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This is a poster given remotely at the Community Surface Dynamics Modeling System online annual meeting (May 17-21, 2021). Abstract: Source-to-sink (S2S) studies seek to explicitly link the denudation of continents with the building of basin stratigraphy in an effort to infer tectonic and climatic drivers of surface change. Quantitative models for S2S systems must incorporate geomorphic processes at both source and sink, yet more effort has been devoted to developing landscape evolution models in source terranes than equivalent models for sedimentation in marine basins. In particular, most marine sedimentation models use local linear diffusion approximations for sediment transport, which have been shown to yield reasonable stratigraphy in shallow marine environments but struggle to reproduce diagnostic features of deep marine deposits. The lack of model predictive power in deep marine environments precludes the full closure of S2S sediment budgets. We present a model for marine sedimentation with two simple modifications allowing non-local sediment transport: 1) a mechanism for sediment bypass on steep topographic slopes, and 2) a parameter allowing long-distance transport over vanishingly gentle slopes. We use Bayesian inference techniques to constrain four model parameters against the stratigraphy of the Orange Basin in southern Africa. We compare modeled against observed stratigraphy over 130 Ma of margin evolution. Our best-fit simulations capture the broad structure of the observed record, and imply non-negligible roles for both non-local model elements: sediment bypass at steep slopes and long-distance runout over gentle slopes. Residual misfit between our best-fit simulations and the stratigraphic data indicate that additional components of transport dynamics—likely hemipelagic sedimentation, grain size variations, or ocean bottom currents—might be required to achieve the longest transport distances observed in the sedimentary record. Results suggest that full closure of Earth’s sediment mass balance for S2S studies requires moving beyond local diffusion approximations, even at the longest timescales. Relatively simple modifications to modeled transport dynamics can lead to better agreement between modeled and observed stratigraphy, and may enable improved inference of landscape perturbations from the stratigraphic record.

This is a presentation given at the 2022 Geological Society of America annual meeting (October 9-12, 2022). It summarizes Shobe et al. (2022; Basin Research). Abstract: Passive margin stratigraphy holds time-integrated records documenting the evolution of landscapes that are long gone. It is probably possible to read the stratigraphic record by inverting coupled landscape evolution models and stratigraphic forward models (SFMs) for past landscape boundary conditions (e.g., climatic/tectonic perturbations). One hurdle is that there is not broad agreement on the optimal form of the SFMs we use to simulate marine sediment transport and the development of the offshore stratigraphic record over geologic time; there has been a lack of tests against observed stratigraphy in well-constrained environments. Specifically, it is not clear whether SFMs should be governed primarily by local (sediment transport rate depends only on local bathymetry) or nonlocal (transport rate depends on the history of bathymetry experienced along a transport pathway) sediment transport processes. Here we develop a simple nonlocal SFM, which incorporates the long-term average effects of nonlocal processes like turbidity currents and marine debris flows, and test it against a commonly used local model to determine which approach provides the best fit to stratigraphy in a well-constrained natural experiment. We invert for optimal model form by comparing calibrated implementations of both models against seven seismic sections from the Southeast Atlantic Margin representing 130 Ma of sediment accumulation. Results suggest that observed stratigraphy is not compatible with the local SFM and that fitting observed stratigraphy requires strong contributions from slope bypass and long-distance transport processes. This outcome holds true in cases where the model is only compared to the observed modern bathymetric surface, as well as cases where all seismic reflectors are considered. Processes of sediment bypass and long-distance transport may be essential to modeling realistic passive margin stratigraphy, and incorporating such processes into our inversion models may therefore clarify source-region dynamics inferred from the sedimentary record.

This is a poster presented at the 2022 American Geophysical Union annual meeting (December 12-16). It summarizes Shobe et al. (2022; Basin Research). Abstract: One way to decipher the stratigraphic record to reveal information about surface processes is through inverse analysis using forward models. In this approach, a forward surface process model that generates stratigraphy is run many times with varying parameter values, and the output stratigraphy is compared against observations. The parameter values that generate best-fit stratigraphy may then tell us something about surface processes. Inverse analysis of forward models is often used to infer past forcings to landscapes, but it can also be used to make inferences about process dynamics. We use inverse analysis of forward models to ask: How should we model seascape evolution and the development of passive margin stratigraphy over geologic time? Understanding the evolution of passive margins is essential because they contain Earth’s longest and most complete records of landscape change on adjacent continents. Yet there is as yet no consensus about the process representations that should make up a simple but complete seascape evolution model. Should margin evolution be governed by processes where downslope sediment flux depends only on local slope? Or should nonlocal processes where sediment flux depends on factors other than local slope, such as the history of slopes experienced along a transport pathway, play a major role? We conduct a data-driven inversion exercise using seven stratigraphic sections from the Southeast Atlantic Margin to assess the importance of nonlocal transport processes to building passive margin stratigraphy. We compare two mathematical models for seascape evolution: one that is purely local and one that incorporates nonlocal transport. The two models can converge through parameter changes alone, such that data-driven inversion can determine quantitatively the optimal process representation. Producing observed stratigraphy requires significant contributions from nonlocal processes like slope bypass and long-distance sediment transport; this result is true regardless of whether only the modern bathymetry or the full stratigraphic record is used to constrain the inversion. Results suggests that nonlocal processes dominate the development of passive margin stratigraphy and are essential ingredients in models used to infer past landscape dynamics from the stratigraphic record.

International audience

National audience; Environ 70% du relief émergé terrestre est caractérisé par des surfaces érosivespossédant un faible gradient topographique, aussi appelées surfaces d’aplanissement.Certains géomorphologues défendent l’idée que ces surfaces sont des reliques d’ancienspaléoreliefs, partiellement préservés des phénomènes d’érosion durant des dizaines demillions d’années. Une telle préservation en ferait les témoins privilégiés de l’évolutiondes surfaces continentales, depuis la formation de ces surfaces jusqu’à nos jours.Certaines des plus hautes surfaces d’aplanissement d’Afrique, localisées à plus de 2000m d’altitude, sont considérées dans la littérature comme étant des reliques d’unesurface Mésozoïque, la Gondwana surface (King, 1962). En particulier, le plateau deNyika (ca 2200 a.s.l.), localisé au nord du Malawi, est l’une des plus importantesreliques potentielles de cette paléosurface. Toutefois, la possibilité de préserver desreliefs aussi anciens est un sujet débattu dans la littérature, particulièrement sous unclimat tropical.L’exploration de ce plateau a permis d’identifier un niveau de cuirasse détritique,aujourd’hui sur un haut-topographique. Cette cuirasse, composé de clastes d’unecuirasse primaire riche en hématite cimentés par une matrice goethitique, a été datégrâce à la méthodologie de datation (U-Th)/He des oxydes et hydroxydes de fer.L’analyse minéralogique et géochimique de grains en provenance des clasteshématiques révèle la complexité de ces zones, qui sont pour la plupart composées d’unmélange de générations d’oxydes de fer. La datation de cette cuirasse a toutefois permisde faire ressortir que sa matrice possède un âge Quaternaire. A contrario, certainsclastes préservés, peu impactés par les phénomènes de dissolution/recristallisation àl’origine des mélanges générationnels, possèdent des âges remontant au Dévonien.La topographie initiale du plateau n’a pas été préservée, des bancs de cuirassesdétritiques se retrouvant aujourd’hui sur des hauts topographiques. Toutefois, cesrésultats montrent que des cuirasses détritiques se sont développés sur cette surface, ousur une surface supérieure adjacente, au cours du Dévonien avant d’être érodées pourpermettre de former les cuirasses aujourd’hui en surface. Par ailleurs, cette étude tendà supporter l’idée que le cuirassement des plateaux en contexte tropical joue un rôle clédans leur préservation.

National audience; L’approche Source to Sink (S2S) vise à mettre en cohérence la dynamique des zonessource, de transfert et de sédimentation dans le temps et dans l’espace. L’approchetemporelle de la sédimentation est depuis longtemps résumée sous forme dediagramme de Wheeler permettant de mettre en évidence les périodes de dépôts et dehiatus, ainsi que les passages latéraux et l’extension du bassin.Dans une approche Source to Sink, appliquée au domaine orogénique, nous proposonsd’intégrer la dynamique de la zone source dans les diagrammes de Wheeler. Ceci estappliqué au domaine pyrénéen et à ses deux avant-pays.Le long de coupes Nord-Sud, outre les diagrammes de Wheeler classiques, sont intégrésles déplacements verticaux, la taille de la chaine au cours du temps en se basant sur lesdonnées thermochronologiques et structurales.La dynamique de transport est également reportée sur ces diagammes en intégrant lesdonnées de traçage de source et les directions de transport.La construction de ces diagrammes permet de mettre en regard les différentes étapesde la croissance du prisme orogénique avec :1) les différents stades de remplissage des bassins adjacents (foreland etretroforeland), notamment, les changements de direction de drainage ouencore le passage underfilled à overfilled.2) les deformations far field (Massif Central et Bassin de Paris) enregistrées par lesperiodes d’érosion et de hiatus.Ce travail a été financé par le projet Source-to-Sink (BRGM-TOTAL).

National audience; Les connaissances acquises sur l’exhumation de la chaine Pyrénéenne et l’évolution desbassins d’avant-pays adjacents permettent à présent d’appréhender ce systèmeorogénique complexe dans une démarche intégrative dans l’espace et le temps.Cette approche, dite « source-to-sink » s’attache à comprendre l’évolution du routagesédimentaire depuis la Source (relief orogénique, craton, recyclage de bassin) enpassant par la zone de transfert (périphériques ou internes au bassin) jusqu’au réservoirfinal (bassin flexural, bassin turbiditique profond). Nous proposons, dans le cadre decette nouvelle cartographie, de compiler les données disponibles et nouvellementacquises dans le projet, sur l’ensemble du domaine péri-pyrénéen du Golfe du Lion àl’Est jusqu’au Golfe de Gascogne à l’Ouest en incluant le Massif Armoricain au Nordjusqu’au bassin de Madrid au Sud.La réalisation de ces cartes s’appuie sur l’utilisation de nombreuses méthodes et outils,tels que les reconstructions cinématiques du système Ibérie-Europe-Méditerranée, lescoupes restaurées, l’histoire d’exhumation par thermochronologie, le traçage dessources, la caractérisation des surfaces d’altération et d’érosion, la synthèse de l’activitédes accidents structuraux majeurs, les reconstructions paléogéographiques, l’analyse desgéométries sédimentaires et des directions de transport ainsi que la quantification desvolumes préservés dans les bassins.Les pas de temps choisis pour ces cartes permettent de rendre compte de différentsstades d’évolution tectono-sédimentaire du système péri-pyrénéen au stade dequiescence de l’orogenèse (1) à 65 Ma, Danien, et aux stades précoces de l’orogenèse(2) Thanétien terminal (56Ma) et (3) Yprésien (52 Ma). Les compilations effectuéesmettent en regard domaines exhumés et zone de sédimentation en termes de flux et devolumes, et permettent de cartographier les systèmes de routage et leur évolution aucours d’un cycle de construction d’un orogène.Travaux de recherche financés et réalisés dans le cadre du programme BRGM-TOTALSource-to-Sink

International audience; Source-to-sink (S2S) studies seek to explicitly link the denudation of continents with the building of basin stratigraphy in an effort to infer tectonic and climatic drivers of surface change. Quantitative models for S2S systems must incorporate geomorphic processes at both source and sink, yet more effort has been devoted to developing landscape evolution models in source terranes than equivalent models for sedimentation in marine basins. In particular, most marine sedimentation models use local linear diffusion approximations for sediment transport, which have been shown to yield reasonable stratigraphy in shallow marine environments but struggle to reproduce diagnostic features of deep marine deposits. The lack of model predictive power in deep marine environments precludes the full closure of S2S sediment budgets.We present a model for marine sedimentation with two simple modifications allowing non-local sediment transport: 1) a mechanism for sediment bypass on steep topographic slopes, and 2) a parameter allowing long-distance transport over vanishingly gentle slopes. We use Bayesian inference techniques to constrain four model parameters against the stratigraphy of the Orange Basin in southern Africa. We compare modeled against observed stratigraphy over 130 Ma of margin evolution. Our best-fit simulations capture the broad structure of the observed record, and imply non-negligible roles for both non-local model elements: sediment bypass at steep slopes and long-distance runout over gentle slopes. Residual misfit between our best-fit simulations and the stratigraphic data indicate that additional components of transport dynamics—likely hemipelagic sedimentation, grain size variations, or ocean bottom currents—might be required to achieve the longest transport distances observed in the sedimentary record. Results suggest that full closure of Earth’s sediment mass balance for S2S studies requires moving beyond local diffusion approximations, even at the longest timescales. Relatively simple modifications to modeled transport dynamics can lead to better agreement between modeled and observed stratigraphy, and may enable improved inference of landscape perturbations from the stratigraphic record.

International audience; The southern African Plateau is a dominant feature of African topography but there is considerable debate about when and how it formed. Mantle dynamics have been suggested to play an important role in the topographic evolution, but the time and specific mechanisms of topographic development are still contested. Three main intervals have been proposed for when most of the uplift occurred in southern Africa: 1) it was already elevated at the time of Gondwana breakup at ~150 Ma due to large igneous province activity based on models of rift flank uplift, 2) uplift occurred 100-80 Ma either due to deep mantle or lithospheric processes based on a major erosion phase detected in thermochronology and marine sediment flux, or 3) uplift occurred after ~30 Ma due to small scale convection in the upper mantle based on geomorphic planation surfaces and river profile analysis. Here, we test which of the three intervals of plateau development are plausible using erosion, sedimentation, and topographic data from southern Africa and a landscape evolution model. Recent work from several efforts has provided a clearer picture of the erosion history of the plateau surface and margins using low temperature thermochronology and the geometries of the depositional systems in the surrounding offshore basins. Landscape evolution model results are directly compared with apatite fission track and (U-Th)/He dates from across the plateau, sediment flux volumes in the surrounding marine basins, and present-day topographic metrics. We use an inversion method to constrain the range in erosional and uplift model parameters that can best reproduce the observed data. Results indicate two families of uplift histories are most compatible with the data. Both have limited initial topography and some topographic uplift and continental tilting starting in the east of the continent at ~95 Ma. In one acceptable scenario nearly all of the topography, ~1500 m, is created at this time with very little uplift in the Cenozoic. In the other acceptable scenario, only ~500 m of uplift occurs in the mid-Cretaceous with another ~850 m of uplift in the mid-Cenozoic. The data cannot easily distinguish between these two uplift patterns suggesting different proxies would be helpful to fully constrain the timing of plateau development and any climatic influences on the erosion history.

International audience; The Zambezi System has been studied from its upstream catchment to the distal part of its deep-sea fan from 145Ma (Cretaceous to today), in the frame of the PAMELA project (Passive Margin Experiment Laboratory) fundedby TOTAL and IFREMER. This study was based offshore for the sink, on the sequence stratigraphic analysis of anextensive dataset of seismic lines calibrated on re-dated wells and onshore for the source, on a geomorphologicalanalysis of the stepped planation surfaces.The geological history can be summarized as follows. (1) The Lower Cretaceous is characterized by a decreaseof the sediment supply from 46 000 to 16 000 km3/Ma, at time of the margin topographic differentiation. (2) TheLate Cretaceous-Paleocene is characterized by three major uniformities intra-Cenomanian, uppermost Santonianand around the K-T boundary and is coeval with an increase of the sedimentary flux (21 000 km3/Ma) located intwo depocenters, north of the Limpopo Plain and below the modern Zambezi Delta. (3) The Eocene period is aperiod of carbonate production and of sharp decrease of the siliciclastic flux (3 000 km3/Ma). (4) The Late Eocene(up to today) is the birth of the modern Zambezi Delta characterized by a dramatic increase of the sedimentaryflux, from 13 000 km3/Ma (Oligocene) to 78 000 km3/Ma (Plio-Pleistocene) with three major unconformities atbase Early Miocene, base Late Miocene and base Pliocene.The efficiency of the sediment transport toward the deepest part of the sedimentary system - i.e. the ratio betweenthe volume of sediment in the delta and the one in the deep-sea-fan - changed trough time with three periods ofefficient transport during the Late Cretaceous, the Late Miocene and the Early Pliocene.These changes of sedimentary systems reflect the deformation of the African Plate, with (1) a major uplift of theSouth African Plateau from Late Cenomanian to Campanian times due to the migration of Africa over the SouthAfrican superplume, (2) a period with no deformation and a hot humid climate during Eocene and (3) the growthof the three modern domes from 40 Ma with an increasing rate around 10 Ma: the eastern side of the South AfricanPlateau, the East African and the Madagascar Domes

International audience; A source to sink study was performed at the scale of Africa based on (1) the measurement of the compactedsiliciclastic sediment volumes preserved in the African Basins (margins, rifts, intracratonic), for the sink (see forthe method in Guillocheau et al., 2012, Basin Research) and (2) the measurement of the eroded volumes obtainedby the difference of elevation between the modern topography and remarkable deformed planation surfaces(etchplains or pediplains), for the source (see for the method in Guillocheau et al., 2018, Gondwana Research).Two main planation surfaces of Upper Cretaceous and Middle Eocene age were mapped. They are weatheringsurfaces (etchplains) known as the African Surface(s).(1) The sink analysis shows evidences of three periods of major denudation of Africa during Early Cretaceous(145-125 Ma, Berriasian-Barremian), Late Cretaceous (94-80 Ma) and uppermost Eocene to today (40-0 Ma).They record major Africa-scale uplifts related to mantle dynamics. The Cenozoic is a period of increase of thesiliciclastic sediment volumes with a paroxysm during Plio-Pleistocene (5.5-0 Ma), here related to the dynamic ofthe Southern African superplume and not to climate changes.(2) The range of the sedimentation rates is between 5 and 80 x 103 km3/Ma, i.e. the rates of passive margin out ofdirect feeding by active mountain belts.(2) The analysis of the denudation through time shows two different spatial patterns: from 94 to 80 Ma, denudationis located all over Africa and from 40 to 0 Ma, only along the “coastal” plain of Africa (with the noticeableexception of the Congo catchment). This is interpreted as different modes of plate deformation and relief growth.(3) The source to sink budgets has been performed on the catchment of the Congo, Orange, Zambezi and EastAfrican rivers from 94-80 Ma to today. Surprisingly, they show equilibrated balances, suggesting low chemicalerosion and/or neoformation of sedimentary particles (mainly clays: kaolinites to smectites) from the solutes alongthe sediment routing system.

International audience; Palaeogeographic maps at Africa-scale were drawn with a first attempt of palaeotopographic reconstructions andquantification. This was based on (1) mapping and dating of stepped planation surfaces of pediment/pediplainand etchplain types and (2) the assumption that these stepped planation surfaces result from uplifts combinedwith climatic changes leading to periods of more intense erosion for shaping the pediments/pediplains (see formore arguments Guillocheau et al., 2018, Gondwana Research). Six time intervals were mapped (1) 59-56 Ma(Late Paleocene), (2) 48-41 Ma (Middle Eocene), (3) 34-28 (Early Oligocene), (4) 23-16 Ma (Early Miocene), (5)11-5Ma (Late Miocene) and (6) 5-3 Ma (Early Pliocene). The main outcomes are as follows.(1) Pre-existing relief were created during a major period of uplift during Upper Cretaceous times with remnantsalong the Southern African Plateau (important remnant topography), the future East African and Ethiopian Domesand the Guinean Rise.(2) Paleocene to Late Eocene (66-40Ma) was the time interval during which Africa is (i) near sea level except theremnant relief mentioned before and (ii) intensely weathered.(3) Late Eocene (40 Ma) was a major palaeogeographic reorganization with the initiation of the modern drainages.(4) Oligocene to today (40-0 Ma) was a period of Africa-scale uplifts that reach a paroxysm during uppermostMiocene-lowermost Pliocene times (around 5 Ma).The wavelength of the topographies created since 40 Ma are higher than 1000 km and sometimes longer (e.g.all North Africa). This means that their causes of uplift can only be related to mantle dynamics. Nevertheless,denudation data (e.g. thermochronology) shows that most of the denudation was located along the “coastal” plainsof Africa or on the rift flanks (with the noticeable exception of the Congo catchment).These observations suggest that the South African superplume had a significant role in the growth of thesetopographies since 40 Ma, with a propagation of the superplume toward the north and a progressive spreadingbelow the North African lithosphere during the locking of Africa Plate with Eurasia Plate. The initiation of theuplift at 40 Ma localized the erosion along the “coastal” plains, enhanced from 40 Ma to today by isostaticrebounds and modulated by plate-scale deformation and/or major climatic changes

International audience; Los mapas paleogeográficos son esenciales para entender la dinámica terrestre. Ellos proveen las condiciones de borde necesariaspara modelos paleoclimáticos y geodinámicos, procesos superficiales y de interacción de biota. En particular, la apertura y cierrede conexiones oceánicas y el crecimiento de cordilleras son importantes agentes que permiten generar cambios climáticos eintercambio de biota. Sin embargo, el periodo y extensión espacial de tales eventos son altamente controversiales y regularmentepuestos a prueba por nuevos datos. Como parte del proyecto ERC “MAGIC”, enfocado en los monzones asiáticos durante latransición Eoceno-Oligoceno, hemos producido una serie de mapas paleogeográficos durante el Cenozoico en el periodo entre60 y 20 Ma. La creación de mapas paleogeográficos siguió una metodología que integró datos paleobatimétricos, de paleocostay paleotopográficos en un modelo tectónico coherente usando el software gratuito Gplates. (1) Usamos él modelo tectónicopresentado por Seton et al. (2012), el cual fue modificado usando restauraciones de los Andes, el Arco de Scotia, África, elMediterráneo y la zona de colisión del Tibet-Himalayas. (2) La paleobatimetría fue tomada de Müller et al. (2008) la cual fuedeterminada usando la relación de edad versus profundidad y asumiendo expansión de fondo oceánica simétrica. (3) Los datosde paleocostas fueron tomados de Golonka (2006) y modificados posteriormente mediante la comparación de estos con datosde fósiles marinos y terrestres de la página www.paleobiodb.org y geológicos. (4) Para reconstruir las paleoelevaciones, una delas tareas más controversiales, utilizamos una compilación de datos de isotopos estables, fisonomía de hojas y termocronologíacombinada con y el registro geológico. Finalmente, usando el software libre GMT y un set de máscaras modificamos el relieveactual obtenido a partir de la ETOPO de acuerdo con las estimaciones obtenidas para cada región y en cada intervalo de tiempo.Nuestro enfoque pone especial énfasis en la evolución de los márgenes continentales, logrando acoplar la evolución topográficade los continentes con el cambio constante de sus márgenes. Considerando la adición constante de nuevos datos y modelos, elvalor de este método esta dado por la posibilidad de generar un modelo progresivo de paleorelieve que puede ser contrastado ymejorado con nuevos datos.

International audience; A source to sink approach was performed at the scale of a continent – Africa - in the frame of the TopoAfrica project, with three main objectives (1) the characterization of the relative importance of deformation (uplift) and climate (precipitation) (2) the quantification of the deformation, its nature and causes, (3) the effect of those deformations on the past African topography and on the sediment routing system. We mainly focused on Western, Central and Austral Africa, characterized by anorogenic relief (plains and plateaus) record of long (several 100 km) to very long (several 1000 km) wavelength deformations, respectively of lithospheric and mantle origin. The sink measurement was based on the seismic stratigraphic analysis of numerous regional seismic lines (from the upstream part of the margin to the abyssal plain) merge of industrial and academic data, calibrated in ages and lithologies on reevaluated wells to get the best possible ages. Volumes measured between successive time-lines, were compacted for a comparison with solid eroded volumes.The source study was performed using dated stepped planation surfaces (etchplains and pediplains) - key morphological features of Africa - mappable at catchments-scale. During Late Paleocene to Middle Eocene times, Africa experienced a very hot and very humid climate leading to the formation of an African-scale weathering surface (etchplain) known as the African Surface. This surface today deformed and preserved as large plains, domes or plateaus, can be used as (1) a marker of the very long wavelength deformations and (2) a reference level to measure eroded volumes since 40 Ma. Some other younger planation surfaces were also mapped of (1) Early Oligocene and (2) Late Miocene ages.(1) Deformation (uplift) is the dominant control of the sediment budget. Climate (precipitation) changes only enhance or inhibit a deformation-controlled flux.(2) The sources of clastic sediments are or closed marginal bulges or far field domes due to mantle dynamics with by-pass (transfer zones) along long-lasting polygenic surfaces located in.

International audience; The late Cretaceous to early Paleogene is a period of major deformations of the western part of the Eurasian plateknown as the Laramide deformations. These are correlated with major paleogeographic changes - widespreadupper Cretaceous marine platforms (chalk) are uplifted, intensively eroded and announced the present-dayconfiguration of the geology of north-western Europe.These deformations occur in a complex geodynamic setting within both the context of the Africa-Eurasiaconvergence and the North Atlantic opening. Two main mechanisms are proposed: (1) surface upwelling causedby flows in the underlying mantle (Iceland Plume upwelling); (2) horizontal lithospheric deformations (Africa/Eurasia convergence).The precise ages of these deformations and the type of reliefs created (height, wavelength etc.) are still poorlyknown. Here we link onshore landforms (planation surfaces and incised valleys) located on outcrops of Proterozoicto Paleozoic basement (Armorican Massif, French Massif Central) to onshore-offshore sediment accumulationareas (Aquitanian, Paris, Western Approaches, London, Belgium, North-Sea Basins). The aim is to propose atopographic reconstitution of the reliefs and basins of western Europe - for the uppermost Cretaceous to thePaleogene period - performing restored european scale cross sections (geomorphology and geology).This study is based on two different approaches:- Erosional domain - on the mapping and chronology of all the macroforms (weathering surfaces and associatedalterites, pediments and pediplains, incised rivers) dated by intersection with the few preserved sediments,weathering and the volcanics.- Depositional domain - on a more classical dataset of seismic lines and wells, coupled with biostratigraphicrevaluations (characterization and dating of vertical movements of the basins).This work is founded and carried out in the framework of the BRGM-TOTAL project Source-to-Sink.

International audience; The South African (Kalahari) Plateau is the world’s largest non-orogenic plateau. It forms a largescaletopographic anomaly (×1000 km) which rises from sea level to > 1000 m. Most mechanisms proposed toexplain its elevation gain imply mantle processes. The age of the uplift and the different steps of relief growthare still debated. On one hand, a Late Cretaceous uplift is supported both by thermochronological studies andsedimentary flux quantifications. On the other hand, geomorphological studies suggest a Late Cenozoic upliftscenario.Onshore, on the mapping and chronology of all the macroforms (weathering surfaces and associatedalterites, pediments and pediplains, incised rivers, wave-cut platforms) dated by intersection with the fewpreserved sediments and the volcanics (mainly kimberlites pipes).Offshore, on a more classical dataset of seismic lines and petroleum wells, coupled with biostratigraphicrevaluations (characterization and dating of vertical movements of the marginssediment volumemeasurement).The main result of this study is that the South African Plateau is an old Upper Cretaceous relief (90-70Ma) reactivated during Oligocene (30-15 Ma) times. Its evolution can be summarized as follows:• 100-70 Ma (Cenomanian to Campanian): low elevation plateau (0-500 m) with older and higher reliefslocated along the Indian side, acting as a main divide between the Atlantic and the Indian Oceans. First upliftoccurred in the east at ~92 Ma, with a fast flexuration of the Indian margins. This initiates a paroxysm of theerosion (90-80 Ma) with the growth of a large delta along the Atlantic margin (Orange delta). Deformationmigrated progressively westward and resulted on the growth of the Atlantic marginal bulge between 81 and70 Ma. Most of the present-day relief was probably created at this time. This is supported by the decrease ofthe sedimentary flux which suggests a reorganisation of the interior drainage pattern.• 70-30 Ma (Uppermost Cretaceous-Paleogene): most of the relief is fossilized and weathered relativetectonic quiescence.• 30-15 Ma (Oligocene-Early Miocene): second period of the South African Plateau uplift. Most of thedeformation took place along the Indian side of the Plateau (strike flexure) feeding the Zambezi, Limpopo andTugela deltas.• Since at least Middle Miocene times, all those reliefs have been fossilized, with very low erosion rates(x1m/Ma), in response to the major aridification of southern Africa.

International audience; A source to sink approach was performed at the scale of a continent – African the frame of theTopoAfrica project, with three main objectives (1) the characterization of the relative importance ofdeformation (uplift) and climate (precipitation) (2) the quantification of the deformation, its nature and causes,(3) the effect of those deformations on the past African topography and on the sediment routing system. Wemainly focused on Western, Central and Austral Africa, characterized by anorogenic relief (plains andplateaus) record of long (several 100 km) to very long (several 1000 km) wavelength deformations,respectively of lithospheric and mantle origin.The sink measurement was based on the seismic stratigraphic analysis of numerous regional seismiclines (from the upstream part of the margin to the abyssal plain) merge of industrial and academic data,calibrated in ages and lithologies on reevaluated wells to get the best possible ages. Volumes measuredbetween successive time-lines, were compacted for a comparison with solid eroded volumes. Uncertaintieswere calculated (including ages, time-depth conversion law, porosities...) using the Volume Estimatorsoftware.The source study was performed using dated stepped planation surfaces (etchplains and pediplains) keymorphological features of Africa mappable at catchments-scale. During Late Paleocene to Middle Eocenetimes, Africa experienced a very hot and very humid climate leading to the formation of an African-scaleweathering surface (etchplain) known as the African Surface. This surface today deformed and preserved aslarge plains, domes or plateaus, can be used as (1) a marker of the very long wavelength deformations and (2)a reference level to measure eroded volumes since 40 Ma. Some other younger planation surfaces were alsomapped of (1) Early Oligocene and (2) Late Miocene ages.(1) Deformation (uplift) is the dominant control of the sediment budget. Climate (precipitation) changesonly enhance or inhibit a deformation-controlled flux.(2) The sources of clastic sediments are or closed marginal bulges or far field domes due to mantledynamics with by-pass (transfer zones) along long-lasting polygenic surfaces located in between.(3) Africa-scale deformations occurred during Late Cretaceous (Turonian-Coniacian) and around theEocene-Oligocene boundary with a break contemporaneous of intense chemical erosion from 75 Ma andmainly from 65 to 40 Ma. Most of the African relief and topography are younger than 40 Ma. Late Cretaceousrelief are only preserved in the Guinea Rise and the Southern African Plateau.

International audience; Paleogeographic maps are essential for understanding Earth dynamics. They provide the necessary boundaryconditions for climate and geodynamic modeling, surface processes and biotic interactions. In particular, theopening and closing of ocean gateways and the growth of major mountain belts are major drivers of climatechanges and biotic interchange. However, the timing and spatial extent of such events are highly controversial andregularly questioned by new data. As part of the ERC “MAGIC” project focusing on Asian Monsoons during theIcehouse to Greenhouse transition we thus produced a set of worldwide Cenozoic paleogeographic maps in theperiod time between 60 to 20 Ma, with a set of boundary conditions specific to the India-Asia collision zone andthe Drake Passage.The creation of a paleogeographic map followed a rigorous and reproductively methodology that integrates paleo-bathymetric, paleoshoreline and paleotopographic data into a coherent plate tectonic model using the open sourcesoftware GPlates. (1) We use the model provided by Seton et al. (2012) as a first order tectonic model modifiedto integrate the full restoration of five regions: the Andes, the Scotia Arc, Africa, The Mediterranean Sea and theTibet-Himalayan collision zone. (2) The paleobathymetry was provided by Müller et al. (2008) using age-depthrelationships and assuming symmetric ridge spreading. (3) Paleoshoreline maps were modified according to thefossil database from fossilworks.org and the geological record and were used to represent the boundary betweenterrestrial and marine paleo-environments. (4) To reconstruct paleoelevations, the most controversial task, wecompiled a wide range of data including stable isotope, leaf physiognomy, and thermochronology combined withregional fossil and geological records (tectonic setting) and geomorphological data. Finally, we use the opensource GMT software and a set of masks to modify the current Earth relief model (ETOPO) according to theestimated paleoelevation for specific region at each period of time.Our approach specifically takes into account the evolution of continental margins. Paleotopographic evolution iscoupled with the evolving shape of continents. Considering the constant addition of new data and models, thevalue of this method is to generate a progressive paleorelief model of the Earth that can be easily compared andupdated with new data.

International audience; The post-rift siliciclastic sediment budget of passive margins is a function of (1) the deformation (uplift) of theupstream catchment, of (2) the climate (precipitation) regime and of (3) the oceanic circulation (mainly sinceMiocene times). The main questions in source to sink studies are (1) to quantify the relative importance of theerosion due to uplifts or to precipitation changes and (2) to characterize the source of the sediments.A source to sink study was carried out in Western, Central and Austral Africa, characterized by anorogenic relief(plains and plateaus) that record long (several 100 km) to very long (several 1000 km) wavelength deformationsrespectively of lithospheric and mantle origin.The sink measurement was based on seismic lines and wells (industrial – IODP) using the VolumeEstimatorsoftware including the calculation of the uncertainties (Guillocheau et al., 2013, Basin Research). The source studywas performed using dated stepped planation surfaces (etchplains and pediplains), mappable at catchments-scale(Guillocheau et al., in press, Gondwana Research).Results: (1) Deformation (uplift) is the dominant control of the sediment budget. Climate (precipitation) changesonly enhance or inhibit a deformation-controlled flux. (2) The sources of siliciclastic sediments are either closedmarginal bulges or far field domes due to mantle dynamics with river by-passing over long-lasting polygenicsurfaces located between the bulges and domes.Two main periods of African-scale deformations (contemporaneous with an increase of the sedimentary flux)are confirmed, one during Late Cretaceous (Turonian-Coniacian) and the second around the Eocene-Oligoceneboundary with a gap and intense chemical erosion from 75 Ma and mainly from 65 to 40 Ma.