Thématiques et Sessions > All sessions

Session 1.1. Digital outcrops: new methods to study sedimentary outcrops

Conveners: Aurélien Bordenave, Raphaël Bourillot, Emmanuel Dujoncquoy, Sophie Leleu, Benoit Issautier

The session "Digital outcrops: new methods of analysis of sedimentary outcrops" aims to bring together new research based on the acquisition, visualization and interpretation of digital outcrops in order to analyze them from a sedimentary point of view both in 2D and 3D. New acquisition technologies (airborne, towed, tripods or drone) allow the acquisition of a wide variety of new data: photogrammetric, lidar, radar, hyperspectral, magnetic or electromagnetic. These data are fundamental to the characterization, at high resolution, of the architecture of sedimentary systems. In particular, they allow access to a wide range of information (lithologies, fracturing, paleocurrent, architecture of sedimentary bodies...), through qualitative, quantitative, semi-automatic, automatic or even innovative methods such as artificial intelligence. In addition, new visualization technologies such as virtual reality or augmented reality offer new observation capabilities, not accessible in the field (close-up bird's eye view, accessibility to a coastal cliff, overlay of information at 1:1 scale). Thus, all these approaches coupled with a naturalistic field approach allows us to propose geological models representing the architecture of sedimentary systems: (i) in their current form (3D modeling) or (ii) in a format that evolves with time (4D modeling).

Session 1.2. GIS as a tool for research in Geosciences

Conveners: Vincent Hanquiez, Nina Tanguy, Mathilde Pitel-Roudaut

Used on an ad hoc basis in the early 2000s, Geographic Information Systems (GIS) make it possible to collect, organize, manage, analyze, share and represent geographic data. They have since been democratized in the field of geosciences, where they have become an essential and relevant tool, notably due to the strong potential of spatial analyses, the cross-referencing of transdisciplinary data and the cartographic approach. At each of these stages, the quality of the geographic data remains essential to meet the needs of scientific interpretation. This session, with a technical and scientific vocation, is intended to be a place of exchange and confrontation of practices resulting from the use of GIS in geosciences.

Session 2.1. Paleoenvironments and dynamics of human settlement

Conveners: Axel Ehrhold, Pierre Stéphan, Aurélie Penaud, Pascal Le Roy, Serge Suanez, Ronan Bourgaut, Yves Pailler, Clément Nicolas, Yves-Marie Paulet

This session proposes, under the impetus of Theme 4 of the Brest Iroise Workshop Area (ZABrI), the UBO ArMeRIE Chair (Maritime Archaeology and Interdisciplinary Environmental Research) and the SeaLex project of the EUR Isblue, to develop topics related to interdisciplinary research on past and future trajectories of socio-ecosystems based on retrospective analyses (sedimentological, geomorphological, paleoecological, sclerochronological, archaeological, historical) of sedimentary archives at the Pleistocene-Holocene scale. Among the stated objectives of this session are expected papers related to:(i) the understanding of interactions between human groups and their environments in a broad sense, whatever the geographical area and the type of archive (e.g. lacustrine, fluvial, marine or coastal) studied. Here, the central question concerns the impact of anthropic activities on the sedimentary evolution of the systems examined and more broadly on the evolution of natural landscapes, in relation to the impacts of deforestation, soil erosion, geomorphological modifications, etc. (ii) the question of the capacity of societies to adapt to short or long term environmental changes, in particular in the face of the challenges of rising sea levels and the effects of disruptive sedimentary dynamics. (iii) the methodological and conceptual challenges of studies that seek to decipher the relationships between natural environmental dynamics and human occupation dynamics based on sedimentary archives: how to reconcile the concerns of scale (spatial and temporal) when seeking to parallel the "social" and "ecological" components of socio-ecosystems?

Session 2.2. Underwater geoarchaeology: Combined approach of sedimentology and geophysics to characterize underwater archaeological sites

Conveners: Guillaume Jouve, Christophe Benech, Jean-Philippe Goiran, Gilles Brocard

The characterization of underwater archaeological sites by geophysical instrumentation (sediment sounders, sidescan sonars, multibeam sounders, magnetometers, etc.) in continental and marine environments allows the discovery of new sites of interest, to propose three-dimensional models of past anthropic environments, as well as to understand the evolution of environmental systems from the archaeological period considered to the present. It requires however the combination with sedimentological analyses from in situ cores (malacology, granulometry, elemental and organic geochemistry, mineralogy, etc.) in order to establish the geophysical signature of the characterized environments and to propose robust scenarios as to the origin and evolution of the natural systems integrating these archaeological sites. This session therefore invites interdisciplinary and/or multidisciplinary research in geoarchaeology involving this methodological approach, but not strictly limited to it, and whose applications in archaeology can be extended to all civilizations and on all continents.

Session 3.1. Diagenesis and organic/inorganic authigenesis

Conveners: Nicolas Tribovillard

Sedimentation is inseparable from the transformations that accompany or modify the sedimentary message. These transformations can affect the organic or mineral fractions of the sediments. Some reactions are induced by the organic fraction and impact the mineral fraction. Bacteria and archaea are essential factors. This session is an opportunity to review recent knowledge on this multi-faceted topic.

Session 3.2. Retroactive effects of carbonates (production and alteration-karstification) on climate, sea level and the carbon cycle

Conveners: Jean Borgomano, Stephan Jorry

Variations in the volume of carbonates produced on low-latitude continental shelves, banks and isolated platforms, as well as those exported to ocean basins, are known to be highly dependent on the size of the re-flooded surfaces during deglaciation periods. The retroactive effects, in particular on climate, are still highly debated in the scientific community. This session aims to bring together the results of research on carbonate systems, focusing on topics such as seismic stratigraphy, geodynamic cycles and bioproducer evolution, at different time scales. This session could include several topics including the "reef-karst effect" on past climate change and impacts on atmospheric CO2, links between carbonates, resources and the energy transition, and carbonates of the future in response to climate change and sea level rise. Work on modeling marine carbonate systems from the global scale to the case study could also be presented.

Session 3.3. Precambrian Sediments and Microbialites: Archives of Biological, Chemical and Tectonic Evolution of the Earth System

Conveners: Stefan Lalonde, Pierre Sans-Joffre, Christophe Thomazo

Sedimentary archives record more than 3.5 billion years of evolution of the Earth system. This session invites contributions that draw on sedimentological, stratigraphic, mineralogical, chemical, microbiological, paleontological and experimental data to decipher the diverse information preserved in the sedimentary record of the early Earth. Studies of recent and modern sedimentary systems that represent analogues of the characteristic early Earth sedimentary systems, such as microbialites and chemical sedimentary deposits, are also welcome. The ultimate goal of this session is to better understand the evolution of physico-chemical conditions, the presence and activity of (micro)-biological fauna, and the impact of the onset of plate tectonics on the surface environments of the early Earth through the study of ancient sedimentary records and their analogues.

Session 4.1. Sedimentology and georessources

Conveners: Geoffray Musial, Christophe Rigollet, Olivier Parize, Laurent Gindre

Climate change and the energy transition which are taking place, lead to a need for evaluation and valorisation of geological resources. In what sedimentological, stratigraphic or diagenetic context can we find the elements that will be exploited in the future? How to preserve or store them? From native hydrogen to conventional ores, rare earths or carbonaceous resources, the objective of this session is to promote the use of sedimentology in georesource prospecting, geothermal energy or greenhouse gas sequestration.

Session 4.2. Applications of trace fossils and ichnofabrics in sedimentological and stratigraphic studies

Conveners: Geoffray Musial, Jean Gérard

The integration of fossil traces in sedimentological and stratigraphic studies is a complementary tool to facies analysis for the characterization of sedimentary deposits. This session will present applications of ichnology for the determination of depositional environments, characterization of stratigraphic surfaces and pore network properties, which are key to understanding the distribution of geological resources, in particular the recognition of drains and barriers to fluid flow. Case studies will illustrate the identification of ichnotaxons, their distribution within sequences and along major stratigraphic surfaces, and their associations in ichnofabrics.  These applications, ranging from continental to deep-sea, will show the decisive character of the study of fossil traces in the resolution of sedimentary problems.

Session 5.1. The Messinian salinity crisis: sedimentological consequences

Conveners: Jean-Loup Rubino, Damien Do Couto

The Chronology of the Messinian Salinity Crisis is now remarkably constrained, it is therefore time to focus in more detail on the multiple sedimentological consequences of this crisis beyond the only deep or marginal evaporites that constitute its "flag". We will thus be interested in the synchronous deposits of the crisis itself as well as the post-crisis Pliocene deposits. The former include carbonates, evaporites and all clastic systems recording the fall phase and the low level sensu stricto. The latter, often of unusual dimensions, fill a gigantic network of incised valleys and include, among others, the Gilbert deltas which participate in the filling of the rias. We also find more and more often tidal evidence in this filling while the tidal range in the Mediterranean is very low. This sedimentological diversity on the Mediterranean rim will be the focus of this session.

Session 5.2 "evaporites and hypersaline systems"

Conveners: Laurent Gindre, Alexandre Pichat

This session aims at anchoring the sedimentological, stratigraphical, structural, geochemical and geodynamic studies that focus upon the present-day or ancient evaporitic basins but also the pre-Salt/Salt and Salt/post-Salt transitions. Accounting for the spatio-temporal evolution of hypersaline depositional systems urge for a multi-disciplinary integration that ultimately enables to obtain a relevant interpretation of primary to secondary facies and approach the hydrological composition of the parenthood brine. Climatic variations, sea-level fluctuations, hydrothermalism, recycling processes, tectonism or even syn-depositional halokinesis can be considered as main control factors of salt deposition and by extent potash occurence. The awaiting contributions may englobe all these criteria from local to basin scale, enabling to respond to scientific challenges ranging from intra-salt  organic matter enriched shale, mineral ressources, geohazards related to saline cavities, geophysical anomalies or well tying, etc....

Session 6.1. Geomorphological and sedimentary record of glaciations

Conveners: Pierre Dietrich, Alexis Nutz, Samuel Toucanne

During glaciations, ice masses profoundly affect all continental surfaces and landscapes as well as land and sea sedimentary basins, from intracontinental landforms to continental shelf edges and slopes, and induce eustatic variations of very large magnitudes. Indeed, during glacial phases, erosion and landform shaping are the source of large volumes of sediments that are then transported, possibly stored temporarily in intermediate depocenters, and finally deposited in sedimentary basins (sink). It is the analysis of these morphosedimentary archives in the different compartments of this specific sedimentary cycle that allows us to reconstruct past glacial dynamics and their impacts on continental surfaces and sedimentary basins. While the influence of the last glacial cycle on landscape shaping and on land and sea sediment dynamics is relatively well constrained, these dynamics in response to glaciations at larger spatial and temporal scales (pre-LGM cycles, pre-Quaternary and pre-Cenozoic glaciations) remain largely unquantified, and many questions remain: What is the influence of repeating high-frequency glacial periods on landscape shaping and on sediment stock production, transport and deposition? What are the similarities and/or differences between the Cenozoic glaciation and the "ancient" glaciations of the Earth? This session aims to present the state of knowledge on the interactions between glacial dynamics, surface dynamics and sediment dynamics through studies of sedimentology, stratigraphy, geomorphology, geochemistry, source tracing, numerical modelling etc. Particular emphasis will be placed on "source to sink" studies aiming at the integration in a spatio-temporal continuum of eroding, transferring and depositing glacial domains.

Session 6.2. Surface Geochemistry tools for constraining Climate change

Convener: Anne Trinquier

Geochemistry is a powerful toolbox for reconstructing Earth surface processes and environmental changes, including erosion, weathering, (bio-) geochemical cycles, diagenesis, biomineralization, and ocean circulation, while, concomitantly, constraining their rates and chronologies. We welcome contributions on analytical and experimental geochemical strategies (including, but not limited to, high-resolution imaging, mass spectrometry, modelling), that can help draw links between paleoclimate records, present-day Earth surface processes and global Climate change.

Session 6.3. Paleoclimatic and paleoenvironmental reconstructions in the Quaternary

Conveners: Charlotte Skonieczny, Pierre Sabatier, Vivianne Bout-Roumazeilles, Pierre Antoine

This session aims to document Quaternary climatic and environmental changes reconstructed from the study of sedimentary archives. These natural archives can be oceanic (coastal and deep sediments) or continental (lake sediments, peat bogs, loess...) and originate from low, middle or high latitudes. Single and multi-tracer approaches, both biogenic, terrigenous, organic or inorganic are welcome. The proposed reconstructions can cover time windows ranging from orbital to historical scales and are based on themes such as: (i) the identification of climate oscillations at different time scales, (ii) the response to external forcings (orbital variations, solar and volcanic forcings), (iii) the role of the ocean and couplings of the ocean-atmosphere-cryosphere system, (vi) inter-hemispheric and high-low latitude teleconnections (monsoon system), (v) mechanisms involved in rapid variability changes such as extreme events and in abrupt climate shifts. This session, which is deliberately spatially and temporally broad, aims to emphasize the crucial importance of properly constraining the sedimentary context of an archive in order to propose robust paleoclimatic and paleoenvironmental reconstructions.

Session 7.1. Source to Sink studies and continental surface dynamics

Conveners: Cécile Robin, Delphine Rouby, Marina Rabineau, Sébastien Castelltort, Emmanuelle Pucéat

The Earth's surface is today the domain of complex interactions between humans and their physical, chemical and biological environment, including sediments. These sediments have been produced, transported and deposited on the Earth's surface over geological time. These sediments contain geological resources or can be a storage for various human wastes (CO2, nuclear, chemical) which are of primary importance for the development of humanity. It is therefore of primary importance to better predict the location, structures (heterogeneities) of sediments and their mineralogical/physical properties (particle size distribution, porosity, permeability, etc.). The Source to Sink approach responds to this challenge by characterizing all the processes of physical and chemical erosion in source areas, transfer and storage of sediments in sedimentary basins, processes controlling the dynamics of continental surfaces. In this session, field studies, numerical or experimental, devoted to erosion, transport and deposition mechanisms and their internal and external forcing, including anthropogenic, will be presented through their geomorphological, sedimentological, stratigraphic or geochemical characterization. Contributions at all temporal and spatial scales are welcome, as well as the implications of these Source to Sink studies in terms of landscape evolution, prediction of sand resources and their reservoir qualities, paleohydraulics or control of biogeochemical cycles and their climatic implications.

Session 7.2. Lake deposits

Conveners: Emmanuelle Vennin, Mathieu Schuster, Youri Hamon

Among continental environments, lacustrine sedimentary basins occupy a special place because they preserve archives of the history of our planet, of its ecosystems and of humanity, both over long periods and with a very high temporal resolution. These archives can be presented through a characterization of facies, depositional environments, geometries and morphologies that constitute clues for the spatio-temporal reconstruction of the evolution of lakes. Lakes are often the site of mixed carbonate-clastic, organic and evaporite sedimentation, thus allowing to trace changes in erosion, weathering, productivity and watershed hydrology over time, but also to constrain physico-chemical and biological changes in lakes. This session could document the records of sedimentation control parameters in the lake domain with respect to the role of climate, geodynamic context and watershed physiography using data acquired in the field, by analogy and experimentation or by numerical simulations. It aims to be integrative, involving researchers from different disciplines of stratigraphy, sedimentology, tectonics and paleontology. The contributions can extend to all geological periods, from deep time to recent changes, notably linked to the impact of anthropic activities, and why not bring a perspective on the future of lakes. They can cover all spatial and temporal scales leading to records of short and long duration.

Session 7.3. Impacts of human activities on the critical zone within continental and coastal domains: retro-observation using sedimentary archives

Conveners : Jérôme Goslin, Yoann Copard, Maxime Debret, Laurent Dezileau, Brice Mourier, Pierre Sabatier, Bernadette Tessier

Within the critical zone, sedimentary crisis and contaminants (heavy metals, organic pollutants, microplastics) which go along human activities are preserved in the sedimentary deposits of the continental, estuarine and coastal environments. Hence, scrutinizing sedimentary archives allows (i) the production of historical chronologies of perturbations for periods during which the impacts of human activities on the environment were not monitored, (ii) the identification of perturbation thresholds and (iii) the reconstitution of pre-industrial and/or ante-perturbation reference states. Approaches using retro-observation from the sedimentary archives are thus crucial for analyzing the effects human activities - as well as their cumulation - have on natural environments and on the ecosystems they support, along different spatio-temporal scales and in conjunction with natural climatic variability. This session calls for studies studying pressures and impacts induced by human activities on continental (fluvial and lacustrine) and coastal (estuarine, marshes, subtidal domains) environments using sedimentary archives within a source-2-sink approach. It will welcome reconstructions of perturbation chronicles along the last centuries, as well as works concerning problematics linked to the archival of these within the sediments, dating as well as innovative tracing approaches. A particular emphasis will be put on incorporating studies trying to understand cumulative effects and deconvoluting signals. Will also be welcomed proposals dealing with modelling, placed at the interface with life sciences or the management of natural areas.

Session 7.4. Event deposits: processes and products from experiments to observations

Conveners: Eric Chaumillon, Sophie Hage, Pierre Sabatier

Extreme climatic events (floods, cyclones, avalanches, glacial breakup...) or geodynamic events (earthquakes, tsunamis, volcanic eruptions, landslides) are of major interest, given their strong and long-lasting impacts on ecosystems and societies. In the context of climate change, some extreme events are modified in terms of timing and spatial extension. The study of extreme events is a major challenge because their measurements are rare, often incomplete and limited in time. Sedimentology can help to better constrain these events, particularly through the estimation of return times, triggering mechanisms and deposition in the past. We propose a transversal session that will gather researchers in sedimentology working on various event deposits (tsunamis, cyclones, floods, avalanches, earthquakes, landslides...) and in different settings (marine, coastal, lake, river...). We invite contributions using complementary approaches (sediment archives, processes, post-disaster measurements, physical measurements, modeling, etc) that can help to reconstruct the history of extreme events. Attention can also be paid to i) influence of an event on the record of other types of events and ii) the impact of these events on the carbon cycle and biogeochemical fluxes that govern ecosystems and climate.

Section 8.1. Bottom currents and their products in contourite depositional systems

Conveners: Emmanuelle Ducassou, Thierry Mulder, Vincent Hanquiez, Paul Moal, Nathalie Babonneau, Viviane Bout-Roumazeilles

Bottom currents are critical processes of the global thermohaline circulation regulating Earth climate. This deep circulation includes currents related to geostrophic and thermohaline circulation, internal waves, slope currents such as up/downwelling, cascading or deep gyres. These currents shape significantly the sea floor with erosive features, transport, reworking and specific deposits named contourite drifts. However, there is a lack of understanding in detail of these marine processes and their related contourite deposits.This session integrates bottom current circulation, sedimentary processes but also deposits and their implication on paleoceanographical reconstructions. This would allow to address the role of oceans in the global climate system, to consider contourites as a new target for economical ressources, and to identify the specific biota and deep marine ecosystems related to circulation of deep currents. This session is thus multidisciplinary and open also to lacustrine drifts, including the following questions/issues: (1) Sedimentology of contourite deposits : morphology, geometry, facies (hiatus, contourite depositional systems, etc.) and paleoceanographical reconstructions, (2) Fossil contourites : issues, identification and paleoceanographical significance, (3) Water mass circulation and bedforms : flow of bottom currents surroundings barriers, variability induced by internal waves and benthic storms, (4) Coupling of oceanographical, sedimentary and biological processes, (5) Interactions between turbidite and contourite systems, (5) Relevance and economical importance of contourites (mineral and energetic ressources), or (6) Technological and methodological advances in studies of contourites.

Session 8.2. Architecture and depositional processes associated with wave sediment

Conveners: Christian Gorini, Julien Bourget, Thierry Mulder, Jean-Loup Rubino

Sediment waves are becoming one of the most common large sedimentary structures in the subaqueous environment from the deep domain (contour ripples, turbidic levees or turbidic lobes), to the pro-deltas at very low bathymetries, or even covering large areas on continental slopes. This session is dedicated to review the state of the art on these structures and in particular to complete the inventory of their depositional areas, to better define their variability and especially to try to address the difficult issue of hydrodynamic processes at the origin of these structures.

Session 8.3. Deep-water sedimentation : processes, products ans sediment architecture : Ttribute to Bruno Savoye

Conveners: Nathalie Babonneau, Bernard Dennielou

This session aims at gathering the results of research works in marine sedimentology on gravity sedimentation in the deep marine domain, and in particular on turbidic systems. From a thematic point of view, this session proposes to cover both work on: (1) the sedimentary architecture and the understanding of the factors forcing this architecture; (2) the sedimentary facies and their interpretation in terms of process, source and trigger; (3) the measurement of current gravity flows and their contribution to the understanding of the dynamics of these environments; and up to (4) the modeling of these processes for the physical characterization of sediment transport. Bruno Savoye was a researcher in the Marine Geosciences Department of Ifremer. He left us suddenly in 2008 and devoted a large part of his career to the study of turbidic systems. He was very active in the ASF, involved in the office of the association and in the organization of the ASF Congress in Brest in 1991. He has worked on many geographical projects and has initiated many oceanographic campaigns. In particular, he has led large exploratory projects in collaboration with industry. Among his main geographical projects, we can mention his actions on the Congo margin (Congo turbidic system), the Ligurian margin (Var sedimentary system), the East-Corsican basin (Golo), the submarine slopes of Reunion Island, the Algerian margin, the turbidic system of the Amazon... He has trained numerous PhD, Master and engineering school students, and conducted his projects with numerous collaborators at Ifremer, in academia, and in industry, in France and abroad. His scientific legacy on underwater gravity sedimentation is vast. In this session, we invite you to present work on gravity processes and deposition in the deep sea, and thus in some continuity with the work of Bruno Savoye. This concerns of course researchers, former students and collaborators of Bruno, but also all researchers and students working on these research topics.

Session 9.1 Sedimentation on continental slopes during deformation (compressive/extensive)

Conveners: Tarik Kernif,Thierry Nalpas, Sophie Leleu, François Fournier

The continental slopes created during deformation undergo various gravity processes recorded in the sedimentary deposits and displaying early diagenetic transformations. To what extent do the sedimentary dynamics of continental slopes give information on the geodynamic processes of lithospheric deformation? How important are the types of slope deposits and their diagenetic evolution for (i) the prediction of reservoirs and mineralization associated with these deposits, and (ii) the prevention and consideration of gravity and landslide hazards? This session aims to get contributions concerning gravity-dominated sedimentation in divergent or convergent tectonic settings, in recent or ancient siliciclastic or carbonate aerial or subaqueous depositional environments of continental slopes. All approaches can find their place in this session, on all aspects of field and/or laboratory work, using advanced petrographic and diagenetic methods (e.g., cathodoluminescence, SEM...), geochemical (e.g., δ13C, δ18O...) or geochronological (e.g., U-Pb dating by LA-ICP-MS...) as well as analog and numerical modelling of objects or processes.

Session 9.2 Understanding fluid systems, geohazards and societal issues

Conveners: Lies Loncke, Antonio Cattaneo, Vincent Riboulot

Continental margins and basins are domains of genesis and circulation of fluids (gas, oil, water) that have an important role in the generation of hazards (e.g. sedimentary instability, tsunami, ocean acidification, global warming). This session will focus on identifying and understanding fluid-related processes from their generation in sediments to their dispersion in the hydrosphere or atmosphere, including their impact on sedimentary processes and their possible storage as gas hydrates.

Session 9.3: Sedimentation and transport processes around volcanic islands – from their evolution record to risks assessment.

Conveners: Fabien Paquet, Benoît Caron, Elodie Lebas, Jean-Luc Le Pennec, Stéphan Jorry

Sedimentation around volcanic islands records their evolution, from growth on the seabed and emersion, to later erosional stages and weathering. Studying sedimentary successions along the submarine flanks down to the abyssal plain allow for defining the main phases of their evolution as along with occurrences of major catastrophic events (eruptions, slope instabilities and flank collapses), or interaction with environmental processes (climate, oceanic currents, etc.). Identifying, characterizing, and dating past events offer a knowledge on their parameters, recurrence time, and prove useful for volcanic, seismic and instability risks assessment. Recent events in Indonesia, Italy, Mayotte, and Tonga recall the importance to fine tune the geological knowledge of oceanic volcanic edifices to support and design the monitoring tasks and duties.We hence invite you to present your research focusing on sedimentation and transport processes around volcanic islands and/or submarine volcanic edifices. Presentations may focus on the understanding of volcanic edifices evolution, specific sedimentary features or processes, records of catastrophic events, geotechnical studies of potentially unstable slope deposits, and on the contribution of basin studies in the risk and hazard assessment task. Presentations with review or methodological scopes are also welcomed.

Session 9.4: Mantle@Mud

Conveners: Daniel Aslanian, François Guillocheau

The evolutionary cycles of our planet Earth, its changing morphology, and the oceanographic and climatic fluctuations that we observe, are intimately linked to deep processes, whatever the time scale considered. Thus, the evolution of continental and oceanic spaces generates regional modifications that are strongly coupled to atmospheric and oceanic dynamics and to the climatic variations, past or future, that result from them. Understanding our planet Earth and modelling its past and future evolution therefore requires an understanding of this link between the deep and the surface, between the geosphere, the biosphere, the hydrosphere and the atmosphere, and requires an inter- and transdisciplinary, holistic approach. In this complex system, the place of sediments is singular in more than one way: resulting from erosion, they are the result of the combination of climatic and relief variations. Mostly transported via the river system to the deep ocean basins, they allow the recording of tectonic movements and environmental variations on the continent, the formation of the margins and oceans and their associated movements and finally the eustatism. We propose here to approach the sediment as a revealer, both counter and storyteller of this deep geodynamics.

Session 9.5. Tecto-sedimentary session

Convener: Philippe Razin, Eric Lasseur

This session of the ASF is dedicated to the presentation of research works concerning the recording of tectonic deformations in sedimentary series. The aim is to illustrate the impact of deformation on both the geometry of deposits and the distribution of facies at different time and space scales. The presentations can thus concern local studies with a thematic vocation as well as regional syntheses on the scale of sedimentary basins. Emphasis will be put on stratigraphic and sedimentological criteria allowing to characterize the amplitude, the wavelength and the speed of deformations in different geodynamic and structural contexts (rifts, passive/active margins, intracontinental basins, basins with saliferous tectonics, etc.). The idea is to recall to what extent sedimentology provides valuable and essential information for the interpretation of geological objects.

Session 10.1. Coastal and littoral dynamics

Conveners: Mouncef Sedrati, France Floc'h, Imen Turki

Predicting the impacts of global change on coastal environments remains a key research topic due to the difficulties in observing, understanding and modeling important physical processes at various spatial and temporal scales. Knowledge of coastal change and associated coastal flooding and erosion risks is of particular societal importance for countries with extensive coastlines, such as France, and these risks are expected to increase with future climate change. This session will focus on studies of the variability and dynamics of the coastal domain from a physical, geological, sedimentary and geomorphological point of view, in interaction with the biological and human environment. It will focus on high-frequency hydro-sedimentary processes in modal time as well as in extreme conditions, morphodynamics of coastal environments in response to anthropogenic and natural forcing at different spatio-temporal scales, questioning the understanding of the resilience of coastal systems.  In this session, we want to cover, as broadly as possible, work on coastal systems conducted by in-situ monitoring, studied by physical and numerical modeling and by coupling numerical and multi-sensor approaches.

Session 10.2. Sediments of the littoral and sub-littoral zones: Sources, stocks, transport and deposit morphologies.

Convener: Anne Murat, Pierre Weill, Thierry Garlan, Gwendoline Grégoire

At the land-sea interface, the coastal environment is subject to a fragile balance maintained by the interactions between hydrodynamic, biological and anthropogenic agents. The predicted climate change increases its vulnerability. Knowledge of sediment stocks, sources, transport and exchange processes between the littoral and sublittoral domains are fundamental elements for understanding the morphodynamic functioning of this environment. Expected contributions concern studies based on the evolution of soft sediments along the coasts, including analytical approaches (sedimentological, geochemical, biological markers, etc.), in-situ field measurements or numerical and analogue modelling.

Session 10.3. Extreme events and hazards in coastal and estuarine environments in a context of climate change

Conveners: Imen turki, Julien Deloffre

Coastal erosion, marine submersion, flooding, cliff recession, landslides, etc. The last few years have been particularly affected by extreme meteorological events such as storms, floods, torrential rains, atmospheric depressions. Climate change is exacerbating extreme events in terms of intensity and frequency. This is what the IPCC (Intergovernmental Panel on Climate Change) report published in August 2021 states. To better understand the link between extreme events and climate change, as well as their level of predictability, a detailed study of their multiscale evolution and their impacts on natural sedimentary systems is necessary. In this context, this session focuses on the dynamics of these natural extreme events in relation to global climate change based on their temporal evolution and the hazards, if any, generated on land-sea interface systems (estuaries and coasts) as well as continental systems. This session will cover, as broadly as possible, work carried out based on different approaches: in-situ monitoring, multi-sensors, physical and numerical modeling.

Session 10.4. Geophysical contributions to the reconstruction of coastal, littoral, estuarine and fluvial sedimentary bodies

Conveners: Bernadette Tessier, Pierre Weil, Léo Pancrazzi, Nicolas Robin, Jean-Yves Reynaud

The architecture of sedimentary bodies, from the coastal to the fluvial domain, reflects the sedimentary dynamics of the environment, according to a wide range of time scales, from elementary processes (current, swell, wind) to eustatic and tectonic controls, through seasonal and climatic variations. High resolution subsurface geophysical imagery (seismic, georadar, electrical tomography, ...) allows to reconstruct these architectures, with sufficient penetration and resolution to decipher the combination of forcings and the interlocking of associated time scales.  This session aims to present recent advances using these tools, alone or in combination with more classical approaches based on the direct study of sedimentary bodies in outcrop or by coring (dating, paleoenvironments, tracing of sources, ...) and/or on the monitoring of their dynamics (HR topographic / bathymetric surveys, ...).

Session 11. Sedimentary environments and human activities: dredged sediments, extraction of aggregates, marine renewable energy and sustainable ports

Conveners: Laure Simplet, David Menier

Maritime transport and, more broadly, human activities at sea and on land generate pollution and nuisances in the marine environment and on the coast that need to be controlled: discharges from activities in the catchment area, discharges from maritime and port activities (dredging, careening, maritime traffic, ...), accidental pollution, disturbance of habitats, etc. The objective of this session is to present different actions, such as those carried out by Cerema or Ifremer, in the framework of its missions to support the implementation of environmental public policies in port and coastal areas. Experts from the various sectors will be able to present: 1) the ecological transition of activities and actions to reduce pollution/impacts (e.g. port greening operations, environmental protection, ...); 2) the monitoring of sediment quality (port or other) or the monitoring of the effects and mitigation « ERC » measures (avoidance, reduction, compensation) of activities (extraction of aggregates, development of MRE); 3) beneficial uses of dredged sediments and the circular economy (valorisation of dredged sediments on land and at sea); and 4) European and international recommendations, changes in the regulatory framework, technical recommendations, prospects for development and inclusion of these activities in European directives...

Session 12. Collaborative and participatory science: the co-construction of knowledge.

Conveners: Agnès Baltzer, Elsa Cariou, Christophe Piscart, Alexandra Langlais

In the current context of ecological and economic transition of communities subject to new risks, establishing an exchange of knowledge between academics, the various actors of territorial management and the general public is crucia. Indeed, this transfer of knowledge must be established in both directions, in order to integrate the complexity of the stakes and hazards and thus better estimate the risk(s) and envisage relevant and acceptable solutions. Collaborative and participatory science takes on its full meaning here, because it allows not only to involve the inhabitants of the territories in a dynamic of observation and research action (participatory) but also in a pooling and transmission of their own knowledge (collaborative) to better understand, evaluate and adapt to the evolution of their environments. In parallel, these collaborations allow scientists to establish local observation networks with high data acquisition frequency, and facilitate the exchange of important related information, allowing access to a higher, more integrated level of analysis. This session is an opportunity to bring together the different collaborative science experiments that are currently being developed and to show their successes and limitations.

Session 13. Open Session 

Personnes connectées : 1