Here we report on Neanderthal engravings on a cave wall at La Roche-Cotard (LRC) in central France, made more than 57±3 thousand years ago. Following human occupation, the cave was completely sealed by cold-period sediments, which prevented access until its discovery in the 19th century and first excavation in the early 20th century. The timing of the closure of the cave is based on 50 optically stimulated luminescence ages derived from sediment collected inside and from around the cave. The anthropogenic origin of the spatially-structured, non-figurative marks found within the cave is confirmed using taphonomic, traceological and experimental evidence. Cave closure occurred significantly before the regional arrival of H. sapiens, and all artefacts from within the cave are typical Mousterian lithics; in Western Europe these are uniquely attributed to H. neanderthalensis. We conclude that the LRC engravings are unambiguous examples of Neanderthal abstract design.

Le site de Bergeresse a Abilly se trouve en rive droite de la Creuse, sur le versant est de la vallee, a quelques centaines de metres en contrebas des formations d’alteration du Turonien superieur, livrant les dalles de silex exploitees au Neolithique final pour la fabrication des grandes lames sur livres de beurre. La fouille d’ateliers de debitage du silex a porte sur une surface de plus de 9 000 m2, dont 1 400 m2 ont ete fouilles manuellement au cours de 7 campagnes de fouille programmee d...

La Reserve Naturelle Regionale Geologique (RNRG) de Pontlevoy inauguree en 2018 comprend deux anciennes carrieres (carriere du Four a Chaux et carriere du Haut de la Plaine Saint-Gilles). On peut y observer en superposition stratigraphique les principales formations miocenes du secteur situe entre Loire et Cher au sud de Blois : Calcaire de Beauce de l’Aquitanien, Sables et marnes du Blesois du Burdigalien et Faluns du Blesois du Langhien, les deux dernieres etant fossiliferes. Apres une breve synthese sur les formations miocenes de la region, sont presentees ici des donnees sedimentologiques sur les formations visibles dans la RNRG et les resultats de nouvelles fouilles paleontologiques dans les Sables et marnes du Blesois de la reserve. La prospection geophysique par conductivite electrique, ainsi que les sondages et forages carottes effectues entre les deux carrieres avant l’amenagement de la reserve, ont revele (1) la presence d’une nouvelle formation fluviatile comblant un profond chenal incise dans le falun langhien ; cette formation peut etre rapportee au Serravallien ou au Miocene superieur et (2) la presence d’une faille a regard est et decrochement senestre affectant l’ensemble des formations miocenes.

The prehistoric site of La Roche-Cotard (LRC) is located on the right bank slope of the Loire Valley, a little upstream of Langeais in Indre-et-Loire. The site was made accessible by extensive material collection in 1846. The main cave, LRC I, was excavated in 1912: it contained a middle Paleolithic industry and digital traces were discovered in 1975 and validated in 2008. The resumption of excavations on the site since 2008 has highlighted a powerful 11 meter section with 22 distinct layers, the lower part of which fills a shelter : locus LRC IV, very close to LRC I. The stratigraphy combines from the bottom to the top, karstic inputs, fluvial and eolian sands from the Loire valley and slope deposits. Indices of anthropic occupation (lithic industry, burned bones) attest to the occupation of this space. Numerous radiocarbon and OSL ages make it possible to chronologically constrains this filling between the limit of the isotopic stages 7 and 6 (layer 22 - 169 ka) and the end of stage 3 (layer 2 - 25 ka). The locus has given rise to a multidisciplinary study as complete as possible (sedimentology and micromorphology, small and large vertebrate faunas, lithic industry ...). These data provide new information on the palaeoenvironmental evolution of the region, which is poorly known in this time range. The geometry and the age of the deposits lead to the hypothesis that the main cave LRC I was impenetrable by Homo sapiens at least starting from the beginning of the isotopic stage 3 (60 ka) and thus that the parietal productions with symbolic character of the cave are most likely to be attributed to Neanderthal man.

Le site préhistorique de La Roche-Cotard (LRC) se trouve sur le versant de rive droite de la vallée de la Loire, un peu en amont de Langeais, en Indre-et-Loire. Le site a été rendu accessible grâce à un important prélèvement de matériaux en 1846. La grotte principale (LRC I) a été fouillée en 1912 : elle contenait une industrie du Paléolithique moyen et des tracés digitaux y ont été découverts en 1975 et validés en 2008. La reprise des fouilles sur le site à partir de 2008 (locus LRC IV très proche de LRC I) a permis de mettre en évidence une coupe puissante de 11 mètres comprenant 22 couches distinctes dont la partie inférieure comble un abri. La stratigraphie combine, de bas en haut, des apports karstiques de milieu souterrain, des sables fluviatiles et éoliens issus de la vallée de la Loire et gravitaires du versant. Des indices d'occupation anthropique (industrie lithique, os brûlés) attestent une occupation de cet espace. Les nombreuses datations des couches par radiocarbone et par OSL permettent de situer chronologiquement ce remplissage entre la limite des stades isotopiques marins 7 et 6 (couche 22 ‑ 169 ka) et la limite des stades 3 et 2 (couche 2 - 25 ka). Le locus a donné lieu à une étude pluridisciplinaire aussi complète que possible (sédimentologie et micromorphologie, faunes de petits et grands vertébrés, industrie lithique). Ces données apportent des précisions nouvelles sur l'évolution paléoenvironnementale de la région, mal connue dans cette fourchette de temps. La géométrie et l'âge des dépôts conduisent à l'hypothèse selon laquelle la grotte (LRC I) a été impénétrable par Homo sapiens au moins à partir du début du stade isotopique marin 3 (60 ka) et donc que les productions pariétales à caractère symbolique de la grotte sont très probablement à attribuer à l'homme de Néandertal.

In Europe and North America the prevailing model of "natural" lowland streams is incised-meandering channels with silt-clay floodplains, and this is the typical template for stream restoration. Using both published and new unpublished geological and historical data from Europe we critically review this model, show how it is inappropriate for the European context, and examine the implications for carbon sequestration and Riverine Ecosystem Services (RES) including river rewilding. This paper brings together for the first time, all the pertinent strands of evidence we now have on the long-term trajectories of floodplain system from sediment-based dating to sedaDNA. Floodplain chronostratigraphy shows that early Holocene streams were predominantly multi-channel (anabranching) systems, often choked with vegetation and relatively rarely single-channel actively meandering systems. Floodplains were either non-existent or limited to adjacent organic-filled palaeochannels, spring/valley mires and flushes. This applied to many, if not most, small to medium rivers but also major sections of the larger rivers such as the Thames, Seine, Rhone, Lower Rhine, Vistula and Danube. As shown by radiocarbon and optically stimulated luminescence (OSL) dating during the mid-late Holocene c. 4-2 ka BP, overbank silt-clay deposition transformed European floodplains, covering former wetlands and silting-up secondary channels. This was followed by direct intervention in the Medieval period incorporating weir and mill based systems- part of a deep engagement with rivers and floodplains which is even reflected in river and floodplain settlement place names. The final transformation was the "industrialisation of channels" through hard-engineering - part of the Anthropocene great acceleration. The primary causative factor in transforming pristine floodplains was accelerated soil erosion caused by deforestation and arable fanning, but with effective sediment delivery also reflecting climatic fluctuations. Later floodplain modifications built on these transformed floodplain topographies. So, unlike North America where channel-floodplain transformation was rapid, the transformation of European streams occurred over a much longer time-period with considerable spatial diversity regarding timing and kind of modification. This has had implications for the evolution of RES including reduced carbon sequestration over the past millennia. Due to the multi-faceted combination of catchment controls, ecological change and cultural legacy, it is impractical, if not impossible, to identify an originally natural condition and thus restore European rivers to their pre-transformation state (naturalisation). Nevertheless, attempts to restore to historical (pre-industrial) states allowing for natural floodplain processes can have both ecological and carbon offset benefits, as well as additional abiotic benefits such as flood attenuation and water quality improvements. This includes rewilding using beaver reintroduction which has overall positive benefits on river corridor ecology. New developments, particularly biomolecular methods offer the potential of unifying modern ecological monitoring with the reconstruction of past ecosystems and their trajectories. The sustainable restoration of rivers and floodplains designed to maximise desirable RES and natural capital must be predicated on the awareness that Anthropocene rivers are still largely imprisoned in the banks of their history and this requires acceptance of an increased complexity for the achievement and maintenance of desirable restoration goals.

The aim of this paper is to propose an initial estimation of the annual organic matter yield induced by chemical weathering of carbonates and shales, considering their global surface at outcrop and their organic matter content. The calculation also uses data on river fluxes resulting from carbonate rocks and shales weathering in major world watersheds, published by numerous authors. The results obtained from the studied watersheds have then been extrapolated to a global scale. Despite rather large uncertainty to such an approach, the calculated value of ca. 0.1 Gt implies that the annual organic carbon yield related to carbonates and shales chemical weathering might be a non-negligible component of the global carbon cycle. The individual contributions of different watersheds necessarily depend on the organic matter content of altered rocks. They are also obviously controlled by climatic parameters. The calculated yields do not constitute a direct supply to soils and rivers because of mineralisation when organic carbon is brought in contact with the atmosphere. Even so, the release of fossil organic matter would have implications for the global carbon cycle through the efficiency of the global chemical weathering as a carbon sink. Whatever the chosen hypothesis, the results of this study suggest that the recycled organic yield is a neglected component in the global organic carbon cycle assessment. Because it exists and, in addition, because it might represent a non-negligible carbon pool, fossil organic carbon deserves to be taken into account for a better evaluation of the organic stocks in soils and rivers presently only based on climatic data and current vegetal production.

Accumulation of organic matter in fens of fluvial valleys is often related to a low terrigenous matter delivery and to palaeoenvironmental conditions inducing low mechanical erosion. These assumptions come from the interpretation of contents in organic (MO) and mineral (MM) matters in sediments, expressed in percents, and then exactly anticorrelated. Calculation of mass accumulation rates of MO ( T aMO ) and MM ( T aMM ), expressed in g m − 2 yr − 1 , shows that T aMO and T aMM generally are not anticorrelated and that high values of T aMO and T aMM could appear simultaneously.

This paper investigates how the spatial correlations between topographic attributes and a soil thickness can be improved by focusing on the relationships between them at specific spatial scales. In addition, this paper examines the effects of the topographic attribute data sources that are used as explanatory variables for modeling the response variable, and considers the possibility of model extrapolation for mapping beyond the area where the model was established. Here, factorial kriging analysis (FKA) and partial least square regression (PLSR) analysis are used to separate nuggets and small- and large-scale structures in data including four topographic attributes and soil thickness (ST). These analyses were conducted at different scales to analyze the relationships between ST and the selected topographic attributes in the southwest region of the Parisian Basin. The structural correlation coefficients from the FKA show strong correlations between the variables. These correlations, which change as a function of spatial scale, are not revealed by the linear correlation coefficients. The Eigen vectors from the principal component analysis that was performed on the small-scale and large-scale structures of the linear co-regionalization model are used to obtain ST and the topographic attributes at both spatial scales over the study area. The ST models are built as a function of topographic attributes using PLSR. Results have shown that the models built using variables that were assessed at a specific scale are better at predicting the target variable than models that were built using raw data. Regarding the models that were built using raw data, the structural correlations that occur at different spatial scales are merged together and the variance–covariance matrix of the nugget that represents data noise is not filtered out. Measures of model performance that are based on a validation data set have shown that the model based on small-scale structure (Model-S) is better for predicting soil thickness than the model based on large-scale structure (Model-L). The effects of topographic attribute data sources as explanatory variables for modeling ST are less significant than the effects of the two models for mapping. Moreover, extrapolation of the model-S beyond the area where it was generated is appropriate. The decomposition process is associated with a modeling approach, such as the PLSR, which accounts for the collinearity between predictor variables and leads to an efficient prediction model. These results are important for modeling soil properties based on topographic attributes and for spatially generalizing models that have been established over small to large areas. Thus, in the presence of nested variogram models, the correlations between variables of interest and auxiliary information should be improved by filtering out some of the spatial structures by factorial kriging. The information filtered is associated with an appropriate approach for modeling when collinearity occurs between the predictor variables and provides a suitable model for predicting and spatially generalizing a locally established model.

This work aimed to evaluate whether different types of landscape structures (undulations, lynchets and undisturbed surfaces) can be discriminated by their morphometric attributes and the soil thickness. Three models based on the factorial discriminant analysis (FDA), the multinomial logistic regression (MLR) and the classification and regression trees (CART), respectively, were developed to classify different types of landscape structures. All these statistical techniques were performed using a training sample of 586 individuals over a 17ha area located in the south-western Parisian Basin. The models developed by the CART and FDA revealed that in addition to soil thickness, the morphometric attributes slope and profile curvature significantly influence the spatial distribution of landscape structures. In addition to the variables selected by CART and FDA models, MLR model included elevation. An external validation of the classification models based on a validation sample of 148 individuals, revealed an overall well classification by CART model of 85% while those achieved with MLR and FDA models were 72% and 77%, respectively. As the predictor variables are known at all the nodes of a regular grid covering the study area; the three models developed were then used to map the landscape structures all over the 17ha area. Resulting maps revealed a total disagreement between the three models for only 3% of the study area. For more than 50% of the study area the three models predicted a similar landscape structure. For the remaining surface, at least two of the three models predicted a similar landscape structure.

Urban zones on alluvial plains offer considerable geoarchaeological potential for understanding river dynamics over large time spans and their relationship with land use, because of the extensive subsoil data that is available. In the alluvial plain of Tours, lying between the Loire and the Cher, multidisciplinary studies of the relationships between societies and environment have been conducted as part of an archaeological research programme launched in the 1960s. A sedimentary database containing data for 1309 surveys has been compiled and assembled in a geographic information system to produce geostatistical models of valley bottom geomorphology. The stratigraphy and chronology of alluvial filling have also been studied with information and C14 and OSL dating obtained during archaeological operations. Taken together, the results offer a new interpretation of the morphological evolution of the alluvial plain of Tours from the Weichselian to the present day, by providing new information that either validates or invalidates previous hypotheses: bedrock incision prior to the end of the Weichselian Upper Pleniglacial, coarse sedimentation during the Lateglacial, relative morphological stability up to the late Holocene. The morphological context of the first human settlements, which are not concentrated on the low alluvial reliefs, and the role of urbanization conditions on the present morphology of the valley floor are also presented. This applied study shows the relevance of combining different methodological approaches.

Soil erosion plays an important role in sediment and carbon storage within, and exports from, catchments. In cultivated landscapes, field borders can improve the temporary storage of eroded soil particles and associated carbon, by impeding lateral soil fluxes. These local soil accumulations can lead to the development of linear landforms (such as headlands and lynchets) which will keep evolving after field border removal. A recent study performed in a representative cultivated hillslope of the SW Parisian Basin showed that 39% of the area corresponds to landforms resulting from soil accumulation induced by former and present field borders. This study demonstrated that field borders influence greatly the landscape morphology, but also the spatial distribution of soil thickness, and locally the A-horizon thickness, which are essential parameters for the prediction of SOC stocks. This study aims at characterizing and quantifying the effect of field borders and their removal on medium term topsoil erosion and deposition rates in a cultivated hillslope of the SW Parisian Basin, consolidated in 1967. Here, we used the Cs-137 technique to assess recent patterns of soil redistribution. We measured the Cs-137 inventories of 68 soil cores sampled along transects covering the area and, more specifically, linear landforms identified along present and past field borders (i.e. lynchet and undulation landforms, respectively). Then, we used a spatially-distributed Cs-137 conversion model that simulates and discriminates soil redistribution induced by water and tillage erosion processes over the last fifty years. Finally, observations and model outputs were confronted. Our results show that tillage erosion dominate the soil redistribution in the study area for the 1954-2009 period and generated about 95% (i.e. 4.50 Mg.ha􀀀1.yr􀀀1) of the total gross erosion. Soil redistribution was largely affected by the presence of current and former field borders, where hotspots areas of deposition and erosion (>20 Mg.ha􀀀1.yr􀀀1), respectively, were observed. Land consolidation contributed to the local acceleration of topsoil erosion through the conversion of storing areas into sediment generating areas. Though the general patterns of Cs-137 inventories in the area were correctly reproduced by the model, this latter performed weakly with a r2 of 0.20. Important discrepancies were associated with sampling points located along current field borders where data suggests that tillage erosion processes cannot be described as elsewhere, i.e. as a diffusive process. These specific processes implied here should be characterised and implemented into erosion models for simulating rates and patterns of topsoil redistribution in fragmented cultivated landscapes. In addition, the use of a DEM of the present-day morphology leads to the underestimation of soil erosion and storing within linear landforms which morphology seems to have greatly evolved since 1967. This study highlights the importance of present and former field borders on the patterns and intensities of topsoil erosion and deposition processes at landscape scale. This is of particular interest concerning the improvement of our knowledge on soil organic carbon patterns and on estimation of SOC stocks.

Urban areas located in floodplains offer a great geo-archaeological potential for the comprehension of fluvial dynamics on long term and its relationship with land occupation, as they allow exploiting many survey data of the basement. In the floodplain of Tours, shared by the River Loire and Cher river, relations between human societies and environment are the subject of an interdisciplinary work within the frame of an archaeological program initiated in the late 1960's. A sedimentary database including 1309 surveys has been created then exploited in a geographic information system to produce geomorphological and geostatical models. The stratigraphy and chronology of the alluvial filling were also studied with surveys and 14C and OSL dating obtained in the course of archaeological prospections. The combined results provide a new reading of the morphological evolution of the floodplain of Tours from the Weichselian to nowadays.

Dating sedimentary series spanning the past few tens of thousands of years is often problematic due to the quality of radiocarbon data obtained from organic matter (OM), including bulk OM. This problem recently arose when establishing the chronology of a sediment infill at the Sarliève paleolake (French Massif Central). In the studied section of the cores that covers the Neolithic, Ruppia seeds yielded consistent ages for the lower part (7195 ± 75 to 6050 ± 60 yr BP). A reservoir age of 82 ± 42 14C yr was estimated through the comparison of ages derived from charcoal, Ruppia seeds, and charophyte oogonia sampled on a single level. The upper part of the cores lacks macrofossils and bulk OM dating yields unusable data because of a significant contribution of aged OM derived from the Oligocene substratum in the catchment. We therefore performed dating of lipids extracted from the sediments. The age of the lipids was 2880 ± 30 yr BP near the top of the section, i.e. much younger than the age estimated from previous correlations based on pollen assemblages. These new data call into question previous paleoenvironmental interpretations. The combined dating methodology used for the Neolithic series of Sarliève is a rather uncommon approach that may help to refine chronologies of Holocene sedimentary series.

Cet ouvrage presente les differents cycles et les composantes interactives qui se deroulent a la surface des terres emergees : l'atmosphere et l'hydrosphere vehiculant matiere et energie, la lithosphere soumise a l'erosion et la biosphere source de transformation et de diffusion. L'ouvrage dans cette nouvelle edition aborde les etapes a l'origine de l'elaboration de matiere puis toute la chaine de transport de ces materiaux depuis les zones d'erosion aux grands domaines de sedimentation oceanique. Dans cette nouvelle edition, entierement actualisee, les impacts que l'Homme introduit dans ce cycle sont particulierement etudies.