ESR/U-series dating Eemian human occupations of Northern France

ESR/U-series dating of Eemian human occupations of Northern France Jean-Jacques Bahain, Samer Farkh, Christophe Falguères, Qingfeng Shao, Pierre Voinchet, Bassam Ghaleb, David Hérisson, Jean-Luc Locht, Nicole Limondin-Lozouet, Patrick Auguste, et al. To cite this version: Jean-Jacques Bahain, Samer Farkh, Christophe Falguères, Qingfeng Shao, Pierre Voinchet, et al.. ESR/U-series dating of Eemian human occupations of Northern France. Quaternary Geochronology, 2022, 71, pp.101305. �10.1016/j.quageo.2022.101305�. �hal-03653032� HAL Id: hal-03653032 https://hal.science/hal-03653032 Submitted on 13 Jan 2023 HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Quaternary Geochronology 71 (2022) 101305 Contents lists available at ScienceDirect Quaternary Geochronology journal homepage: www.elsevier.com/locate/quageo ESR/U-series dating of Eemian human occupations of Northern France Jean-Jacques Bahain a, *, Samer Farkh a, b, Christophe Falguères a, Qingfeng Shao c, Pierre Voinchet a, Bassam Ghaleb d, David Hérisson e, Jean-Luc Locht f, g, Nicole Limondin-Lozouet g, Patrick Auguste h, Agnès Gauthier g, Julie Dabkowski g, Laurent Deschodt g, i, Pierre Antoine g a Histoire Naturelle de l’Homme Préhistorique UMR7194 HNHP, MNHN-CNRS-UPVD, Paris, France Lebanese University, Beirut, Lebanon College of Geography Science, Nanjing Normal University, Nanjing, 210023, China d GEOTOP, Université du Québec à Montréal, Montréal, Canada e Archéologie et Sciences de l’Antiquité UMR7041 ArScAn, CNRS, Nanterre, France f INRAP, Glisy, France g Laboratoire de Géographie Physique, Environnements Quaternaires et Actuels, UMR 8591, CNRS - Université Paris 1 Panthéon-Sorbonne - UPEC, Meudon, France h CNRS, Univ. Lille UMR 8198 – Evo-Eco-Paleo, F-59000, Lille, France i INRAP, Villeneuve d’Ascq, France b c A R T I C L E I N F O A B S T R A C T Keywords: Eemian ESR/U-series Teeth Caours Waziers Palaeolithic sites associated with the Eemian Interglacial (MIS 5e) are very rare in NW Europe, and especially in Northern France, where their preservation is restricted to very specific geological contexts, in association with carbonated tufa (Caours) or peat deposits (Waziers). In order to check the reliability of ESR/U-series method to date teeth recovered from archaeological levels in such specific geological environments, teeth were sampled on these two Middle Palaeolithic sites and systematic in situ dosimetry was performed using portable gamma spectrometer. The ESR/U-series ages obtained on the Caours site are very homogeneous allowing the calculation of a mean age equal to 125 ± 11 ka, in agreement with the geological age, mammal’s association and other available geochronological data (U-series on tufa carbonate, TL on burnt flints, OSL on sediments), despite a relatively heterogeneous dosimetric environment (gamma dose rate ranging between ca 200–450 μGy/a). At Waziers, reducing (water logging) environment linked to the peat leads to very specific U-series data of the analysed teeth (U content lower than 0.1 ppm in all the dental tissues, evidence of leaching in some tissues), but the mean ESR/U-series age, 129 ± 4 ka, is also in agreement with the available geological and palaeoenvironmental data indicating that the dated teeth were associated with Late Glacial deposits prior to the climatic interglacial optimum. These two case studies then confirm the reliability of ESR/U-series method to date with good reliability and accuracy the archaeological levels linked to such relatively short climatic events (ca 10 ka). 1. Introduction Since the late 1980s, ESR/U-series dating method has been used to date Middle Palaeolithic sites of Western Europe, alone or in combina­ tion with other geochronological methods. The method was particularly applied on teeth recovered from sites in Northern France, where the age of the archaeological levels is often well constrained by stratigraphical or paleoenvironmental data (e.g. Bahain et al., 2010, 2012, 2015, 2020; Antoine et al., 2016, 2021; Guérin et al., 2017). Despite a relatively poor precision by comparison to 14C or OSL results, ESR/U-series data usually enable to correlate the dated levels to a given marine isotopic stage and participate hence to the construction of a unified regional chro­ nostratigraphical framework (Bahain et al., 2007; Antoine et al., 2000, 2007, 2014; Voinchet et al., 2015). However, this poor precision can be a limitation to date levels associated to relatively short climatic or geological events, such as Late Pleistocene Greenland stadials and in­ terstadials (Rasmussen et al., 2014) or the last interglacial stage (MIS 5e, ca 129–116 ka, Sakari Salonen et al., 2018), called Eemian in northern * Corresponding author. E-mail address: [email protected] (J.-J. Bahain). https://doi.org/10.1016/j.quageo.2022.101305 Received 26 November 2021; Received in revised form 29 March 2022; Accepted 3 April 2022 Available online 9 April 2022 1871-1014/© 2022 Elsevier B.V. All rights reserved. J.-J. Bahain et al. Quaternary Geochronology 71 (2022) 101305 Fig. 1. Location of the studied sites in northern France. Fig. 2. Summary of stratigraphic and palaeoenvironmental data available from the two studied Eemian sites from northern France (Caours and Waziers). The analysed teeth were recovered from archaeological levels N1 and N3 at Caours and from units U4c-d and U4–U5 limit at Waziers. European chronostratigraphy (Cohen and Gibbard, 2019). Palaeolithic sites associated with the Eemian interglacial (MIS 5e) are very rare in northern France Quaternary sequences owing to the major erosion processes occurring during the early stages of the subse­ quent Weichselian period (Antoine et al., 2016). In the 1980s some re­ searchers considered even a lack of human presence in North-Western Europe during this interglacial (Gamble, 1896). In northern France, only two Eemian sites have been discovered so far and are currently excavated: Caours (Somme) and Waziers (Nord) (Fig. 1) (Locht et al., 2014, 2016; Hérisson, 2016). 2016) and Locht et al. (2014, 2016), the main part of these sites has probably been destroyed or displaced during the earliest cold events of the Weichselian, beginning ca 116 ka ago (Sakari Salonen et al., 2018). Until the beginning of the 2000s, the Eemian archaeological evidences in northern France loess-palaeosol sequences were hence restricted to materials reworked by erosion (Antoine et al., 2002). Known since the XIXth century (Prestwich et al., 1864), the Caours site was rediscovered in 2002 (Antoine et al., 2006), in the frame of a research program focusing on interglacial deposits in the Somme terraces system (Antoine et al., 2007). The subsequent discovery of the Waziers locality in 2011 during a campaign of rescue survey, definitively demonstrated that human groups were present in northern France during the Eemian (Locht et al., 2014, 2016; Hérisson, 2016). The Caours site, located close to Abbeville in the Scardon Valley, a small tributary of the Somme River, was known since the 1940s (Aufrère, cited in Breuil, 1952; Bourdier, 1969), but never really studied and published at that time. The new investigation since 2002 shows that 2. Site presentation and sampling As mentioned previously, Eemian archaeological sites are quite rare in northern France, which probably does not reflect the absence of human groups in this area at this time but rather taphonomic issues (Roebrocks and Speleers, 2002). As explained by Antoine et al. (2002, 2 J.-J. Bahain et al. Quaternary Geochronology 71 (2022) 101305 the site is characterized by a thick calcareous tufa formation (3–4 m) overlying periglacial fluvial flint gravels attributed to the penultimate glacial stage (Saalian, MIS 6) (Fig. 2) (Antoine et al., 2006, 2007; Dab­ kowski et al., 2015, 2016). The lower part of the Caours stratigraphical sequence fossilized four archaeological levels (Antoine et al., 2006; Locht et al., 2016) containing abundant Middle Palaeolithic artefacts. The associated interglacial faunal remains correspond to a well-developed forested temperate environment where some open area spaces as meadows persisted (Auguste, 2009). Uranium-series (U-series) on carbonates, themoluminescence (TL) on heated flints and optically stimulated luminescence (OSL) on sediments dates constrain the tufa formation and Caours archaeological levels to 123 ± 3 ka, allowing their attribution to the Eemian (Antoine et al., 2006, 2007; Antoine and Locht, 2015). The malacofauna study permits to precise the position of the Eemian climatic optimum in the lower part of the tufa formation (units 4–10), the lowest part of the sequence being assigned to the late Saalian glacial (unit 11) and the top of the tufa (units 1–3) related to a climate drying during the subsequent interglacial stage (Limondin-Lo­ zouet, in Antoine et al., 2006; Limondin-Lozouet, 2011; Limondin-Lo­ zouet and Preece, 2014). Five teeth from the interglacial part of the sequence, four from archaeological level N1 (unit 5) and one from N3 (unit 9), were sampled and analysed in the present work by combined electron spin resonance and U-series dating method (ESR/U-series). Another tooth from N1 level was previously dated by the same method to 124 ± 15 ka (Bahain et al., 2010). Waziers is located close to Douai, in the Scarpe river valley. The site was discovered during archaeological survey operation in 2011 and 2013, a first sector being excavated in 2014–2015 (Hérisson, 2016). The stratigraphic sequence (Fig. 2) encloses coarse fluvial deposits (sands and gravels) recovered by calcareous silts, organic silts and peat levels infilling a large palaeo-meander channel of the Scarpe River and then covered by chalky gravels and finally by sandy loess deposits (Deschodt, in Hérisson, 2016). The organic silts and peat layers yielded four archaeological levels (N0–N3) with some Middle Palaeolithic flint ar­ tefacts associated with large mammal remains including well preserved mammal teeth. U-series minimum age (103 + 3,5/-3,4 ka) on char­ ophyte gyrogonite extracted from calcareous sandy silt at the very base of the interglacial sequence infilling the channel (Ghaleb, in Hérisson, 2016) and the malacological study (Limondin-Lozouet, in Hérisson, 2016) indicate the Pleistocene age of the sequence. Malacological and mainly palynological data (Gauthier, in Hérisson, 2016) allow the description of a vegetation dynamic corresponding to the transition between a late glacial stage and an interglacial stage, then to an inter­ glacial record. Indeed they demonstrate both open landscape and cold environment in the fluvial deposits of the bottom of the sequence (units 3 and 4). Then, temperate environment conditions are recorded through the successive development of pioneer trees then of deciduous forest phases (Ulmus, Quercus, Corylus, lastly Carpinus as dominant trees) cor­ responding to an interglacial while locally the site progress from a peat bog to a swamp forest. The mammal fauna associated to these inter­ glacial levels is, as at Caours, typical of a forested environment, while species characteristics of more open area as equids were recovered in the lower silty fluvial deposits and the position of the site in the valley as well as the presence of Middle Palaeolithic industry in several levels has allowed the attribution of the stratigraphic sequence to the late glacial phasis of the Saalian glacial (MIS 6) and to the Eemian interglacial (Auguste, in Hérisson, 2016). In the present work, four teeth from Waziers, coming from the late glacial fluvial deposits, were analysed, three from unit 4c-d and one at the boundary between units 4 and 5 (Fig. 2). 3. Methods and protocols ESR/U-series dating method was applied using the protocol of preparation and analyses described in Bahain et al. (2010). Enamel layers were mechanically extracted from the teeth and cleaned using a dentist drill to remove dentine or sediment contamination. The clean enamel sample was then ground and the 100–200 μm grain-size fraction was split into 10 (Caours) of 14 (Waziers) aliquots. One aliquot was kept as “natural” reference and the other aliquots were gamma irradiated at doses ranging from 50 to 2,000 Gy (Caours, IBL 60Co source, CEN Saclay, France) or from 25 to 6,300 Gy (Waziers, Gammacell 137Cs source, CENIEH, Burgos, Spain) with a dose rate of about 200 Gy/h. The ESR intensity of each aliquot was then measured using a Bruker EMX spectrometer at room temperature using X band (frequency mod­ ulation of 100 kHz) at MNHN, Paris, France. The following parameters were used for the measurements: microwave power of 10 mW, modu­ lation amplitude of 0.1 mT, scan range of 10 mT, scan time of 4 min. At least four measurements were performed for each aliquot on different days. The ESR intensities of the radiation-induced of the enamel signal at g = 2.00018 were measured peak-to-peak (T1-B2) according to Grün (2000). Equivalent doses were determined from the obtained dose-intensity data points using single exponential function with 1/I2 weighting. U-series analyses were performed on each dental tissue, by alpha spectrometry (Caours samples) at MNHN, Paris, after chemical prepa­ ration preconized by Bischoff et al. (1988), or by Multi-Collector Inductively Coupled Plasma Mass Spectrometer (Neptune MC-ICPMS) (Waziers samples) at Nanjing Normal University, China with the chemical protocol of Shao et al. (2015a). Eventual radon loss was determined from each tissue by combining alpha-ray and gamma-ray data (Bahain et al., 1992). U-series data are displayed Table 1. Table 1 U-series data obtained on the dental tissues of the analysed teeth from two Eemian sites of Northern France (Caours and Waziers). The ages are calculated with 1 σ error range. Sample Level Tissue U (ppm) 230 Th/232Th CA-0501 US 5 - N1 CA-0502 US 5 - N1 CA-0503 US 5 - N1 CA-0701 US 5 - N1 CA-0504 US 9 – N3 WBT-138 limit US4-US5 WBT-19 US 4c-d WBT-22-1 US 4c-d WBT-22-2 US 4c-d Enamel Dentine Enamel Dentine Enamel Dentine Enamel Dentine Enamel Dentine Enamel Dentine Enamel Dentine Enamel Dentine Enamel Dentine 0.332 ± 0.020 8.235 ± 0.220 0.301 ± 0.017 6.560 ± 0.219 0.393 ± 0.029 10.270 ± 0.242 0.338 ± 0.016 5.281 ± 0.165 0.193 ± 0.012 13.771 ± 0.316 0.070 ± 0.001 0.068 ± 0.001 0.036 ± 0.001 0.097 ± 0.001 0.071 ± 0.001 0.028 ± 0.001 0.009 ± 0.001 0.015 ± 0.001 12 318 16 90 23 133 8 113 13 67 344 13 46 128 213 16 30 145 234 U/238U 1.376 ± 1.281 ± 1.247 ± 1.232 ± 1.063 ± 1.167 ± 1.274 ± 1.229 ± 1.222 ± 1.225 ± 1.175 ± 1.354 ± 1.467 ± 1.609 ± 1.246 ± 1.348 ± 1.386 ± 1.508 ± 3 0.094 0.032 0.075 0.044 0.094 0.026 0.066 0.014 0.090 0.021 0.002 0.006 0.017 0.004 0.005 0.005 0.011 0.007 230 Th/234U 0.927 1.342 0.813 1.419 0.953 1.150 0.923 1.008 0.884 1.135 0.687 0.679 0.600 0.547 0.775 0.655 0.672 0.555 ± 0.086 ± 0.052 ± 0.078 ± 0.080 ± 0.102 ± 0.042 ± 0.055 ± 0.052 ± 0.087 ± 0.048 ± 0.003 ± 0.004 ± 0.009 ± 0.002 ± 0.004 ± 0.004 ± 0.008 ± 0.0043 222 Rn/230Th Apparent U-series age (ka) 1.00 0.17 0.55 0.32 1.00 0.16 0.92 0.14 1.00 0.09 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 220 ± 97 >300 166 ± 48 >300 299 ± 150 >300 226 ± 62 327 ± 172 205 ± 96 >300 121 ± 1 111 ± 3 93 ± 2 81 ± 1 150 ± 2 106 ± 2 111 ± 3 83 ± 1 J.-J. Bahain et al. Quaternary Geochronology 71 (2022) 101305 Table 2 Radioelements contents of sediments associated to the analysed teeth from two Eemian sites of Northern France (Caours and Waziers). Sample Level 238 CA-0501 CA-0502 CA-0503 CA-0701 CA-0504 WBT-138 WBT-19, 22–1 & 22-2 US 5 - N1 US 5 - N1 US 5 - N1 US 5 - N1 US 9 – N3 Limit US 4-5 US 4c-d 0.627 1.072 0.383 0.286 1.219 0.379 0.558 232 U (ppm) ± 0.093 ± 0.123 ± 0.071 ± 0.046 ± 0.102 ± 0.085 ± 0.077 1.002 3.887 0.130 0.671 6.242 3.249 3.340 The dose rate was estated from measurements by gamma-ray spec­ trometry in laboratory from 100 g of sediments corresponding to the analysed teeth with a low background high purity germanium (HPGe) detector (Table 2). No disequilibrium in the natural radioactive chains was observed in the sediments of the two sites. Water content of sedi­ ments was previously measured for each dated level by drying it in oven at 40 ◦ C during one week. The cosmic dose rate was estimated using the formula of Prescott and Hutton (1994). In situ measurements were also performed using Canberra Inspector1000 spectrometer (Mercier and Falguères, 2007): at Caours, which is a yearly excavated site, these measurements were made in the immediate vicinity of each analysed sample and several measurements were hence performed for the same N1 archaeological level; at Waziers, as the site is close to a road and the sections not conserved for a long time, the in situ dosimetry was performed on the single available section, explaining why only one measurement was performed per dated layer. At Caours, the in situ measurements are globally lower than the dose rates calculated from the radioelement contents of the sediments while at Waziers the data are quite similar for the two kinds of measurements. The U-uptake parameters, dose rate contributions and ESR/U-series ages with their uncertainties were then calculated (see details in Shao et al., 2012, 2014; 2015b). As the U-series results on several dental tissues were older than the corresponding EU-ESR data, it was not possible to systematically apply the US model (Grün et al., 1988) and the accelerating U-uptake (AU) model by Shao et al. (2012), allowing the modelling of U-leaching from some of the tissues, was then used instead. The age calculations were performed using the “AUAGE” and “USESR” computer programs with the following parameters: a k-value (α effi­ ciency) of 0.13 ± 0.02 (Grün and Katzenberger-Apel, 1994); water contents of 0 wt% in the enamel and 7 wt% in the dentine; radioelements content-dose conversion factors of Guérin et al. (2011); beta attenua­ tions values in dental tissues were calculated using a Monte Carlo approach taking into account the enamel thickness removed during the sample preparation (Brennan et al., 1997) (Table 3). Level Initial thickness (μm) Removed thickness Internal side (μm) Removed thickness External side (μm) CA-0501 CA-0502 CA-0503 CA-0701 CA-0504 WBT138 WBT-19 WBT-221 WBT-222 US 5 - N1 US 5 - N1 US 5 - N1 US 5 - N1 US 9 – N3 Limit US 4-5 US 4c-d US 4c-d 867 ± 108 993 ± 124 893 ± 112 957 ± 120 931 ± 230 1250 ± 156 27 ± 3 50 ± 6 79 ± 7 43 ± 5 169 ± 18 38 ± 5 4±1 20 ± 2 4±1 17 ± 2 103 ± 25 135 ± 17 1209 ± 151 1113 ± 139 70 ± 9 55 ± 7 84 ± 11 39 ± 5 US 4c-d 883 ± 110 39 ± 5 75 ± 9 ± 0.164 ± 0.210 ± 0.005 ± 0.053 ± 0.183 ± 0.115 ± 0.107 4 K (%) 0.202 ± 0.859 ± 0.039 ± 0.116 ± 1.169 ± 0.957 ± 0.942 ± Water content (%) 0.011 0.019 0.005 0.005 0.016 0.016 0.014 15 15 15 15 15 28 20 ±5 ±5 ±5 ±5 ±5 ±5 ±5 4. Results and discussion The ESR/U-series results obtained on the teeth from the two Eemian sites of northern France are shown in Table 4, while Fig. 3 displays the dose rate contributions (both in μGy/a and in %) for the different ana­ lysed teeth. Several interesting points can be highlighted in these data: - The Waziers dental tissues display very low uranium contents, < 0.1 ppm in both enamel and dentine of all teeth. Moreover, the enamel often shows higher concentrations than in the corresponding dentine, which is very unusual. This behavior is perhaps linked to the reducing environment associated with the decomposition of the organic plant matter in the peat, leading to the fixation of the ura­ nium in the humic acids of the peat rather than in the paleontological remains, whereas thorium will be absorbed on the detrital particles (Geyh, 2008; Waas et al., 2011); - In consequence of this very specific geochemical behavior, the in­ ternal dose has a restricted impact in the age determination as well as the β dose contribution related to the dentines (<20%) compared to the external (sediment + cosmic) dose (Fig. 3). - By comparison, U contents of the Caours dental tissues range from ~0.19 to ~0.39 ppm in the enamels and from ~5.28 to ~13.77 ppm in the dentines. They correspond to more usual values and leads to a greater contribution of the Caours dental tissues to the dose rate, ranging between 30 and 60%. - U-series analyses reveal on the other hand high 230Th/234U ratios (between 0.813 and 1.342) in the tissues of Caours teeth, leading to apparent U-series ages higher than the EU-ESR age, which indicate a possible U-leaching. - As a consequence, only the AU model was used to calculate ESR/Useries ages for the Caours samples, this model considering an initial U-uptake followed by a U-leaching. This U-leaching could be related to the growth of the overlying tufa formation, implying phases of important water circulation. This leaching, combined with the sig­ nificant errors on the U-series isotopic ratios determined by α-spec­ trometry U-series analyses on the Caours dental tissues, leads to large age uncertainties for some teeth (e.g. CA-0501 and CA-0502). - For the Waziers tissues, the apparent U-series ages are close to the EU-ESR ages (120–130 ka) except for the enamel of tooth WBT-22-1 for which the obtained value is higher. As previously mentioned, this modelling has however not impact on the age calculation due to the poor associated dose contribution. - On each site, the equivalent doses are quite low (Fig. 4). For the Caours samples, the DE range between 50 and 80 Gy, but these variations are counterbalanced by the local variation of external doses, precisely recorded at the sampling location on the site for each tooth. This work demonstrates hence the importance of an accurate in situ dosimetry in the age calculation for such low radioactive environment depending of the repartition of the palaeontological remains that can represent radioactivity hotspots. The ESR/U-series ages for Caours teeth determined using AU model for N1 teeth are relatively homogeneous, ranging from 119 ± 42 ka to 126 ± 37 ka and leading to a mean age of 124 ± 10 ka (±2σ) for level N1 Table 3 Initial and mechanically removed thicknesses of enamel layers during the preparation of the analysed teeth from two Eemian sites of Northern France (Caours and Waziers) prior to ESR/U-series dating. Sample Th (ppm) 4 J.-J. Bahain et al. Quaternary Geochronology 71 (2022) 101305 Table 4 Equivalent doses, U-uptake parameters, contributions to the dose rate and ESR/U-series ages obtained for the analysed teeth from two Eemian sites of Northern France (Caours and Waziers). The ESR-U/series ages are given with ±2 sigma. Sample Level Tissue Equivalent dose DE (Gy) U uptake parameters p (regular) or n (italics) Da α internal (μGy/a) Da β (μGy/a) Da (γ + cosm) (μGy/a) Da total (μGy/a) ESR/U-series ages US (regular) or AU (italics) models (ka) CA-0501 N1– U5 79.31 ± 3.07 185 ± 117 259 ± 21 629 ± 186 126 ± 37 N1– U5 41 ± 37 316 ± 196 210 ± 20 567 ± 201 119 ± 42 CA-0503 N1– U5 121 ± 3 159 ± 10 169 ± 22 449 ± 24 119 ± 15 CA-0701 N1– U5 116 ± 1 74 ± 3 395 ± 20 585 ± 20 125 ± 5 CA-0504 N3–U9 59 ± 2 279 ± 21 210 ± 20 548 ± 29 129 ± 23 WBT-138 Limit US 45 US4c-d − 0.0123 ± 0.0037 − 0.0139 ± 0.0098 − 0.0128 ± 0.0051 +0.0390 ± 0.1431 − 0.0088 ± 0.0005 − 0.0105 ± 0.0005 − 0.0077 ± 0.0001 − 0.0104 ± 0.0002 − 0.0312 ± 0.0057 − 0.0102 ± 0.0008 − 0.9386 ± 0.0461 − 0.9016 ± 0.0479 − 0.7551 ± 0.0608 − 0.5956 ± 0.0711 − 0.0106 ± 0.0010 − 0.8125 ± 0.0502 − 0.9384 ± 0.0438 − 0.6443 ± 0.0608 185 ± 143 CA-0502 Enamel Dentine Enamel Dentine Enamel Dentine Enamel Dentine Enamel Dentine Email Dentine Email Dentine Email Dentine Email Dentine 20 ± 32 89 ± 12 470 ± 23 579 ± 41 132 ± 8 9 ± 22 48 ± 9 408 ± 20 465 ± 33 125 ± 8 21 ± 3 4 ± 42 408 ± 20 433 ± 26 138 ± 8 2 ± 20 69 ± 10 408 ± 20 479 ± 30 123 ± 7 WBT-19 WBT-221 WBT-222 US4c-d US4c-d 67.53 ± 2.66 53.39 ± 5.30 73.16 ± 2.90 71.00 ± 10.62 76.47 ± 2.72 58.08 ± 1.70 59.71 ± 1.03 58.95 ± 1.66 Fig. 3. Dose rate contributions calculated for the analysed teeth of two Eemian sites of northern France (Caours and Waziers). 5 J.-J. Bahain et al. Quaternary Geochronology 71 (2022) 101305 Fig. 4. Dose response curves obtained for the analysed teeth of two Eemian sites of northern France (Caours and Waziers). (calculated with Isoplot, Ludwig, 2003), similar to the age of 124 ± 15 ka obtained previously by Bahain et al. (2010). The tooth ana­ lysed from level N3 provides an AU age of 129 ± 23 ka. Given these very homogeneous ages for the two dated levels, the attribution of the deposit to the Eemian interglacial is confirmed with an ESR/U-series mean age of 125 ± 9 ka. - At Waziers, despite the impossibility to measure so precisely the external dose rate variations due to a more restricted access to the dated level that could explain the scattering of the age results ob­ tained for the limit US 4–5 teeth, the homogeneity of the equivalent doses obtained for the teeth of this level, comprised between 58 and 60 Gy, leads to the calculation of a weighted mean age of 128 ± 20 ka (±2σ), while the higher DE value obtained for the U4c-d level (76 Gy) probably in relation with a more radioactive background, leads to an undistinguishable US age of 132 ± 8 ka. Given these very ho­ mogeneous ages for the two dated levels, a weighted mean age of 129 ± 11 ka (2σ) can be calculated from these four samples. This is in good agreement with the attribution of the deposition of the fluvial silts of Waziers U4 level to the Saalian late glacial and consistent with the available palaeoenvironmental data. collected from two Eemian sites of northern France, Caours and Waziers, demonstrate the reliability of the method to date such Middle Paleolithic sites (Fig. 5). The results also indirectly emphasize the validity of the analytical procedures employed, despite peculiar geochemical charac­ teristics of part of the dental tissues. Finally, this work also shows in particular the importance of the in situ dosimetry measurements in the Caours age calculation. At Caours, the obtained ESR/U-series ages lead to the calculation of a weighted mean age of 125 ± 9 ka in excellent agreement with the other available geochronological data derived from U-series and luminescence studies and dating the overlying tufa formation of 123 ± 3 ka. Associ­ ated to the available palaeoenvironmental, mammal’s association and archaeological data, they make of this site one of the best dated Middle Palaeolithic sequence of France. For Waziers, the newly established ESR/U-series chronology for teeth of Unit 4, with a mean age of 129 ± 11 ka, represents the first numerical age estimate for these levels. It confirms its attribution to the Saalian late glacial stage (MIS6), one more time in close agreement with the palaeoenvironmental data, and allows the attribution to the over­ lying organic fluvial deposits and associated archaeological levels to the Eemian interglacial. Lastly, these results show the interest to integrate ESR/U-series dating analyses during the chronostratigraphical study of such Middle Palaeolithic sites when possible and demonstrate the necessity to 5. Conclusion The combined ESR/U-series analyses performed on fossil teeth 6 J.-J. Bahain et al. Quaternary Geochronology 71 (2022) 101305 Fig. 5. Geochronological correlation of the obtained ESR/U-series mean ages for two Eemian sites of northern France (Caours and Waziers) with the Marine isotopic record of Lisiecki and Raymo (2005). involve geochronologists to the fieldworks and excavations, since the earliest stages of study. model of the Somme valley (France) and the neigh1bouring regions. In: ArnaudFassetta, G., Carcaud, N. (Eds.), French Geoarchaeology in the 21st Century. CNRS éditions, Paris, pp. 71–86. Antoine, P., Moncel, M.-H., Limondin-Lozouet, N., Locht, J.-L., Bahain, J.-J., Moreno, D., Voinchet, P., Auguste, P., Stoetzel, E., Dabkowski, J., Bello, S.M., Parfitt, S.A., Tombret, O., Hardy, B., 2016. Palaeoenvironment and dating of the early Acheulean localities from the Somme River basin (northern France): new discoveries from the high terrace at Abbeville-Carrière Carpentier. Quat. Sci. Rev. 149, 338–371. Antoine, P., Coutard, S., Bahain, J.-J., Locht, J.-L., Hérisson, D., Goval, E., 2021. The last 750 ka in loess-palaeosols sequences from Northern France: environmental background and dating of the Western European Palaeolithic. J. Quat. Sci. https:// doi.org/10.1002/jqs.328. Auguste, P., 2009. Evolution des peuplements mammaliens en Europe du nord-ouest durant le Pléistocène moyen et supérieur. Le cas de la France septentrionale. Quaternaire 20, 527–550. Bahain, J.-J., Yokoyama, Y., Falguères, C., Sarcia, M.N., 1992. ESR dating of tooth enamel: a comparison with K-Ar dating. Quat. Sci. Rev. 11, 245–250. Bahain, J.-J., Falguères, C., Laurent, M., Voinchet, P., Dolo, J.-M., Antoine, P., Tuffreau, A., 2007. ESR chronology of the Somme River Terrace system and first human settlements in Northern France. Quat. Geochronol. 2, 356–362. Bahain, J.-J., Falguères, C., Dolo, J.-M., Antoine, P., Auguste, P., Limondin-Lozouet, N., Locht, J.-L., Tuffreau, A., 2010. ESR/U-series dating of teeth recovered from wellstratigraphically age-controlled sequences from Northern France. Quat. Geochronol. 5, 371–375. Bahain, J.-J., Falguères, C., Laurent, M., Shao, Q., Dolo, J.-M., Garcia, T., Douville, E., Frank, N., Monnier, J.-L., Hallegouët, B., Laforge, M., Huet, B., Auguste, P., Liouville, M., Serre, F., Gagnepain, J., 2012. ESR and ESR/U-series dating study of several middle palaeolithic sites of Pléneuf-Val-André (Brittany, France): Piégu, Les Vallées and Nantois. Quat. Geochronol. 10, 424–429. Bahain, J.-J., Falguères, C., Laurent, M., Dolo, J.-M., Shao, Q., Auguste, P., Tuffreau, A., 2015. ESR/U-series dating of faunal remains from the paleoanthropological site of Biache-Saint-Vaast (Pas-de-Calais, France). Quat. Geochronol. 30, 541–546. Bahain, J.-J., Duval, M., Voinchet, P., Tissoux, H., Falguères, C., Grün, R., Moreno, D., Shao, Q., Tombret, O., Jamet, G., Faivre, J.-P., Cliquet, D., 2020. ESR and ESR/Useries chronology of the Middle Pleistocene site of Tourville-la-Rivière (Normandy, France) - a multi-laboratory approach. Quat. Int. 556, 66–78. Bischoff, J.L., Robert, J., Rosenbauer, R.J.V., 1988. A test of Uranium-series dating of fossil tooth enamel: result from Tournal Cave, France. Appl. Geochem. 3, 145–151. Brennan, B.J., Rink, W.J., McGuirl, E.L., Schwarcz, H.P., Prestwich, W.V., 1997. Beta doses in tooth enamel by ‘‘One Group’’ theory and the Rosy ESR dating software. Radiat. Meas. 27, 307–314. Bourdier, F., 1969. Étude comparée des dépôts quaternaires des bassins de la Seine et de la Somme. Bull. Inf. Geol. Bassin Paris 21, 169–231. Breuil, H., 1952. Glanes conchyliologiques en France (Nord et Sud-Ouest) déterminées par S. Kenard. In: Compte rendu de la XIIIe Session du Congrès Préhistorique de France. Société préhistorique de France, pp. 191–240. Cohen, K.M., Gibbard, P., 2019. Global chronostratigraphical correlation table for the last 2.7 million years, version 2019 QI-500. Subcommission on quaternary stratigraphy (International Commission on stratigraphy), Cambridge, England. Quat. Int. 500, 20–31. Dabkowski, J., Royle, S.H., Antoine, P., Marca-Bell, A., Andrews, J.E., 2015. Highresolution δ18O seasonality record in a French Eemian tufa stromatolite (Caours, Somme basin). Palaeogeogr. Palaeoclimatol. Palaeoecol. 438, 277–284. Dabkowski, J., Limondin-Lozouet, N., Andrews, J., Marca-Bell, A., Antoine, P., 2016. Climatic and environmental variations during the last interglacial recorded in a Northern France tufa (Caours, Somme basin). Comparisons with regional records. Quaternaire 27, 249–261. Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgements We would like to thank the Caours and Waziers excavation teams for their availability, patience and helpful discussions. The present study was financially supported by the UMR7194 HNHP which allowed the funding of the field missions and analyses, with the help of the PCR PaléHauts funded by the SRA Hauts-de-France. The ESR and mobile gamma-ray spectrometers of the French National Museum of Natural History were bought with the financial support of the ‘Sesame Île-deFrance’ program and the ‘Région Centre’ respectively. U-series analysis in NNU was supported by the National Natural Science Foundation of China (grant 41877430). Lastly we would thank Renaud Joannes-Boyau and Mathieu Duval for their valuable and pertinent comments which have allowed a great improvement of the manuscript. References Antoine, P., Locht, J.-L., 2015. Chronostratigraphie, paléoenvironnements et peuplements au Paléolithique moyen : les données du Nord de la France. In: Depaepe, P., Goval, E., Koehler, H., Locht, J.-L. (Eds.), Les plaines du Nord-Ouest : carrefour de l’Europe au Paléolithique moyen, Mémoire de la Société préhistorique française, vol. 59, pp. 11–23. Antoine, P., Lautridou, J.P., Laurent, M., 2000. Long-Term fluvial archives in NW France: response of the Seine and Somme Rivers to tectonic movements, climatic variations and sea level changes. Geomorphology 33, 183–207. Antoine, P., Frechen, M., Locht, J.-L., Munaut, A.-V., Rousseau, D.-D., Sommé, J., 2002. Eemian and Weichselian early-glacial pedosedimentary records in Northem France: the background of middle palaeolithic occupations during OIS 5 and early OSI4. In: Tuffreau, A., Roebroeks, W. (Eds.), Le Dernier Interglaciaire et les occupations humaines du Paléolithique moyen, vol. 8. Publication du Publications du Centre d’Etudes et de Recherches Préhistoriques, Lille, pp. 75–88. Antoine, P., Limondin-Lozouet, N., Auguste, P., Locht, J.-L., Ghaleb, B., Reyss, J.L., Escudé, E., Carbonel, P., Mercier, N., Bahain, J.-J., Falguères, C., Voinchet, P., 2006. Le site de Caours (Somme/France) : mise en évidence d’une séquence de tuf contemporaine du dernier interglaciaire (Eemien) et d’un gisement paléolithique associé. Quaternaire 17 (4), 281–320. Antoine, P., Limondin Lozouet, N., Chaussé, C., Lautridou, J.-P., Pastre, J.-F., Auguste, P., Bahain, J.-J., Falguères, C., Ghaleb, B., 2007. Pleistocene fluvial terraces from northern France (Seine, Yonne, Somme): synthesis, and new results from interglacial deposits. Quat. Sci. Rev. 26, 2701–2723. Antoine, P., Locht, J.-L., Limondin-Lozouet, N., Auguste, P., Bahain, J.-J., Fagnart, J.-P., Debenham, N., Ducrocq, T., 2014. Quaternary geoarcheology and Prehistory: the 7 J.-J. Bahain et al. Quaternary Geochronology 71 (2022) 101305 Prescott, J.R., Hutton, J.T., 1994. Cosmic ray contributions to dose rates for luminescence and ESR dating: large depths and long-term time variations. Radiat. Meas. 23, 497–500. Prestwich, J., 1864. On some further evidence bearing on the excavation of the valley of the Somme by river-action, as exhibited in a section at Drucat near Abbeville. Proc. Roy. Soc. Lond. 13, 135–137. Rasmussen, S.O., Bigler, M., Blockley, S.P., Blunier, T., Buchardt, T., Clausen, H.B., Cvijanovic, I., Dahl-Jensen, D., Johnsen, S.J., Fischer, H., Gkinis, V., Guillevic, M., Hoek, W.Z., Lowe, J.J., Pedro, J.B., Popp, T., Seierstad, I.K., Steffensen, J.P., Svensson, A.M., Vallelonga, P., Vinther, B.M., Walker, M.J.C., Wheatley, J.J., Winstrup, M., 2014. A stratigraphic framework for abrupt climatic changes during the Last Glacial period based on three synchronized Greenland ice-core records: refining and extending the INTIMATE event stratigraphy. Quat. Sci. Rev. 106, 14–28. Roebroeks, W., Speleers, B., 2002. Last interglacial (Eemian) occupation of the north European plain and adjacent areas. In: Tuffreau, A., Roebroeks, W. (Eds.), Le Dernier Interglaciaire et les occupations humaines du Paléolithique moyen, vol. 8. Publication du Publications du Centre d’Etudes et de Recherches Préhistoriques, Lille, pp. 31–39. Sakari Salonen, J., Helmens, K.F., Brendryen, J., Kuosmanen, N., Valiranta, M., Goring, S., Korpela, Mikko, Kylander, M., Philip, A., Plikk, A., Renssen, H., Luoto, M., 2018. Abrupt high-latitude climate events and decoupled seasonal trends during the Eemian. Nat. Commun. 9, 2851. Shao, Q., Bahain, J.-J., Falguères, C., Dolo, J.-M., Garcia, T., 2012. A new U-uptake model for combined ESR/U-series dating of tooth enamel. Quat. Geochronol. 10, 406–411. Shao, Q., Bahain, J.J., Dolo, J.M., Falguères, C., 2014. Monte Carlo approach to calculate US-ESR ages and their uncertainties. Quat. Geochronol. 22, 99–106. Shao, Q., Bahain, J.-J., Wang, W., Jin, C., Wang, Y., Voinchet, P., Lin, M., 2015a. Combined ESR and U-series dating of early Pleistocene gigantopithecus faunas at Mohui and Sanhe Caves, Guangxi, southern China. Quat. Geochronol. 30, 524–528. Shao, Q., Chadam, J., Grün, R., Falguères, C., Dolo, J.-M., Bahain, J.-J., 2015b. The mathematical basis for the US-ESR dating method. Quat. Geochronol. 30, 1–8. Voinchet, P., Moreno, D., Bahain, J.-J., Tissoux, H., Tombret, O., Falguères, C., Moncel, M.-H., Schreve, D., Candy, I., Antoine, P., Ashton, N., Beamish, M., Cliquet, D., Despriée, J., Lewis, S., Limondin-Lozouet, N., Locht, J.-L., Parfitt, S., Pope, M., 2015. New chronological data (ESR and ESR/U-series) for the earliest Acheulian sites of northwestern Europe. J. Quat. Sci. 30 (7), 610–622. Waas, D., Kleinmann, A., Lepper, J., 2011. Uranium-series dating of fen peat horizons from pit Nachtigall in northern Germany. Quat. Int. 241, 111–124. Gamble, C.S., 1896. The Palaeolithic Settlement of Europe. Cambridge University Press, Cambridge, p. 471. Geyh, M.A., 2008. 230Th/U dating of interglacial and interstadial fen peat and lignite: potential and limits. Eiszeitalt. Ggw. 57, 77–94. Grün, Rainer, 2000. Methods of dose determination using ESR spectra of tooth enamel. Radiat. Meas. 32, 767–772. Grün, R., Katzenberger-Apel, O., 1994. An alpha irradiator for ESR dating. Ancient TL 12, 35–38. Grün, R., Schwarcz, H.P., Chadam, J.M., 1988. ESR dating of tooth enamel: coupled correction for U-uptake and U-series disequilibrium. Nucl. Tracks Radiat. Meas. 14, 237–241. Guérin, Gu, Mercier, N., Adamiec, G., 2011. Dose-rate conversion factors: update. Ancient TL 29, 5–8. Guérin, Gi, Antoine, P., Schmidt, E., Goval, E., Herisson, D., Jamet, G., Reyss, J.-L., Shao, Q., Philippe, A., Vibet, M.-A., Bahain, J.-J., 2017. Chronology of the Upper Pleistocene loess sequence of Havrincourt (France) and associated Palaeolithic occupations: a Bayesian approach from pedostratigraphy, OSL, radiocarbon TL and ESR/U-series data. Quat. Geochronol. 42, 15–30. Hérisson, D., 2016. Rapport de fouille programmée Waziers “Le Bas Terroir”. dir, p. 169 (p, unpublished manuscript). Limondin-Lozouet, N., 2011. Successions malacologiques à la charnière Glaciaire/ Interglaciaire : du modèle Tardiglaciaire-Holocène aux transitions du Pléistocène. Quaternaire 22, 211–220. Limondin-Lozouet, N., Preece, R.C., 2014. Quaternary perspectives on the diversity of land snail assemblages from NW Europe. J. Molluscan Stud. 80, 224–237. Lisiecki, L.E., Raymo, M.E., 2005. A Pliocene-Pleistocene stack of 57 globally distributed benthic d18O records. Paleoceanography 20, 1003. https://doi.org/10.1029/ 2004PA001071. Locht, J.L., Goval, E., Antoine, P., Coutard, S., Auguste, P., Paris, C., Hérisson, D., 2014. Palaeoenvironments and prehistoric interactions in northern France from the Eemian interglacial to the end of the Weichselian middle Pleniglacial. In: Foulds, F. W.F., Drinlall, H.C., Perri, A.R., Glinnick, D.T.G., Walker, J.W.P. (Eds.), Where Wild Things Are. Recent Advances in Palaeolithic and Mesolithic Research. Oxbow Press, Durham, pp. 70–78. Locht, J.L., Hérisson, D., Goval, E., Cliquet, D., Huet, B., Coutard, S., Antoine, P., Feray, P., 2016. Timescales, Space and Culture during the Middle Palaeolithic in Northwestern France Quaternary International, vol. 411, pp. 129–148. Ludwig, K.R., 2003. Isoplot 3.0, a Geochronological Toolkit for Microsoft Excel, vol. 4. Berkeley Geochronology Center Special Publication, p. 71p. Mercier, N., Falguères, C., 2007. Field gamma dose-rate measurement with a NaI(Tl) detector: re-evaluation of the "threshold" technique. Ancient TL 25, 1–4. 8