussed. They are derived from fish otolith δ18O compositions of four non-migratory species belonging to the families Congridae and Ophidiidae. Otoliths from several levels and localities within the middle to late Ypresian were selected. After manual polishing, bulk and incremental microsamples were drilled and analyzed by a mass spectrometer. A cross-plot of bulk otolith δ18O vs. δ13C results shows a discrepancy between both families used. Ophidiid data probably represent true bottom water temperatures of the Belgian Basin. The mean annual temperature (MAT) of the EECO is calculated at 27.5 °C, which is in line with other proxy results. However, variations in MAT up to 6 °C occur, suggesting a pronounced expression of climate variability in mid-latitude marginal basins. Incremental analyses revealed a ~9.5 °C mean annual range of temperatures, similar to modern seasonality. These results show that marginal marine environments such as the Belgian Basin are well suited to infer high-resolution paleoclimate variability. Open access journal ispartof: Geologica Belgica vol:14 issue:3 pages:143-157 status: published

A complex trace fossil that requires a three-dimensional (3D) reconstruction is described and interpreted. The specimens studied are assigned to a new ichnospecies (Hillichnus agrioensis) of Hillichnus Bromley et al., 2003. Most of them are uncollectable and a compound iconotype was designed to characterise the new ichnospecies. The three-dimensional trace fossil has been recorded in marginal-marine deposits close to the top of the Agrio Formation (Lower Cretaceous of Neuquén Basin, Argentina). The new ichnospecies shows a different pattern of feeding than H. lobosensis Bromley et al., 2003, and records defaecation downward in the deeper preservational level (level 4). Feather-like structures (level 2) that typify the ichnogenus also record the activity of an inhalant siphon and indicate a retractile movement. The vertical shafts (level 1) are scarcely recorded. Aligned double rings also document the infaunal habit of the tellinid bivalves that are considered the most likely producers of the trace. It is clear that when only level 2 is exposed, in some cases this form can be assigned to Jamesonichnites heinbergi Dam 1990a consequently, this ichnospecies is interconnected with more than one ichnogenus. Vertical projections recorded in branches differ from the type ichnospecies H. lobosensis Bromley et al., 2003. The occurrence in marginal-marine facies is congruent with the record of Jamesonichnites but not common in the type species and similar to those more frequent in deep-sea deposits (e.g. Polykampton alpinum Ooster, 1869). Fil: Pazos, Pablo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Fernández, Diana Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina

Graphoglyptids are diagnostic ichnofossils of the Paleodictyon ichnosubfacies (Nereitesichnofacies), which is well represented in deep-marine Mesozoic–Cenozoic thin-bedded turbidites. However, unusual shallow-water records of Mesozoic–Cenozoic Paleodictyon and particular preservational restrictions of graphoglyptid burrows introduce the question of whether graphoglyptids are reliable bathymetric indicators. We document and discuss another unusual graphoglyptid association preserved in shallow-marine, high-energy, organic-rich, and bioturbated turbidites of leveed channels in the upper middle Eocene CCa member, Cerro Colorado Formation, Fuegian Andes. The member includes the facies associations: 1) mudstones, 2) interbedded mudstones and thin-bedded Tbc turbidites, and 3) thick-bedded sandstones and mudstones. Facies association 3), interpreted as channel deposits, records at least three horizons with Desmograpton, Glockerichnus, Helicolithus, Helminthorhaphe, Megagrapton, Paleodictyon and Urohelminthoida. Associated beds are lenticular, channeled sandstone turbidites with marked basal erosion surfaces and variable proportions of interbedded mudstone-sandstone with high content of plant debris. Trace fossils in the channeled sandstones are dominated by Ophiomorpha rudis and O. annulata; mudstones within the thick-bedded mudstone-sandstone beds bear Nereites, Phycosiphon, Zoophycos and Paradictyodora, with subordinate Schaubcylindrichnus, Tasselia and Scolicia. The unusual preservation of limited graphoglyptid-bearing beds within a highly energetic and bioturbated interval seems to support the concept that preservational restrictions on graphoglyptid burrows could be locally more important than bathymetric constraints. Fil: Olivero, Eduardo Bernardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Lopez Cabrera O., Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Malumian, Norberto. Consejo Nacional de Investigaciones Científicas y Tecnicas; Argentina. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentina Fil: Torres Carbonell, Pablo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina

SimClast is a basin-scale 3D stratigraphic model, which allows several interacting sedimentary environments. We developed it from 2004 to 2008 at Delft University of Technology and implemented part of the Meijer (2002) code for accounting, loading and storing algorithms. SimClast is a fully plan view 2D, depth-averaged model, allowing the complex interaction between fluvial and wave influences on deltaic and shoreface development to be studied. It focuses on theoretical experiments, as quantitative experiments are intrinsically difficult to recreate in real world settings. Yet there lies the great strength of numerical modelling, as we can improve upon the understanding of these systems by focussing on the process forming and removing the deposits. The modelling applications focus especially on the erosional and nondepositional events as these probably represent the greatest amount of “stratigraphic time”. Short-term, high-resolution processes are coupled with the long-term stratigraphic model by nesting a parameterised version of the high-resolution processes. We extrapolate physical and empirical relationships of the geomorphological development and implement these. A necessary constraint on these long-term models is a relatively large grid sizing (i.e. km scale), as the area to be modelled is on the scale of continental margins and the modelling time is on the scale of many millennia. Areas of special importance are modelled by implementing sub-grid scale processes into a large-scale basin-filling model; this refines the model dynamics and the resulting stratigraphy. Processes included are; fluvial channel dynamics and overbank deposition, river plume deposition, open marine currents, wave resuspension, nearshore wave induced longshore and crosshore transport. This combined modelling approach allows insight into the processes influencing the flux of energy and clastic material and the effect of external perturbations in all environments. Many governing processes work on relatively small scales, e.g. in fluvial settings an avulsion is a relatively localised phenomenon, yet they have a profound effect on fluvial architecture. This means that the model must mimic these processes, but at the same time maintain computational efficiency. Additionally, long-term models use relatively large grid sizing (km scale), as the area to be modelled is on the scale of continental margins. We solve this problem by implementing the governing processes as sub-grid scale routines into the large-scale basin-filling model. This parameterization greatly refines morphodynamic behaviour and the resulting stratigraphy. SimClast recreates realistic geomorphological and stratigraphic delta behaviour in river and wave-dominated settings.

SimClast is a basin-scale 3D stratigraphic model, which allows several interacting sedimentary environments. We developed it from 2004 to 2008 at Delft University of Technology and implemented part of the Meijer (2002) code for accounting, loading and storing algorithms. SimClast is a fully plan view 2D, depth-averaged model, allowing the complex interaction between fluvial and wave influences on deltaic and shoreface development to be studied. It focuses on theoretical experiments, as quantitative experiments are intrinsically difficult to recreate in real world settings. Yet there lies the great strength of numerical modelling, as we can improve upon the understanding of these systems by focussing on the process forming and removing the deposits. The modelling applications focus especially on the erosional and nondepositional events as these probably represent the greatest amount of “stratigraphic time”. Short-term, high-resolution processes are coupled with the long-term stratigraphic model by nesting a parameterised version of the high-resolution processes. We extrapolate physical and empirical relationships of the geomorphological development and implement these. A necessary constraint on these long-term models is a relatively large grid sizing (i.e. km scale), as the area to be modelled is on the scale of continental margins and the modelling time is on the scale of many millennia. Areas of special importance are modelled by implementing sub-grid scale processes into a large-scale basin-filling model; this refines the model dynamics and the resulting stratigraphy. Processes included are; fluvial channel dynamics and overbank deposition, river plume deposition, open marine currents, wave resuspension, nearshore wave induced longshore and crosshore transport. This combined modelling approach allows insight into the processes influencing the flux of energy and clastic material and the effect of external perturbations in all environments. Many governing processes work on relatively small scales, e.g. in fluvial settings an avulsion is a relatively localised phenomenon, yet they have a profound effect on fluvial architecture. This means that the model must mimic these processes, but at the same time maintain computational efficiency. Additionally, long-term models use relatively large grid sizing (km scale), as the area to be modelled is on the scale of continental margins. We solve this problem by implementing the governing processes as sub-grid scale routines into the large-scale basin-filling model. This parameterization greatly refines morphodynamic behaviour and the resulting stratigraphy. SimClast recreates realistic geomorphological and stratigraphic delta behaviour in river and wave-dominated settings.

The UK has an obligation to monitor certain sites around its coastline due to various International environmental designations. Remote sensing is ideal as these areas are often difficult and hazardous to access. Traditionally, classification has been based on the spectral responses of targets, but indistinct spectral signatures between targets often leads to poor classification accuracy. To improve this, other methods of classification such as predictive spatial modelling (PSM) incorporate ‘knowledge’ of a study area in addition to the target’s spectral information. Well documented natural zonation of shallow marine habitats make them especially suitable for classification using PSM techniques. Using the ERDAS Knowledge Engineer, a series of knowledge-based rules relating to exposure, depth and substrate were tested, combined with QuickBird high spatial resolution remotely sensed data, to improve the classification of a study area in the Sound of Harris, Outer Hebrides, Scotland. Results show that after preliminary supervised classification based on spectral parameters, the additional rules enabled further subdivision of spectrally similar classes, and the simultaneous classification of both subtidal and intertidal biotopes in one process. This is an improvement on previous attempts which subset and separately classified the subtidal and intertidal areas. While the approach shows potential, considerable biotope confusion still exists, which resulted in a low overall accuracy of just under 40%. The need for further discriminating factors to improve the classification, as well as a more robust knowledge based approach, are highlighted as potential future improvements.

Dispersive Scholte waves as well as acoustic guided waves have been excited by surface towed airguns and recorded with stationary receivers (OBS) and a towed hydrophone array. The inversion of the recorded wavefield spectra was adapted to the data from shallow marine environments. The dispersive interface wave travelling along the sea floor (Scholte Wave) is sensitive to the shear wave velocity (Vs) of the sediment and could be sucessfully recorded and inverted at different sites in Kiel Bay and the south-east rim of the Arkona Basin in the Baltic Sea. Limitations remain for very soft sediments with Vs < 50m/s. The acoustic guided wave is sensitive to density and compressional velocity (Vp) as well as Vs. Shear wave velocity and high resolution Vp information could be obtained from the inversion of this wave type in the central Arkona Basin, where very soft sediments (10-20m) overlaid the till and chalk layers, and no interface wave was observed. The lateral variation of the dispersion of Scholte waves was observed with the towed acquisition system, which could be suitable to effciently locate areas with a high shear wave velocity basement at shallow (0-100m) depth.

The Lower Palaeozoic sedimentary cover of the Tandilia (Balcarce Formation) is made up of thick quartz arenite beds together with kaolinitic claystones and thin fine-grained conglomerates. The Balcarce Formation was formed in the nearshore and inner shelf environments of a tide-dominated and storm influenced open platform. It shows many features suggesting tidal sedimentation. Coarse-grained facies were formed by sand bar migration and accretion. Heterolithic packages are interpreted as interbar (swale) deposits. Subordinated HCS sandstones indicate storm events. The recognition of thick progradational clinoforms allows to confirm that the Balcarce sea was open to the south, as suggested years ago through palaeocurrent interpretation. The great abundance and variety of trace fossils is among the most outstanding characteristics of this unit. The ichnotaxa that have been recognised so far are: Ancorichnus ancorichnus, Arthrophycus alleghaniensis, Arthrophycus isp., Bergaueria isp., Cochlichnus isp., Conostichus isp., Cruziana furcifera, Cruziana isp., Daedalus labeckei, Didymaulichnus lyelli, Didymaulichnus isp., Diplichnites isp., Diplocraterion isp., Herradurichnus scagliai, ?Monocraterion isp., Monomorphichnus isp., Palaeophycus alternatus, Palaeophycus tubularis, Palaeophycus isp., Phycodes aff. pedum, Phycodes isp., Plagiogmus isp., Planolites isp., Rusophycus isp., Scolicia isp. and Teichichnus isp. Trace fossils have traditionally been used to assign the Balcarce Formation to the Lower Ordovician, due to the presence of Cruziana furcifera. However, Plagiogmus is typical of Cambrian successions world-wide.

The Lower Palaeozoic sedimentary cover of the Tandilia (Balcarce Formation) is made up of thick quartz arenite beds together with kaolinitic claystones and thin fine-grained conglomerates. The Balcarce Formation was formed in the nearshore and inner shelf environments of a tide-dominated and storm influenced open platform. It shows many features suggesting tidal sedimentation. Coarse-grained facies were formed by sand bar migration and accretion. Heterolithic packages are interpreted as interbar (swale) deposits. Subordinated HCS sandstones indicate storm events. The recognition of thick progradational clinoforms allows to confirm that the Balcarce sea was open to the south, as suggested years ago through palaeocurrent interpretation. The great abundance and variety of trace fossils is among the most outstanding characteristics of this unit. The ichnotaxa that have been recognised so far are: Ancorichnus ancorichnus, Arthrophycus alleghaniensis, Arthrophycus isp., Bergaueria isp., Cochlichnus isp., Conostichus isp., Cruziana furcifera, Cruziana isp., Daedalus labeckei, Didymaulichnus lyelli, Didymaulichnus isp., Diplichnites isp., Diplocraterion isp., Herradurichnus scagliai, ?Monocraterion isp., Monomorphichnus isp., Palaeophycus alternatus, Palaeophycus tubularis, Palaeophycus isp., Phycodes aff. pedum, Phycodes isp., Plagiogmus isp., Planolites isp., Rusophycus isp., Scolicia isp. and Teichichnus isp. Trace fossils have traditionally been used to assign the Balcarce Formation to the Lower Ordovician, due to the presence of Cruziana furcifera. However, Plagiogmus is typical of Cambrian successions world-wide., Facultad de Ciencias Naturales y Museo

A section equivalent to the Pliocene La Portada Formation exposed in the coastal cliff at Hornitos, northern Chile, contains a ca. 7-10 m thick conglomerate bed. The bed occurs within a succession of shallow marine sandstones and has an erosional contact with underlying strata. The largest boulders of basement (5 m) are angular to very angular and are set within a matrix of very poorly sorted fine to very coarse grained shell-rich sandstone. Also present are very well rounded granodiorite pebbles and shallow marine sandstone intraclasts (maximum 10 m). The clast size, erosional contact, associated facies and bed thickness suggests that the conglomerate bed is a shallow marine tsunami deposit. The angular clasts indicate limited transport and no marine reworking prior to deposition. They represent alluvial fan sediment incorporated into the bed during tsunami backflow. Intraclasts of shallow marine sandstone are thought to have been ripped up and included in the bed during the seaward passage of the tsunami across the shoreface Un posible depósito de tsunami Plio-Pleistoceno, Hornitos, norte de Chile. Una sección equivalente a la Formación La Portada de edad pliocena, expuesta en el acantilado costero en el sector de Hornitos, norte del Chile, expone un estrato de conglomerados de ca. 7-10 m de potencia. El estrato ocurre dentro de una sucesión de areniscas marinas someras y tiene un contacto de erosión con los estratos infrayacentes. Los clastos mayores (5 m) de basamento son angulares a muy angulares y se emplazan en una matriz arenisca de grano fino a muy grueso, pobre a muy pobremente seleccionada y con abundantes conchas. También están presentes clastos bien redondeados de granodiorita junto a intraclastos de areniscas marinas someras. El tamaño de los clastos, el contacto erosional, las facies asociadas y la potencia del estrato sugieren que el estrato de conglomerados es un depósito marino somero correspondiente a un tsunami. Los clastos angulares indican un transporte limitado sin retrabajo marino con posterioridad a su depositación. Ellos representan sedimentos de un cono aluvial incorporados al estrato durante el flujo de retroceso del tsunami. Los intraclastos de la arenisca marina somera se consideran que son producto de la erosión e inclusión en los conglomerados durante la etapa de avance del tsunami a través de la zona de anteplaya.

Se estudian cualitativa ycuantitativamente las asociaciones micropaleontológicas recuperadas de afloramientos del Cuaternario de la cuenca del Salado y zonas aledañas. Los análisis cualitativos involucran ladeterminación sistemática de las asociaciones de ostrácodos y foraminíferos y, en algunos casos, sucaracterización tafonómica. Los estudios cuantitativos comprenden diversos análisis de la riqueza yla diversidad de las asociaciones, la confección del Diagrama Triangular de Subórdenes paraforaminíferos bentónicos y el Diagrama de Frecuencias Acumulativas, que refleja la estructurapoblacional, en ostrácodos. En forma adicional, se realizó un Análisis de agrupamiento con el fin deconfirmar los resultados obtenidos por métodos cualitativos y cuantitativos. Los datos obtenidos, sumados a evidencias de campo, permiten caracterizar lospaleoambientes marinos establecidos en el Nordeste de la provincia de Buenos Aires durante el Cuaternario. Para la Formación Pascua (Pleistoceno medio) se propone un paleoambientecorrespondiente a un sistema de islas de barrera/laguna costera asociado a un momento de mar alto. Para la Formación Destacamento Rio Salado (Pleistoceno superior?-Holoceno inferior) se proponeun paleoambiente correspondiente a un estuario parcialmente cerrado o bien una laguna costera,asociado al inicio de la transgresión representada por el Piso Platiano (= Querandinense de algunosautores). Para la Formación Las Escobas (Holoceno), se propone un paleoambiente complejo,relacionado con un sistema de islas de barrera/laguna costera, la edificación de cordones litorales yfacies terminales pantanosas, correspondiendo a la fase regresiva del Piso Platiano. Micropaleontological analyses, both qualitativeand quantitative combined with field data, provide the basis for a paleoecological study of Late Quaternary outcrops located at Salado basin, northeastern Buenos Aires province. Ostracoda and foraminiferal assemblages were taxonomically and some of themtaphonomically characterized. Furthermore diversity, richness, Triangular Plot of Suborder ofbenthic foraminifers and age population structure in ostracodes were calculated. Additionally,clusters analyses were made so as to infer affinities and correlations. The Late Quaternary shallow marine sequences of Salado basin were palaeoenvironmentallycharacterized with microfossil contents and field data, such as litology and structures. Consideringthem we can suggest that Pascua Formation (Middle Pleistocene) is closely related with a barrierisland/lagoon system associated with the pleistocene sea level rise. Destacamento Río Salado Formation (Upper Pleistocene?- Holocene) is associated with a partially-closed estuary or lagoonalestuary, which has a free connection with the open sea, and it represents the transgressive fase of the Platian Stage. Las Escobas Formation (Holocene) represents a high energy barrier island/lagoonsystem, a mainland-attached barriers complex with mixohaline salinities on a wave-dominated coastand finally the filling phase of a lagoon, such as a marsh. It is related with the regresive fase of Platian Stage and active coastal progradation. Fil: Laprida, Cecilia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.

Knowledge of basic data variability is essential for the interpretation of any proxy-based paleotemperature record. To evaluate this for δ18O stable isotope paleothermometry based on early Paleogene fish otoliths from marginal marine environments, an intra- and interspecific stable O and C isotope study was performed at a single locality in the southern North Sea Basin (Ampe Quarry, Egem, Belgium), where shallow marine sands and silts are exposed. The age of the deposits is early late Ypresian (ca. 50.9 Ma) and falls within the early Eocene climatic optimum (EECO) interval. In each of four fossiliferous levels sampled, the same three otolith species were analyzed (Platycephalus janeti, Paraconger papointi and “genus Neobythitinorum” subregularis). Intrataxon stable isotope spread amounts on average 2.50-3.00‰ for all taxa and is present in all levels. This implies that each sample level comprises substantial variability, which can be attributed to a combination of temporal and taphonomic effects. More importantly, intertaxon offsets of 4.60‰ in δ13C and 2.20‰ in δ18O between the mean values of the three otolith species are found, with “N.” subregularis representing more positive values relative to the other species. We hypothesize that freshwater influence of coastal waters is the most likely cause for these discrepancies. Similar analyses on two coastal bivalve species (Venericardia sulcata and Callista laevigata) corroborate this hypothesis. Accordingly, δ18O values measured on “N.” subregularis otoliths probably represent a more open oceanic signal, and therefore seem well-suited for δ18O stable isotope paleothermometry. This study highlights the importance of investigating data variability of a biogenic carbonate paleotemperature proxy at the species level, before applying paleotemperature equations and interpreting the outcome. ispartof: Austrian Journal of Earth Sciences vol:105 issue:1 pages:200-207 ispartof: location:Salzburg status: published