FOURCADE T., 2022 - Changements culturels et adaptations aux changements climatiques et environnementaux des derniers Néandertaliens dans le sud de la France. Thèse de Doctorat, Université Bordeaux Montaigne, Pessac, 427 p.
Cultural changes and adaptations to climatic and environmental changes of the last Neanderthals in southern France
Notes de l’auteur
Thèse co-dirigée par Christelle Lahaye et María Fernanda Sánchez-Goñi, disponible en ligne à l’adresse suivante : https://hal.science/tel-03924503v1
Texte intégral
1 - Introduction
1The role of climate change as a driver of biological and cultural human evolution is a recurrent topic in the scientific literature. In order to know whether a climatic or environmental change may have produced a cultural change, it is firstly necessary to test whether both are synchronous. Previous studies focussing on this question show the difficulty of comparing archaeological and palaeoenvironmental records from a chronological point of view, and this for three reasons: 1) the different temporal resolution of environmental and archaeological records, 2) the inherent uncertainties in dating methods, and 3) the definitions of the cultures used in these studies are often questioned.
2My thesis research has focused on testing the potential synchrony between cultural and climatic changes that punctuated the last glacial period (ca 115 – 27 kiloyears ago, ka), and particularly the possible role of climate changes as driver of the cultural changes of hunter-gatherers who occupied Western Europe between ~70 to 36 ka. This period corresponds to the end of the Middle Palaeolithic and the beginning of the Upper Palaeolithic (ca. 50-35 ka), marked by the disappearance of Neanderthals and the arrival of the Anatomically Modern Humans (AMH). This period was also marked by 12 millennial to centennial warming and cooling events in Greenland, called Dansgaard-Oeschger (D-O) 8 to 19 cycles, resulting in a succession of climate phases called Greenland Interstadial (GI, warm) and Greenland Stadial (GS, cold), the latter associated with North Atlantic cooling events. 3 large North American iceberg discharges, called Heinrich events (HE) occurred during particular GS, resulting in a climatic phase called Heinrich Stadial (HS 4 to 6). Deep-sea and terrestrial pollen records and speleothem archives from Western Europe and its margin show that D-O cycles and HEs have strongly affected European ecosystems and, in particular, those of Western France.
2 - Methods
3To test the synchrony between cultural transitions and environmental and climatic changes, I used a combined approach involving: a) the pollen analysis of 192 new samples from two deep-sea cores located in the Bay of Biscay and the Gulf of Lions (fig. 1), b) the luminescence dating of deep-sea cores, c) up-to-date Bayesian age models for the pollen and archaeological sequences, and d) the development of an archaeological database. Marine palynology allows the reconstruction of long and continuous regional environmental sequences. The comparison between pollen and other marine proxies, some of which are suitable for dating, provides good chronologies for terrestrial and marine palaeoenvironmental and climatic changes. Luminescence dating avoids the problem of C reservoir and age calibration and can date older periods than 45 ka.
Fig. 1: Localisation of the two studied deep-sea cores. Oceanic currents and winds are also represented. Fig. 1 : Localisation des deux carottes sédimentaires marines. Les courants océaniques et les vents sont aussi représentés.
4Pollen analysis were carried out at EPOC laboratory (Univ. of Bordeaux) on two deep-sea cores. A higher resolution pollen study (300 - 400 years) was performed on the Bay of Biscay one (MD04-2845, 45°21'N, 5°13'W) and a new study (800 - 1,000 years) was carried out on the Gulf of Lion one (MD99-2343, 40°29'N, 4°01'E) to reconstruct vegetation and climatic changes in southwestern and southeastern France during D-Os cycles and HSs (fig. 2).
Fig. 2: Synthetic figure of the results in this work. Fig. 2 : Figure synthétique des résultats de cette étude.
A) the curves of the astronomical parameters at 45°N, B) and C) the pollen percentages of the Atlantic/temperate forests and the steppes of the MD04-2845 and MD99-2343 cores and, D) the 68 % credibility intervals of the different archaeological cultures/lithic techno-complex (TCL) obtained by the Bayesian chronological modelling in the two regions. HSs are represented by blue rectangles, while D-O warmings are numerated.
A) Courbes des paramètres astronomiques à 45°N, B) et C) pourcentages polliniques des forêts Atlantique/tempérée et des steppes, issus des carottes marines MD04-2845 et MD99-2343 et, D) les intervalles de crédibilités à 68 % des différentes cultures/techno-complexes lithiques (TCL) archéologiques obtenus par la modélisation chronologique bayésienne. Les stadiaires d’Heinrich (HSs) sont représentés par les rectangles bleus et les réchauffements de D-O sont numérotés.
5One luminescence dating technique (i.e. IRSL on K-feldspars) was applied on the MD04-2845 deep-sea core, in order to improve the previous chronology, in increasing the age numbers between 30 and 140 ka. Thirteen samples were collected between 9 and 24 meters under controlled lighting and sampling conditions. Silt-sized grains (20 - 60 μm) and coarse-sized grains (100 - 140 μm) were extracted using standard procedures for measurements. The IRSL measurements, carried out at Archéosciences Bordeaux laboratory (Univ. Bordeaux Montaigne), show that the IRSL ages are mostly consistent with the stratigraphy and with 14C ages in the upper part of the core.
6We have also refined the previous chronologies by developing a new type of age-depth model using Bayesian statistics and stratigraphic orders between the dated depth by 14C, IRSL (the latter only for the MD04-2845 core) or by isotopic events. The new age-depth models for both cores were obtained using the chronological software called ChronoModel® and ArchaeoPhases® R-package. The new age-depth models were applied to the pollen records of both deep-sea cores to identify the vegetation responses to orbital and millennial climate changes.
7In order to test the synchrony of climate changes with cultural changes of Neanderthals and AMH in Western Europe, chronologies of the latter needed to be updated. The construction of cultural chronologies for both southwestern and southeastern France was based on archaeological databases, using a selection of ages according to their methodological or geoarchaeological reliabilities (e.g. samples without contamination, stratigraphy without taphonomic processes…). The ages have been integrated in ChronoModel® software and hierarchised according to the archaeological levels within the sites.
3 - Results
8The two new pollen records show in both regions, differences in environments, characterized mainly by forest expansions during D-O warmings and steppe developments during cooling (GS and HS). The magnitude of forest expansions during the D-O warmings 19 to 8 varies by latitude and would be related to different orbital configurations. HS 4 and 5 in both regions and HS 6 in southwestern France are characterized by steppic developments. In southeastern France, the steppe response to HS 4 and 5 seems to be modulated by local atmosphere-oceanic forcings in the Gulf of Lion, associated with the instability of the Laurentide ice sheet. Furthermore, the new pollen record in the northwestern Mediterranean highlights that in contrast to a steppe expansion during HS 6 in the Atlantic margin regions, a forest development characterizes this event, modulated by orbital parameters.
9New chronologies of Neanderthal and early AMH cultural changes in France show chronological overlaps in both regions, especially between Middle Palaeolithic lithic techno-complexes. According to Bayesian chronological modelling, the last Neanderthal cultures would not last beyond HS 4, dated in both cores between 40.0 and 38.2 ka. The first culture of the AMH, the Proto-Aurignacian, would be attested from 43 ka in southeastern, then from 42 ka in southwestern France and suggest that the AMH arrived in Western Europe around the D-O 11 warming. This would also suggest, from a chronological point of view, the possibility of a contact of at most 2 ka between Neanderthals and AMH in these two regions.
10The identification of potential synchronies remains difficult to perceive, due to the uncertainties associated with the different chronologies compared. Nevertheless, this thesis suggests that the progressive forest contraction, since the D-O 12 (ca 47 ka) favoured the arrival of AMH in Western Europe, leading perhaps to competition with Neanderthals for the same ecological niches and producing the disappearance of the latter.
11This work contributes to better understand the possible relationship between climate, environmental changes and regional human evolution. However, to improve our knowledge on the processes underlying human adaptations to climate changes, we need to quantify the spatial forest cover/steppe changes, and use process-based models such as the eco-cultural niche modelling approach. Moreover, there is also a need to reduce chronological uncertainties to better evaluate the potential synchronies between cultural and climate changes from the end of the Middle Palaeolithic to the beginning of the Upper Palaeolithic.
Table des illustrations
Titre | Fig. 1: Localisation of the two studied deep-sea cores. Oceanic currents and winds are also represented. Fig. 1 : Localisation des deux carottes sédimentaires marines. Les courants océaniques et les vents sont aussi représentés. |
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URL | http://journals.openedition.org/quaternaire/docannexe/image/17800/img-1.jpg |
Fichier | image/jpeg, 362k |
Titre | Fig. 2: Synthetic figure of the results in this work. Fig. 2 : Figure synthétique des résultats de cette étude. |
Légende | A) the curves of the astronomical parameters at 45°N, B) and C) the pollen percentages of the Atlantic/temperate forests and the steppes of the MD04-2845 and MD99-2343 cores and, D) the 68 % credibility intervals of the different archaeological cultures/lithic techno-complex (TCL) obtained by the Bayesian chronological modelling in the two regions. HSs are represented by blue rectangles, while D-O warmings are numerated.A) Courbes des paramètres astronomiques à 45°N, B) et C) pourcentages polliniques des forêts Atlantique/tempérée et des steppes, issus des carottes marines MD04-2845 et MD99-2343 et, D) les intervalles de crédibilités à 68 % des différentes cultures/techno-complexes lithiques (TCL) archéologiques obtenus par la modélisation chronologique bayésienne. Les stadiaires d’Heinrich (HSs) sont représentés par les rectangles bleus et les réchauffements de D-O sont numérotés. |
URL | http://journals.openedition.org/quaternaire/docannexe/image/17800/img-2.jpg |
Fichier | image/jpeg, 328k |
Pour citer cet article
Référence papier
Tiffanie Fourcade, « Cultural changes and adaptations to climatic and environmental changes of the last Neanderthals in southern France », Quaternaire, vol. 34/2 | 2023, 139-142.
Référence électronique
Tiffanie Fourcade, « Cultural changes and adaptations to climatic and environmental changes of the last Neanderthals in southern France », Quaternaire [En ligne], vol. 34/2 | 2023, mis en ligne le 10 juillet 2023, consulté le 31 octobre 2024. URL : http://journals.openedition.org/quaternaire/17800 ; DOI : https://doi.org/10.4000/quaternaire.17800
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