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International audience; A new Middle Pleistocene loess-palaeosol sequence was uncovered during a preventive excavation at Étricourt-Manancourt (Somme, France). The full 12-m-thick sequence exhibits five stacked glacial-interglacial cycles and integrates five in situ Palaeolithic levels and remarkably one Acheulean level dated by TL on burned flints at about 280 - 300 ka. Detailed field stratigraphic approach has been completed by a high-resolution sedimentological study (grain size, TOC) based on a set of more than 380 5-cm-thick samples collected from continuous sampling columns covering the entire units, more than 110 micromorphological block samples for thin sections analysis and a set of 37 sub-samples for the study of heavy minerals. Despite specific samples (tubes) having been extracted for future OSL dating, the geochronological control is mainly based on TL dating of heated (archaeological) flints, completed by IRSL dating on K-feldspars. The study of four reference profiles distributed throughout the excavation, and their correlation using well defined pedological level marks led to the definition of a ca. 12-m-thick cumulative loess-palaeosols succession including eighteen main stratigraphic units. This approach allowed building a global pedosedimentary sequences for the Étricourt site that presently serves as a reference for northern France, and more broadly the loess belt.The archaeological excavation, located on the slope of a dry valley, was opened over more than 4500 m². Five in situ Palaeolithic occupations have been excavated, dating from 330 to 70 ka. The youngest occupation dates from 70 to 80 ka (Weichselian) and corresponds to a recent phase of the Middle Palaeolithic. The next two layers belong to the Early Middle Palaeolithic, between 190 and 240 ka (Saalian). Finally, the two oldest layers have dates between 330 and 280 ka (Saalian) and belong to the Lower Palaeolithic. We propose to present the archaeological and chronostratigraphic results of the excavation of Etricourt-Manancourt and its input with high resolution data to the knowledge of the Saalian and the Weichselian in Northern France and in North-Western Europe.

International audience; In this study, we describe a new Middle Pleistocene loess-palaeosol sequence uncovered during a preventive excavation at Étricourt-Manancourt (Somme, France; fig. 1). The full 12-m-thick sequence exhibits five stacked glacial-interglacial cycles and integrates five in situ Palaeolithic levels and remarkably one Acheulean level dated by TL on burned flints at about 280 - 300 ka.Detailed field stratigraphic approach has been completed by (1) a high-resolution sedimentological study (grain size, TOC) based on a set of more than 380 5-cm-thick samples collected from continuous sampling columns covering the entire units, (2) more than 110 micromorphological block samples for thin sections analysis (fig. 3) and (3) a set of 37 sub-samples for the study of heavy minerals. Despite specific samples (tubes) having been extracted for future OSL dating, the geochronological control is mainly based on TL dating of heated (archaeological) flints, completed by IRSL dating on K-feldspars.The archaeological excavation, located on the slope of a dry valley, was opened over more than 4500 m² and led to the discovery of two deep sinkholes developed in the chalk bedrock (fig. 6). The bottom of the deepest one is located at more than 11 m from the surface of the topsoil and 5 m below the average chalk surface. The study of four reference profiles distributed throughout the excavation (figs. 6-9), and their correlation using well defined pedological level marks led to the definition of a ca. 12-m-thick cumulative loess-palaeosols succession including eighteen main stratigraphic units. This approach allowed building a global pedosedimentary sequences for the Étricourt site that presently serves as a reference for northern France (fig. 14 & tab. 2).Here we focus mainly on the detailed description and analysis of palaeosols. The Étricourt sequence includes five luvisols attributed to full interglacial conditions and allocated to MIS 11 (unit 17), MIS 9 (unit 14), MIS 7 (units 8b and 8a) and MIS 5 (unit 5). Two luvisols are thus identified for MIS 7. The pedosedimentary records corresponding to MIS 9 and MIS 5 are represented by well-developed pedocomplexes corresponding to the superimposition of a truncated luvisol and a humic soil complex that includes systematically a grey forest soil (greyzem).During MIS 9e, a luvisol developed on loessic deposits. The truncation of this Bt horizon (unit 14), and its degradation by hydromorphy and solifluction, indicate a phase of climatic degradation following the interglacial optimum, which could be correlated with sub-stage 9d. The “Lower Humic Soil Complex” begins then with a thick layer of dark clayey silts including scattered flint gravels (unit 13). It is characterised by a strong increase in TOC concentrations, compared to the underlying Bt horizon and by an important biological activity attested by numerous earthworm chambers, partially filled with clayey pellets. Two types of clay coatings are superimposed in this soil unit: 1) light brown to orange clay coatings and 2) brownish red to blackish micro-laminated clay coatings, typical of grey forest soils (greyzems). This soil type today is associated with forest-steppe environments and continental cool climates. The overlying horizon (unit 12), in which the Acheulean level HUD is preserved, is represented by a compacted grey-brownish loam showing a strong banded fabric of cryogenic origin. However, the lithic artefacts are very well preserved and not gelifracted.This Acheulean level has been dated around 288 ± 21 ka using TL on heated flint. The overlying dark-brown horizon (unit 11) is then characterised by a strong biological activity attested by pluricentimetric burrows and a peak in TOC values (0.20 %) indicating a typical humic steppe soil (Ah) horizon, probably of the chernozem type. According to palaeo-pedological data the Étricourt “Lower Humic Soil Complex” thus exhibits a progressive mutation of the environments from continental forest to forested steppe or steppe associated to a progressive climatic degradation directly following an interglacial (Early Glacial phase). According to both the location of the soil complex within the full sequence and TL dating results, this phase is allocated to the transition between MIS 9 and MIS 8.Within the “Lower Humic Soil Complex” occurs an intense frost episode responsible for the banding of unit 12. Since the lithic artefacts from HUD are not gelifracted, this episode of freezing-thawing must have occurred after the burial of the Palaeolithic artefacts. The following sequence of events may thus be proposed (fig. 17): erosion and degradation of the interglacial Bt horizon (unit 14) at the end of MIS 9e and 9d; formation of unit 13 during MIS 9c (HUZ occupation); erosion of unit 13 during MIS 9d; and formation of steppe soils (units 12 to 10b) during MIS 9a, according to the LR04 stack (Lisiecki & Raymo, 2005), or MIS8 according to Railsback et al. (2015); degradation and intense freeze-thaw episode responsible for the cryoturbation of unit 12 and transition to gleys and loess at the transition between MIS 9a and 8.The following glacial period that can be allocated to MIS 8 is recorded by the deposition of a non-calcareous loess (unit 8c). The overlying luvisol (unit 8b) shows mainly layered grainy clay coatings including alternations of limpid orange clays and layers of quartz grains similar to the surrounding sediment. The subsequent erosion (truncation) of this interglacial Bt horizon is underlined by a flint gravel bed (Cx). The overlying horizon (unit 8a) shows many pedorelics, papules and large soil aggregates resulting from the erosion and the reworking of the underlying Bt (unit 8b). A new illuviation phase then takes place in the channels and inter-aggregate spaces indicating the formation of a luvisol on the colluvium produced by the erosion of the underlying Bt. It is proposed that the first luvisol (unit 8b) correlates with the first peak of the curve LR04 corresponding to a temperate phase of MIS 7, 7e at ca. 240 ka, and the second luvisol (unit 8a) with the two near peaks 7c and 7a (fig. 17).The subsequent erosion of the Saalian luvisol soil complex results in the deposition of a new colluvial unit (unit 7b). The overlying greyish horizon (unit 7a), including a Middle Palaeolithic archaeological level, appears in the same stratigraphic position than the humic soil layers described in regional sequences as Mautort or Gentelles, at the transition between MIS 7 and MIS 6. At Étricourt, the Upper Saalian (MIS 6) is represented by clayey loess (unit 6b), and “limons à doublets” (wavy banded fabric, unit 6a), separated by a strong erosion phase indicated by a bed of gelifracted flints. This gravel bed contains reworked lithic industry, among which a flint likely originating from the underlying Middle Palaeolithic level included in the second MIS 7 luvisol has been dated to 222 ± 20 ka. Finally at the top of the Saalian loess unit (MIS 6) occurs a typical luvisol showing a well-marked Bt argillic horizon (unit 5) allocated to the Last Interglacial optimum (MIS 5e). The overlying Upper Humic Soil Complex exhibits the same pedostratigraphic succession than the Weichselian Early Glacial reference sequence of Saint-Sauflieu (grey forest soils with numerous earthworm chambers and several steppe soils).MIS 8 and MIS 6 loess deposits have been dated using the IRSL dating technique applied to both single and multiple aliquots (IRSLSAR and IRSLMAAD, fig. 15). The MIS 6 loess deposit has been dated to 144-180 ka, in good agreement with its chronostratigraphic attribution. By contrast, the MIS 8 loess deposit yielded an apparent MIS 7 IRSL age (215-251 ka). These underestimated IRSL ages together with the large scatter of the IRSLSAR ages, suggest that the MIS 8 loess has been reworked at the beginning of MIS 7.Using litho-pedostratigraphy and the available geochronological data (TL and IRSL dating), some correlations can be proposed between the Étricourt loess-palaeosols sequence and other sequences from NW Europe (figs. 1 & 20). This approach shows that the “Lower Humic Soil Complex”, corresponding to MIS 9 is definitely better expressed at Étricourt than in other sections of northern France and can be proposed as a new reference for this interglacial. In addition, in the section of Saint-Pierre-lès-Elbeuf in Normandy, the micromorphological study also highlights the development of a grey forest soil during MIS 9/8 transition. MIS 9 would also be represented by the Achenheim III pedocomplex in the Rhine Valley, composed of a non-leached reddish brown soil and one or more humic soil horizons. Further east in Europe, no luvisols are to be observed for MIS 7 in Achenheim and Paudorf sections, likely due to more continental climatic conditions as recorded by the development of chernozem-like soils.Finally, the mineralogical study and especially the green amphibole content allows highlighting similarities between the Étricourt sequence and loess deposits from Belgium (fig. 16). These similarities combined with the available results from other loess sequences from northern France suggest that the five green amphibole groups recently defined in Belgium can be extended to the two regions. In this context, one specific contribution of the mineralogical study in Étricourt is to suggest the existence of a hiatus within MIS 6. Beyond the chronostratigraphic interest of the distribution of green amphiboles, it will be necessary in the future to discuss its implications in terms of sources and paleogeography. Indeed, the Étricourt-Manancourt sequence covers the full Saalian complex, a period that is characterised both by major palaeogeographic changes, including the opening of the Strait of Dover and the transition from the Lower to the Middle Palaeolithic.; Cet article se focalise essentiellement sur l’approche paléopédologique d’une nouvelle séquence loessique du Pléistocène moyen découverte à l’occasion d’une fouille archéologique préventive à Étricourt-Manancourt (Somme). Cette séquence, d’une douzaine de mètres cumulés, correspond à cinq cycles glaciaire-interglaciaire et intègre cinq niveaux paléolithiques en place. Elle a fait l’objet d’analyses sédimentologiques et micromorphologiques détaillées ainsi que de datations TL sur silex chauffés et IRSL sur feldspaths potassiques. Elle constitue actuellement une nouvelle séquence de référence pédo-sédimentaire pour la France septentrionale pour la fin du Pléistocène moyen (~ 350-140 ka). L’enregistrement comprend cinq luvisols attribués aux SIM 11, 9, 7 et 5e. Deux luvisols sont identifiés pour le SIM 7. Les enregistrements pédo-sédimentaires des SIM 9 et 5 (complexes de sols) sont dilatés et correspondent à la superposition d’un luvisol et d’un pédocomplexe humifère à sol gris forestier (grisol) de contexte Début Glaciaire. Le complexe de sols humifères inférieur attribuable au SIM 9 (« Complexe de sols d’Étricourt ») représente un enregistrement particulièrement détaillé et unique pour le SIM 9 et la transition avec le SIM 8. Un niveau acheuléen situé au-dessus du sol gris forestier du SIM 9 a été daté autour de 288 ± 21 ka par TL sur silex chauffés. Le loess sus-jacent à ce dernier, corrélé au SIM 8, a donné un âge IRSL apparent SIM 7 (215-251 ka) suggérant un remaniement ou une remobilisation du loess au SIM 7. Un niveau paléolithique moyen conservé dans le second luvisol du SIM 7 a été daté à 222 ± 20 ka par TL. Il est surmonté d’un loess primaire allochtone dont les âges IRSL (144-180 ka) confortent son attribution au SIM 6.

La fouille du gisement paléolithique moyen de Mauquenchy (Seine-Maritime) a permis la découverte de niveaux archéologiques bien préservés au sein d’un sol gris-forestier attribué au stade isotopique marin (SIM) 5a. Ce sol contient deux niveaux archéologiques, l’un dans sa partie inférieure (Wa2), le second dans sa partie supérieure (Wa1). Ces deux ensembles archéologiques contenaient chacun un silex taillé chauffé datés par thermoluminescence (83,7 ± 7,6 ka pour Wa2 et 77,6 ± 7,2 ka pour Wa1). Ces datations offrent pour la première fois une possibilité de calage précis de ce sol qui avait été préalablement attribué au SIM 5a sur la base de sa signature interstadiaire. The excavation of the Middle Palaeolithic site of Mauquenchy (Seine-Maritime) led to the discovery of well preserved archaeological levels in a grey forest soil attributed to the marine isotopic stage (MIS) 5a. This soil contains two archaeological levels, one at the bottom (Wa2), the second in its upper part (Wa1). Both sets contain archaeological heated flint dated by thermoluminescence (83.7 ± 7.6 ka for Wa2 and 77.6 ± 7.2 ka Wa1). These ages provide for the first time a precise timing for this soil that had previously been assigned to MIS 5a on the basis of its interstadial signature.

International audience; New Palaeolithic sites are rare for MIS 11 to 9 in Eurasia. The discovery and the excavation of a large new site in 2012 at Etricourt-Manancourt (Somme, France) is an exceptional event. In 2010, a Palaeolithic evaluation was undertaken at a future retention basin by Emilie Goval on 170,000 square metres. The evaluation produced many flint artefacts, demonstrating the existence of at least two important Middle Palaeolithic sites. In 2012, an excavation on one of the sites was conducted by David Herisson over 6 months and covering 4500 square metres. This excavation was undertaken by a multidisciplinary scientific team, including prehistorians and geomorphologists. This allows us to apply a reliable chronostratigraphic approach based on the analysis of the Glacial-interglacial successions. Five in situ Palaeolithic occupations have been excavated, dating from 330 to 70 ka. The youngest occupation dates from 70 to 80 ka (Weichselian) and corresponds to a recent phase of the Middle Palaeolithic. The next two layers belong to the Early Middle Palaeolithic, between 190 and 240 ka (Saalian). Finally, the two oldest layers have dates between 330 and 280 ka (Saalian) and belong to the Lower Palaeolithic. In addition to the archaeology, the sedimentary sequence is very thick (11 m high) and presents for the first time in Northern France a detailed record of the three last interglacial-glacial cycles. This paper presents the first archaeological and chronostratigraphic results of the excavation of Etricourt-Manancourt and its input with high resolution data to discuss behavioural changes occurring at the end of the Lower Palaeolithic and the onset of the Middle Palaeolithic. (C) 2016 Elsevier Ltd and INQUA. All rights reserved.

International audience; In Northern France the loess cover from the Last Glacial (Weichselian) is represented by a subcontinuous cover rising up to 8-9 m in thickness in the best locations as leeward slopes (E-NE exposition). In this large area, pedostratigraphic sequences from the Last Interglacial-glacial cycle (Eemian-Weichselian) have been intensely studied, especially in the frame of very active rescue archaeological programs that have provided hundreds of individual sequences from test-pits or excavations. In spite of variations in the thickness of the different stratigraphic units, driven by differences in geomorphological contexts and in location of the profiles regarding to sources of aeolian material, the pedostratigraphic sequences from the last Interglacial-glacial cycle exhibit a particularly constant pedosedimentary pattern including well identified pedological and periglacial marker horizons that can be followed towards the East in Belgium, in Germany and even in Central-Europe.The main objective of the presentation is to propose a summary of the pedostratigraphic sequence from Northern France and a global correlation scheme with surrounding areas. The great homogeneity that is evidenced in the response of Western European environments to rapid climatic changes provides a solid base for the discussion of relations between man, climate and environment since the Eemian Interglacial. In Northern France, the synthesis of the observations carried out on no more than 80 sequences during the last 20 years allows to draw a highly detailed pedostratigraphic and chronostratigraphic scheme that represents a unique database to discuss the relations between Palaeolithic occupations and environment. This frame can be summarised by the succession of four main chrono-climatic phases that follow the erosion of the interglacial brown leached soil (Eemian) during MIS 5d:1. Early-glacial (112-72 ky): including a phase with grey forest soils (Early-glacial A: ~MIS 5a-5d GIS interstadials 21-24) and a phase with steppe-like soils (Early-glacial B: end of MIS 5a GIS 19 & 20).2. Lower Pleniglacial (~70-58 ky): first typical homogeneous loess deposits marking the first occurrence of typical periglacial conditions.3. Middle Pleniglacial (~ 58-30 ky): intense and short erosive episode (thermokarst)/deposition of thick body of bedded colluviums reworking the whole underlying units/development of a soil, or of a soil complex (Saint-Acheul-Villiers-Adam Complex) during most of MIS 3.4. Upper Pleniglacial (~30-15 ky): main network of large ice-wedge casts/drastic acceleration of loess sedimentation (mainly between 27 and 22 ky) including tundra-gley horizons and large Ice wedge casts.In this context, the data concerning the last climatic cycle (Eemian-Weichselian) show that Human occupation of Northern France was clearly discontinuous, with a clear concentration of remains during the Early-glacial in forest-steppe contexts developed under continental climate. Only a few occupations were attributed to the Lower Pleniglacial and to the course of the MPGL. A total abandon of the region is attested between ca. 25 and ca. 15 ky mainly during the period of maximal loess deposition. Given these results there appears to be a strong relationship between the intensity of human occupation and the climatic and environmental context. This relationship appears to be conditioned by the relative abundance of large fauna, itself linked to vegetation density, as indicated by the extremely sparse biomass contemporaneous with the UPGL loess.

International audience; In connection with the future Canal Seine-Nord Europe (Seine-Scheldt), a large-scale rescue archaeological survey was conducted between 2008 and 2011 in northern France. At Havrincourt (Pas-de-Calais), the discovery of several levels of Palaeolithic flint artefacts embedded in a relatively thick loess sequence (~ 6-7m) preserved on a gentle slope facing north-east, has resulted in a rescue archaeological excavation on a total surface of 6 000 m2. Four Palaeolithic levels were uncovered in primary position. This sequence has been the subject of a continuous stratigraphic survey over nine months and an interdisciplinary approach combining pedostratigraphy, sedimentology, micromorphology, palaeontology, malacology, environmental magnetism, OSL and 14C dating. Based on this research, we propose: 1) a new pedostratigraphic reference sequence for Northern France, especially with regard to the Lower and Middle Pleniglacial periods (~ 70-30 ka), 2) a new regional geochronological framework for the Last Glacial (luminescence and radiocarbon) as well as a revision of the regional pedostratigraphic and chrono-climatic systems, and 3) the description and dating of a unique succession of periglacial horizons including five ice-wedge cast networks associated with tundra gley horizons representing a first regional reference sequence. In addition, the good preservation of archaeological levels, associated with the multidisciplinary analysis and dating of the pedosedimentary sequences leads to the chronostratigraphic and chrono-climatic interpretation of the four Palaeolithic levels including a unique occupation related to the Early Upper Palaeolithic (Early Gravettian). These results and new discoveries allow us to propose Havrincourt as a new pedostratigraphic and archaeological reference sequence for the Late Pleistocene of northern France and more broadly for the west-European loess area.; Dans le cadre des travaux préalables au creusement du futur Canal Seine-Nord-Europe (liaison Seine-Escaut), une opération de diagnostic archéologique de grande ampleur a été menée entre 2008 et 2011 dans le nord de la France. A Havrincourt (Pas-de-Calais), la découverte de plusieurs niveaux de silex paléolithiques inclus dans une séquence loessique relativement épaisse (~ 6-7m) préservée sur un versant en pente douce exposé nord-est a débouché sur une opération de fouille sur une surface totale de 6 000 m2. Quatre niveaux paléolithiques en position primaire ont été mis au jour. Cette séquence a fait l’objet d’un travail de suivi stratigraphique en continu sur plus de neuf mois et d’une approche interdisciplinaire associant pédostratigraphie, sédimentologie, micromorphologie, paléontologie, malacologie, magnétisme environnemental, datations OSL et 14C. Sur la base de ces recherches, nous proposons : 1) une nouvelle séquence pédostratigraphique de référence pour le nord de la France, notamment en ce qui concerne le début du Pléniglaciaire inférieur et le Pléniglaciaire moyen (˷ 70-30 ka), 2) un nouveau canevas géochronologique régional pour le Dernier Glaciaire (datations par luminescence et radiocarbone) ainsi qu’une révision du schéma pédostratigraphique et chrono-climatique régional, et 3) la description et la datation d’une succession unique d’horizons périglaciaires comportant cinq réseaux de fentes associés à des gleys de toundra qui constitue une première séquence régionale de référence. Par ailleurs, la bonne conservation des niveaux archéologiques, associée à l’analyse pluridisciplinaire de la séquence pédosédimentaire et aux datations, débouche sur le calage chronostratigraphique et chrono-climatique précis des quatre niveaux paléolithiques fouillés incluant un ensemble exceptionnel attribuable au Paléolithique supérieur ancien (Gravettien ancien). Ces résultats et découvertes font d’Havrincourt une nouvelle séquence pédostratigraphique et archéologique de référence pour le Pléistocène supérieur de la France septentrionale et plus largement pour la zone loessique ouest-européenne.