Within the framework of the studies focusing on the Pleistocene peopling of the Americas, our Fre... more Within the framework of the studies focusing on the Pleistocene peopling of the Americas, our French-Brazilian team has undertaken a pluridisciplinary research on different archaeological sites, inside and in the neighborhood of the Serra da Capivara National Park, in Brazilian Nordeste. The present study regards an archaeological site, Vale da Pedra Furada, situated in the Piauí state in Brazil. The results of technological and functional studies suggest the existence of different successive human occupations during the Pleistocene in this region. Moreover, the geological and geomorphological studies shed new light on our understanding of sedimentary processes and confirm that the levels were not subject to any significant post-depositional processes. This is also confirmed by macro-and micro-analysis of quartz artefact surfaces. The chronological study has recently been completed employing both radiocarbon and lumi-nescence techniques; radiocarbon dates were obtained on charcoal, multi-grain and single-grain OSL ages on sedimentary quartz grains. The results obtained with the different methods are consistent with each other: the most recent archaeological level is dated to around 8 ka and the oldest to 24 ka, indicating the open-air site of Vale da Pedra Furada to be a succession of human occupations beginning from OIS 2. These results are discussed in the context of some archaeological sites studied in the Serra da Capivara National Park of the last few decades.
The Acheulean is the longest lasting cultural–technological tradition in human evolutionary histo... more The Acheulean is the longest lasting cultural–technological tradition in human evolutionary history. However, considerable gaps remain in understanding the chronology and geographical distribution of Acheulean hominins. We present the first chronometrically dated Acheulean site from the Arabian Peninsula, a vast and poorly known region that forms more than half of Southwest Asia. Results show that Acheulean hominin occupation expanded along hydrological networks into the heart of Arabia from Marine Isotope Stage (MIS) 7 until at least ~190 ka ̶ the youngest documented Acheulean in Southwest Asia. The site of Saffaqah features Acheulean technology, characterized by large flakes, handaxes and cleavers, similar to Acheulean assemblages in Africa. These findings reveal a climatically mediated later Acheulean expansion into a poorly known region, amplifying the documented diversity of Middle Pleistocene hominin behaviour across the Old World and elaborating the terminal archaic landscape encountered by our species as they dispersed out of Africa.
Cet article présente une synthèse des données chronologiques du site des Pradelles (Marillac-le-F... more Cet article présente une synthèse des données chronologiques du site des Pradelles (Marillac-le-Franc, Charente, France). Le gisement se caractérise dans son locus est par un remplissage de près de quatre mètres d'épaisseur ayant livré des dépôts de la fin du Paléolithique moyen dans lesquels une industrie moustérienne de type Quina est associée à une faune abondante largement dominée par le renne. Durant les fouilles conduites par B. Maureille et A. Mann entre 2001 et 2013, les données chronologiques obtenues pour ce locus ont été peu nombreuses : une datation par thermoluminescence (TL) sur un silex chauffé et une autre par U-Th sur un spéléothème situé dans la partie inférieure de la séquence. Plusieurs datations par le radiocarbone ont été également réalisées sur des ossements provenant du sommet du remplissage, mais se sont révélées partiellement infructueuses en raison de l'ancienneté des vestiges. Ces données constituent des jalons importants permettant d'esquisser une chronologie préliminaire de cette séquence, sans toutefois donner une attribution chronologique précise aux vestiges découverts. Dans le cadre d'un projet pluridisciplinaire visant à établir des jalons chronologiques fiables pour l'évolution des cultures néandertaliennes du Sud-Ouest de la France, nous avons entrepris la datation des dépôts sédimentaires de la séquence
The Cueva del Angel (Lucena, Spain) is an open-air archaeological site with a sedimentary sequenc... more The Cueva del Angel (Lucena, Spain) is an open-air archaeological site with a sedimentary sequence remnant of a collapsed rock shelter which was part of a still active karst complex. The lithic assemblage consists essentially of abundant retouched tools including 46 identified handaxes along with non-modified flakes, and is associated with faunal remains dominated by Equus ferus and other large bovids and cervids. A large proportion of bones has undergone intense anthropic actions and been subjected to intense fire, thus evidencing sustained use of animal meat resources by humans.
In order to better ascertain the chronological framework of the site, we dated several proxies. Various speleothem samples were processed by U-series using a coupled induced plasma mass spectrometer (ICPMS-MC). The resulting isotopic ratios are beyond the secular equilibrium and show that these samples do not appear to be in direct stratigraphic relation with the archaeological sequence.
Nine Equus teeth were analyzed by the combined ESR/U-series method. These samples were taken from Unit I to Unit XVI representing at least 2.5 m of stratigraphic depth and approximately 90% of the infilling. Many of the dated samples are burnt given that more than 85% of the faunal remains exhibit traces of fire exposure.
The bone retouchers, for which a comparative analysis with other sites has been published (Moigne et al., 2016), were probably produced during the Marine Isotope Stage (MIS 11-5) chronological interval corresponding to the later part of the Middle Pleistocene, inference that is in agreement with the palaeontological assemblage of the site. The radiometric results presented here are consistent and indicate a range from 350 to 183 ka, suggesting that a major part of the sedimentary infilling coinciding with the human occupation was contemporaneous with the MIS 9 to 7 time period.
The late Pleistocene expansion of anatomically modern humans (AMHs) into Eurasia and the concurre... more The late Pleistocene expansion of anatomically modern humans (AMHs) into Eurasia and the concurrent demise of the Neanderthals appears to be a complex and regionally variable process. The southern Caucasus region, with its rich cave-sites, has recently provided important results regarding this process. In this paper we report on the results of fieldwork in Bondi Cave, Western Georgia, providing a new radiocarbon chronology, stratigraphic observations, analyses of lithic technology and provenance, faunal and floral remains as well as paleoenvironmental data. The cave includes Middle Palaeolithic (ca, 45,000 ka cal. BP) cultural horizons and a long Upper Palaeolithic sequence (ca. 40,000–27,000 cal. BP from layer V to IV). A modern human tooth was found in layer Vb. We estimate its age at 39,000–35,800 Cal BP (95.4%), based on the Bayesian age model we built. If the context of the tooth is reliable, as we think it is, this would make it the oldest morphologically modern human in the Caucasus. Upper Palaeolithic hunting of tur and bison, as well as the collection of various plants including flax is attested. Mobile Upper Palaeolithic foragers inhabited the cave in generally cold and dry periods, but a mosaic of environments, including forests and meadows, was nonetheless available to them. The archaeological sequence of Bondi and adjacent sites indicates a substantial time gap between the Middle and Upper Palaeolithic occupations, thus disproving Neanderthal-AMH interaction in this area and lending support to a replacement scenario in the southern Caucasus, assuming of course that the Early Upper Palaeolithic (EUP) is related to the arrival of AMHs.
Identifying systematic errors that are introduced by the measurement equipment is a necessary pre... more Identifying systematic errors that are introduced by the measurement equipment is a necessary prerequisite for reproducible measurements and reliable results. However, technical artefacts often remain unpublished. Here we report on a sudden change of lumi-nescence intensity observed while measuring IR-RF signals from K-feldspar extracts. The measurements were carried out on a lexsyg research reader. A lateral movement of the sample carrier up to 0.5 mm relative to the pho-tomultiplier tube and the irradiation source, causes a change in the sample geometry. This movement results in inter-aliquot scatter during the measurement of IR-RF. Two solutions are discussed to remove this effect: (I) data post-processing and (II) design change by the manufacturer. Our study so far is limited to IR-RF measurements on a single luminescence reader and suggests due caution in the identification of such systematic errors.
The site of La Quina Amont, located in the Charente region, is one of the most important sites in... more The site of La Quina Amont, located in the Charente region, is one of the most important sites in southwestern France for studying major changes in human behaviors from the Middle Paleolithic (MP) to the Early Upper Paleolithic (EUP). Extensively excavated over the past 50 years, numerous dating studies have been focused on the Upper Paleolithic deposits using radiocarbon on bone collagen and thermoluminescence (TL) on heated flints; however, the Mousterian levels remain undated due to the scarcity of suitable materials. Our investigations aimed to provide for the first time a chronological framework for the site using luminescence dating methods on different minerals contained in the sediments. Coarse grains of quartz were dated using the optically stimulated luminescence (OSL) technique, and poly-mineral fine grains were dated using both infrared (IRSL) and post-infrared (pIR-IRSL) stimulated luminescence signals. OSL, IRSL and pIR-IRSL results were combined with available TL and radiocarbon data sets to propose a chronology for the site. The agreement between these methods provides key insights into the sedimentological processes involved in the site formation and into the chronology of the human occupations. In particular, it shows that the sequence spans almost ~20,000 years (20 ka). Moreover, the new chronological framework suggests that the makers of the Quina lithic technocomplex (LTC), who were reindeer hunters, inhabited the site from the end of marine isotope stage (MIS) 4 to the beginning of MIS 3. We also show that Levallois and Discoidal industries occurred successively under temperate paleoclimatic conditions, during MIS 3 but not after ~40 ka. Finally, we compare the Quina LTC dataset with other sites in southern France in order to shed light upon the variability in Mousterian industries of this region.
In this study we compare different infrared stimulated luminescence (IRSL) signals for dating arc... more In this study we compare different infrared stimulated luminescence (IRSL) signals for dating archaeological deposits. The IRSL and the more recently developed post-IR IRSL (pIR-IR) methods were investigated using polymineral fine grains extracted from the Middle and Upper Palaeolithic western excavation area in the site of La Ferrassie (SW France). The IRSL data measured at 50 °C (IR50) are compared to those obtained with the elevated pIR-IR signals measured for two stimulation temperatures, 225 °C (pIR-IR225) and 290 °C (pIR-IR290). The signals are documented in terms of bleaching and fading rates. In addition, comparisons of the IR50 ages corrected either with the H + L method (Huntley and Lamothe, 2001) or with the dose rate correction method (DRC, Lamothe et al., 2003) are presented. Results show that the polymineral fine grains give a reasonable estimate of the burial age of the samples. The IR50 and pIR-IR225 provide the most reliable ages when they are corrected using the DRC method (because of saturation effects). The polymineral ages are then compared with the previously obtained ages of K-feldspars coarse grains, quartz OSL (Guerin et al., 2015) and radiocarbon ages with the aim of accessing information on the depositional processes. It appears that further comparison of polymineral fine grains to coarse grains is beneficial to evaluate bleaching. Moreover, the polymineral results either confirm or refine the chronology of the La Ferrassie sequence proposed by Guérin et al. (2015), that is, the Mousterian layers range from marine isotope stage (MIS) 5 to the middle of MIS 3. In particular, i) the base of Layer 3 is pushed back to the end of MIS 4 or beginning MIS 3 and ii) the chronological attribution of Layers 4 and 5 is confirmed as MIS 3. Finally, the chronology of the Aurignacian layer (Layer 7) is strengthened by all the feldspars results.
Measuring the infrared radiofluorescence (IR-RF) signal of K-feldspars, which is thought to be no... more Measuring the infrared radiofluorescence (IR-RF) signal of K-feldspars, which is thought to be not affected by any anomalous fading, potentially provides a promising alternative dating approach to the more studied IR and pIRIR signals. Here we report a series of experiments aimed at characterising the IR-RF signal, which led us to propose an improved IR-SAR (Infrared Radiofluorescence Single-Aliquot Regeneration) protocol. In comparison with the original protocol from Erfurt and Krbetschek (2003a), the proposed one relies on IR-RF signal measurements and bleaching experiments conducted at elevated temperatures. Stabilising the temperature at 70 °C during the measurements helps keeping the very shallow traps empty during the process. Internal protocol tests and dating applications are presented using known age samples. We show that the improved protocol (named RF70) is capable to reproduce known age results within uncertainties. However, considering the slow bleaching rate of the RF70 signal, the multi-grain approach is likely not the most suitable for the De determination of complex samples.
The late Pleistocene expansion of anatomically modern humans (AMHs) into Eurasia and the concurre... more The late Pleistocene expansion of anatomically modern humans (AMHs) into Eurasia and the concurrent demise of the Neanderthals appears to be a complex and regionally variable process. The southern Caucasus region, with its rich cave-sites, has recently provided important results regarding this process. In this paper we report on the results of fieldwork in Bondi Cave, Western Georgia, providing a new radiocarbon chronology, stratigraphic observations, analyses of lithic technology and provenance, faunal and floral remains as well as paleoenvironmental data. The cave includes Middle Palaeolithic (ca, 45,000 ka cal. BP) cultural horizons and a long Upper Palaeolithic sequence (ca. 40,000e27,000 cal. BP from layer V to IV). A modern human tooth was found in layer Vb. We estimate its age at 39,000 e35,800 Cal BP (95.4%), based on the Bayesian age model we built. If the context of the tooth is reliable, as we think it is, this would make it the oldest morphologically modern human in the Caucasus. Upper Palaeolithic hunting of tur and bison, as well as the collection of various plants including flax is attested. Mobile Upper Palaeolithic foragers inhabited the cave in generally cold and dry periods, but a mosaic of environments, including forests and meadows, was nonetheless available to them. The archaeological sequence of Bondi and adjacent sites indicates a substantial time gap between the Middle and Upper Palaeolithic occupations, thus disproving Neanderthal-AMH interaction in this area and lending support to a replacement scenario in the southern Caucasus, assuming of course that the Early Upper Palaeolithic (EUP) is related to the arrival of AMHs.
Located in southwest France, Roc de Marsal is a cave with a rich Mousterian stratigraphic sequenc... more Located in southwest France, Roc de Marsal is a cave with a rich Mousterian stratigraphic sequence. The lower part of the sequence (Layers 9e5) are characterized by assemblages dominated by Levallois lithic technology associated with composite faunal spectra (including red deer, roe deer and reindeer) that shows a gradual increase in the frequency of reindeer. The top of the sequence (Layers 4e2) are characterised instead by Quina lithic technology (both in terms of technology and typology) with the faunal remains dominated by reindeer. Roc de Marsal thus provides a very interesting case study to place behavioural changes in a context of changing climates and environments in western Europe during the late Pleistocene. To link the occupations at Roc de Marsal with global and regional climatic conditions known independently, a robust chronology is needed. With this aim in mind, we applied three luminescence dating methods (TL, OSL and IRSL) on different minerals (flint, quartz and K-feldspar extracts). Here the results of two of these methods are presented in detail (TL and OSL) and compared with preliminary IRSL data. At Roc de Marsal, a comparison of methods was necessary to overcome a complex sedimentary history, with very heterogeneous dose rate distributions, both at the beta (mm) and gamma (dm) dose rate scales. The results indicate that the lower Levallois layers are dated to ~65e70 ka, while overlying Quina layers are dated to ~49 ka. These ages for the lower layers fit well with some models that place mixed faunal assemblages in the initial MIS 4; however, while the Quina ages overlap with several other Quina assemblages from the region, they place the reindeer dominated fauna well after the peak cold of MIS 4 and suggest a more extended and complex period of contemporaneous lithic techno-complexes than posited by some current models.
Measuring the infrared radiofluorescence (IR-RF) signal is methodologically simpler than measurin... more Measuring the infrared radiofluorescence (IR-RF) signal is methodologically simpler than measuring the IRSL or TL signals. However, unlike classical luminescence measurements, the IR-RF signal is totally resetting when its highest value is reached. Previous studies (Buylaert et al., 2012; Trautmann et al., 2000) reported that the proper bleaching level of an IR-RF signal is difficult to define and seems to be dependent 1) on the wavelength used for bleaching and 2) on exposure duration. The IR-RF signals from K-feldspar samples have been measured with various bleaching wavelengths and exposure time using a Lexsyg research luminescence unit. In this study, we propose suitable bleaching parameters adapted to IR-RF measurements.
Infrared radiofluorescence of K-feldspar was measured. A TL-like peak shape is noticeable, after ... more Infrared radiofluorescence of K-feldspar was measured. A TL-like peak shape is noticeable, after bleaching. We demonstrate the presence of a shallow TL trap, responsible for the odd peak.
Within the framework of the studies focusing on the Pleistocene peopling of the Americas, our Fre... more Within the framework of the studies focusing on the Pleistocene peopling of the Americas, our French-Brazilian team has undertaken a pluridisciplinary research on different archaeological sites, inside and in the neighborhood of the Serra da Capivara National Park, in Brazilian Nordeste. The present study regards an archaeological site, Vale da Pedra Furada, situated in the Piauí state in Brazil. The results of technological and functional studies suggest the existence of different successive human occupations during the Pleistocene in this region. Moreover, the geological and geomorphological studies shed new light on our understanding of sedimentary processes and confirm that the levels were not subject to any significant post-depositional processes. This is also confirmed by macro- and micro-analysis of quartz artefact surfaces. The chronological study has recently been completed employing both radiocarbon and luminescence techniques; radiocarbon dates were obtained on charcoal, multi-grain and single-grain OSL ages on sedimentary quartz grains. The results obtained with the different methods are consistent with each other: the most recent archaeological level is dated to around 8 ka and the oldest to 24 ka, indicating the open-air site of Vale da Pedra Furada to be a succession of human occupations beginning from OIS 2. These results are discussed in the context of some archaeological sites studied in the Serra da Capivara National Park of the last few decades.
A new interdisciplinary project was initiated to excavate a portion of the Palaeolithic site of L... more A new interdisciplinary project was initiated to excavate a portion of the Palaeolithic site of La Ferrassie left intact by earlier excavations. One of the aims of this project was to provide chronological information on the succession of Middle and Upper Palaeolithic layers, as well as on the skeletons unearthed by Capitan and Peyrony in the early 1900's. We report here preliminary results on the lithics, faunal remains, site formation processes, and on the stratigraphic context of the La Ferrassie 1 and 2 skeletons that were found adjacent to our excavations. Finally, results from luminescence dating of the sediments and a preliminary set of radiocarbon ages are presented. Quartz OSL, both at the multi-grain and single-grain levels of analysis, and post-IR IRSL of feldspar at various stimulation temperatures are compared. The quartz/feldspar comparison revealed a bleaching problem for the quartz OSL (and the feldspar pIRIR signals) from Layer 2; as a consequence, the age of this Layer was determined using a minimum age model.
"The Shi’bat Dihya 1 site in western Yemen, dated by optically stimulated luminescence
to 55 ka,... more "The Shi’bat Dihya 1 site in western Yemen, dated by optically stimulated luminescence
to 55 ka, provides insight into the Middle Paleolithic peopling of
the Arabian Peninsula. The archaeological layer is interstratified within thick,
sandy silt floodplain deposits filling a piedmont basin. Luminescence dates, lack
of soil development, and gypsum precipitation indicate a high accretion rate of
the floodplain during Marine Isotope Stage 3, in connection with a (semi)-arid
environment. Rapid overbank sedimentation was likely a result of the remobilization
of loess material deposited on the Yemeni Great Escarpment at the
periphery of the adjacent Tihama coastal sand desert or of other sources. Fabric
and size analyses of the lithic artifacts, together with spatial projections, indicate
site modifications by floods. Primary modifications include (1) selective
accumulation of medium-sized lithic pieces as a result of hydraulic sorting, (2)
bimodal orientation of artifacts, and (3) ripple-like arrangement of lithics and
bone/tooth fragments. The overrepresentation of teeth may also be a consequence
of sorting. Although floods have distorted the original site patterning,
long-distance transport of artifacts by water can be excluded, as indicated by
relatively high refitting rate, close proximity of artifacts derived from the same
block of raw material, and lack of abrasion of the pieces. Therefore, the site is
considered “geologically” in situ because its remobilization by water occurred
shortly after human abandonment. This study also stresses that the effective
preservation of a site cannot be assessed without careful taphonomic study,
even in a potentially favorable depositional context such as silty alluvium."
The lower terraces of the Dordogne River at Bergerac (south-west France) were studied in detail u... more The lower terraces of the Dordogne River at Bergerac (south-west France) were studied in detail using cores, trenches, ground penetrating radar profiles, and 14 C, optically stimulated luminescence and infrared stimulated luminescence dating. This study shows that the lowest terrace (Fx) is made up of two major lithostratigraphic units: (i) dominantly horizontal gravel strata interpreted as compound bar deposits in a braided river, which pre-date 18-17 ka, and (ii) thick lateral accretion gravel units (point bars) formed in an anabranching river during the Late Pleniglacial and Lateglacial. Most of the anabranching channels were abandoned at ca. 11-10 ka following shrinkage of the river bed into a single meandering channel and were partially filled by gyttjas during the Boreal chronozone. Finally, the channels were plugged by overbank fines until about 5 ka. Floods seldom reached the Fx terrace during the late Holocene and accretion became negligible. The main phase of bedrock incision spanned the Holocene, whereas the period of channel adjustment to change in river regime during late Marine Isotope Stage (MIS) 2 only led to a redistribution of the Pleniglacial gravels. The higher terrace (Fw3) formed before the Eemian and was covered by colluvial fans, mainly during MIS 2 and 3.
Within the framework of the studies focusing on the Pleistocene peopling of the Americas, our Fre... more Within the framework of the studies focusing on the Pleistocene peopling of the Americas, our French-Brazilian team has undertaken a pluridisciplinary research on different archaeological sites, inside and in the neighborhood of the Serra da Capivara National Park, in Brazilian Nordeste. The present study regards an archaeological site, Vale da Pedra Furada, situated in the Piauí state in Brazil. The results of technological and functional studies suggest the existence of different successive human occupations during the Pleistocene in this region. Moreover, the geological and geomorphological studies shed new light on our understanding of sedimentary processes and confirm that the levels were not subject to any significant post-depositional processes. This is also confirmed by macro-and micro-analysis of quartz artefact surfaces. The chronological study has recently been completed employing both radiocarbon and lumi-nescence techniques; radiocarbon dates were obtained on charcoal, multi-grain and single-grain OSL ages on sedimentary quartz grains. The results obtained with the different methods are consistent with each other: the most recent archaeological level is dated to around 8 ka and the oldest to 24 ka, indicating the open-air site of Vale da Pedra Furada to be a succession of human occupations beginning from OIS 2. These results are discussed in the context of some archaeological sites studied in the Serra da Capivara National Park of the last few decades.
The Acheulean is the longest lasting cultural–technological tradition in human evolutionary histo... more The Acheulean is the longest lasting cultural–technological tradition in human evolutionary history. However, considerable gaps remain in understanding the chronology and geographical distribution of Acheulean hominins. We present the first chronometrically dated Acheulean site from the Arabian Peninsula, a vast and poorly known region that forms more than half of Southwest Asia. Results show that Acheulean hominin occupation expanded along hydrological networks into the heart of Arabia from Marine Isotope Stage (MIS) 7 until at least ~190 ka ̶ the youngest documented Acheulean in Southwest Asia. The site of Saffaqah features Acheulean technology, characterized by large flakes, handaxes and cleavers, similar to Acheulean assemblages in Africa. These findings reveal a climatically mediated later Acheulean expansion into a poorly known region, amplifying the documented diversity of Middle Pleistocene hominin behaviour across the Old World and elaborating the terminal archaic landscape encountered by our species as they dispersed out of Africa.
Cet article présente une synthèse des données chronologiques du site des Pradelles (Marillac-le-F... more Cet article présente une synthèse des données chronologiques du site des Pradelles (Marillac-le-Franc, Charente, France). Le gisement se caractérise dans son locus est par un remplissage de près de quatre mètres d'épaisseur ayant livré des dépôts de la fin du Paléolithique moyen dans lesquels une industrie moustérienne de type Quina est associée à une faune abondante largement dominée par le renne. Durant les fouilles conduites par B. Maureille et A. Mann entre 2001 et 2013, les données chronologiques obtenues pour ce locus ont été peu nombreuses : une datation par thermoluminescence (TL) sur un silex chauffé et une autre par U-Th sur un spéléothème situé dans la partie inférieure de la séquence. Plusieurs datations par le radiocarbone ont été également réalisées sur des ossements provenant du sommet du remplissage, mais se sont révélées partiellement infructueuses en raison de l'ancienneté des vestiges. Ces données constituent des jalons importants permettant d'esquisser une chronologie préliminaire de cette séquence, sans toutefois donner une attribution chronologique précise aux vestiges découverts. Dans le cadre d'un projet pluridisciplinaire visant à établir des jalons chronologiques fiables pour l'évolution des cultures néandertaliennes du Sud-Ouest de la France, nous avons entrepris la datation des dépôts sédimentaires de la séquence
The Cueva del Angel (Lucena, Spain) is an open-air archaeological site with a sedimentary sequenc... more The Cueva del Angel (Lucena, Spain) is an open-air archaeological site with a sedimentary sequence remnant of a collapsed rock shelter which was part of a still active karst complex. The lithic assemblage consists essentially of abundant retouched tools including 46 identified handaxes along with non-modified flakes, and is associated with faunal remains dominated by Equus ferus and other large bovids and cervids. A large proportion of bones has undergone intense anthropic actions and been subjected to intense fire, thus evidencing sustained use of animal meat resources by humans.
In order to better ascertain the chronological framework of the site, we dated several proxies. Various speleothem samples were processed by U-series using a coupled induced plasma mass spectrometer (ICPMS-MC). The resulting isotopic ratios are beyond the secular equilibrium and show that these samples do not appear to be in direct stratigraphic relation with the archaeological sequence.
Nine Equus teeth were analyzed by the combined ESR/U-series method. These samples were taken from Unit I to Unit XVI representing at least 2.5 m of stratigraphic depth and approximately 90% of the infilling. Many of the dated samples are burnt given that more than 85% of the faunal remains exhibit traces of fire exposure.
The bone retouchers, for which a comparative analysis with other sites has been published (Moigne et al., 2016), were probably produced during the Marine Isotope Stage (MIS 11-5) chronological interval corresponding to the later part of the Middle Pleistocene, inference that is in agreement with the palaeontological assemblage of the site. The radiometric results presented here are consistent and indicate a range from 350 to 183 ka, suggesting that a major part of the sedimentary infilling coinciding with the human occupation was contemporaneous with the MIS 9 to 7 time period.
The late Pleistocene expansion of anatomically modern humans (AMHs) into Eurasia and the concurre... more The late Pleistocene expansion of anatomically modern humans (AMHs) into Eurasia and the concurrent demise of the Neanderthals appears to be a complex and regionally variable process. The southern Caucasus region, with its rich cave-sites, has recently provided important results regarding this process. In this paper we report on the results of fieldwork in Bondi Cave, Western Georgia, providing a new radiocarbon chronology, stratigraphic observations, analyses of lithic technology and provenance, faunal and floral remains as well as paleoenvironmental data. The cave includes Middle Palaeolithic (ca, 45,000 ka cal. BP) cultural horizons and a long Upper Palaeolithic sequence (ca. 40,000–27,000 cal. BP from layer V to IV). A modern human tooth was found in layer Vb. We estimate its age at 39,000–35,800 Cal BP (95.4%), based on the Bayesian age model we built. If the context of the tooth is reliable, as we think it is, this would make it the oldest morphologically modern human in the Caucasus. Upper Palaeolithic hunting of tur and bison, as well as the collection of various plants including flax is attested. Mobile Upper Palaeolithic foragers inhabited the cave in generally cold and dry periods, but a mosaic of environments, including forests and meadows, was nonetheless available to them. The archaeological sequence of Bondi and adjacent sites indicates a substantial time gap between the Middle and Upper Palaeolithic occupations, thus disproving Neanderthal-AMH interaction in this area and lending support to a replacement scenario in the southern Caucasus, assuming of course that the Early Upper Palaeolithic (EUP) is related to the arrival of AMHs.
Identifying systematic errors that are introduced by the measurement equipment is a necessary pre... more Identifying systematic errors that are introduced by the measurement equipment is a necessary prerequisite for reproducible measurements and reliable results. However, technical artefacts often remain unpublished. Here we report on a sudden change of lumi-nescence intensity observed while measuring IR-RF signals from K-feldspar extracts. The measurements were carried out on a lexsyg research reader. A lateral movement of the sample carrier up to 0.5 mm relative to the pho-tomultiplier tube and the irradiation source, causes a change in the sample geometry. This movement results in inter-aliquot scatter during the measurement of IR-RF. Two solutions are discussed to remove this effect: (I) data post-processing and (II) design change by the manufacturer. Our study so far is limited to IR-RF measurements on a single luminescence reader and suggests due caution in the identification of such systematic errors.
The site of La Quina Amont, located in the Charente region, is one of the most important sites in... more The site of La Quina Amont, located in the Charente region, is one of the most important sites in southwestern France for studying major changes in human behaviors from the Middle Paleolithic (MP) to the Early Upper Paleolithic (EUP). Extensively excavated over the past 50 years, numerous dating studies have been focused on the Upper Paleolithic deposits using radiocarbon on bone collagen and thermoluminescence (TL) on heated flints; however, the Mousterian levels remain undated due to the scarcity of suitable materials. Our investigations aimed to provide for the first time a chronological framework for the site using luminescence dating methods on different minerals contained in the sediments. Coarse grains of quartz were dated using the optically stimulated luminescence (OSL) technique, and poly-mineral fine grains were dated using both infrared (IRSL) and post-infrared (pIR-IRSL) stimulated luminescence signals. OSL, IRSL and pIR-IRSL results were combined with available TL and radiocarbon data sets to propose a chronology for the site. The agreement between these methods provides key insights into the sedimentological processes involved in the site formation and into the chronology of the human occupations. In particular, it shows that the sequence spans almost ~20,000 years (20 ka). Moreover, the new chronological framework suggests that the makers of the Quina lithic technocomplex (LTC), who were reindeer hunters, inhabited the site from the end of marine isotope stage (MIS) 4 to the beginning of MIS 3. We also show that Levallois and Discoidal industries occurred successively under temperate paleoclimatic conditions, during MIS 3 but not after ~40 ka. Finally, we compare the Quina LTC dataset with other sites in southern France in order to shed light upon the variability in Mousterian industries of this region.
In this study we compare different infrared stimulated luminescence (IRSL) signals for dating arc... more In this study we compare different infrared stimulated luminescence (IRSL) signals for dating archaeological deposits. The IRSL and the more recently developed post-IR IRSL (pIR-IR) methods were investigated using polymineral fine grains extracted from the Middle and Upper Palaeolithic western excavation area in the site of La Ferrassie (SW France). The IRSL data measured at 50 °C (IR50) are compared to those obtained with the elevated pIR-IR signals measured for two stimulation temperatures, 225 °C (pIR-IR225) and 290 °C (pIR-IR290). The signals are documented in terms of bleaching and fading rates. In addition, comparisons of the IR50 ages corrected either with the H + L method (Huntley and Lamothe, 2001) or with the dose rate correction method (DRC, Lamothe et al., 2003) are presented. Results show that the polymineral fine grains give a reasonable estimate of the burial age of the samples. The IR50 and pIR-IR225 provide the most reliable ages when they are corrected using the DRC method (because of saturation effects). The polymineral ages are then compared with the previously obtained ages of K-feldspars coarse grains, quartz OSL (Guerin et al., 2015) and radiocarbon ages with the aim of accessing information on the depositional processes. It appears that further comparison of polymineral fine grains to coarse grains is beneficial to evaluate bleaching. Moreover, the polymineral results either confirm or refine the chronology of the La Ferrassie sequence proposed by Guérin et al. (2015), that is, the Mousterian layers range from marine isotope stage (MIS) 5 to the middle of MIS 3. In particular, i) the base of Layer 3 is pushed back to the end of MIS 4 or beginning MIS 3 and ii) the chronological attribution of Layers 4 and 5 is confirmed as MIS 3. Finally, the chronology of the Aurignacian layer (Layer 7) is strengthened by all the feldspars results.
Measuring the infrared radiofluorescence (IR-RF) signal of K-feldspars, which is thought to be no... more Measuring the infrared radiofluorescence (IR-RF) signal of K-feldspars, which is thought to be not affected by any anomalous fading, potentially provides a promising alternative dating approach to the more studied IR and pIRIR signals. Here we report a series of experiments aimed at characterising the IR-RF signal, which led us to propose an improved IR-SAR (Infrared Radiofluorescence Single-Aliquot Regeneration) protocol. In comparison with the original protocol from Erfurt and Krbetschek (2003a), the proposed one relies on IR-RF signal measurements and bleaching experiments conducted at elevated temperatures. Stabilising the temperature at 70 °C during the measurements helps keeping the very shallow traps empty during the process. Internal protocol tests and dating applications are presented using known age samples. We show that the improved protocol (named RF70) is capable to reproduce known age results within uncertainties. However, considering the slow bleaching rate of the RF70 signal, the multi-grain approach is likely not the most suitable for the De determination of complex samples.
The late Pleistocene expansion of anatomically modern humans (AMHs) into Eurasia and the concurre... more The late Pleistocene expansion of anatomically modern humans (AMHs) into Eurasia and the concurrent demise of the Neanderthals appears to be a complex and regionally variable process. The southern Caucasus region, with its rich cave-sites, has recently provided important results regarding this process. In this paper we report on the results of fieldwork in Bondi Cave, Western Georgia, providing a new radiocarbon chronology, stratigraphic observations, analyses of lithic technology and provenance, faunal and floral remains as well as paleoenvironmental data. The cave includes Middle Palaeolithic (ca, 45,000 ka cal. BP) cultural horizons and a long Upper Palaeolithic sequence (ca. 40,000e27,000 cal. BP from layer V to IV). A modern human tooth was found in layer Vb. We estimate its age at 39,000 e35,800 Cal BP (95.4%), based on the Bayesian age model we built. If the context of the tooth is reliable, as we think it is, this would make it the oldest morphologically modern human in the Caucasus. Upper Palaeolithic hunting of tur and bison, as well as the collection of various plants including flax is attested. Mobile Upper Palaeolithic foragers inhabited the cave in generally cold and dry periods, but a mosaic of environments, including forests and meadows, was nonetheless available to them. The archaeological sequence of Bondi and adjacent sites indicates a substantial time gap between the Middle and Upper Palaeolithic occupations, thus disproving Neanderthal-AMH interaction in this area and lending support to a replacement scenario in the southern Caucasus, assuming of course that the Early Upper Palaeolithic (EUP) is related to the arrival of AMHs.
Located in southwest France, Roc de Marsal is a cave with a rich Mousterian stratigraphic sequenc... more Located in southwest France, Roc de Marsal is a cave with a rich Mousterian stratigraphic sequence. The lower part of the sequence (Layers 9e5) are characterized by assemblages dominated by Levallois lithic technology associated with composite faunal spectra (including red deer, roe deer and reindeer) that shows a gradual increase in the frequency of reindeer. The top of the sequence (Layers 4e2) are characterised instead by Quina lithic technology (both in terms of technology and typology) with the faunal remains dominated by reindeer. Roc de Marsal thus provides a very interesting case study to place behavioural changes in a context of changing climates and environments in western Europe during the late Pleistocene. To link the occupations at Roc de Marsal with global and regional climatic conditions known independently, a robust chronology is needed. With this aim in mind, we applied three luminescence dating methods (TL, OSL and IRSL) on different minerals (flint, quartz and K-feldspar extracts). Here the results of two of these methods are presented in detail (TL and OSL) and compared with preliminary IRSL data. At Roc de Marsal, a comparison of methods was necessary to overcome a complex sedimentary history, with very heterogeneous dose rate distributions, both at the beta (mm) and gamma (dm) dose rate scales. The results indicate that the lower Levallois layers are dated to ~65e70 ka, while overlying Quina layers are dated to ~49 ka. These ages for the lower layers fit well with some models that place mixed faunal assemblages in the initial MIS 4; however, while the Quina ages overlap with several other Quina assemblages from the region, they place the reindeer dominated fauna well after the peak cold of MIS 4 and suggest a more extended and complex period of contemporaneous lithic techno-complexes than posited by some current models.
Measuring the infrared radiofluorescence (IR-RF) signal is methodologically simpler than measurin... more Measuring the infrared radiofluorescence (IR-RF) signal is methodologically simpler than measuring the IRSL or TL signals. However, unlike classical luminescence measurements, the IR-RF signal is totally resetting when its highest value is reached. Previous studies (Buylaert et al., 2012; Trautmann et al., 2000) reported that the proper bleaching level of an IR-RF signal is difficult to define and seems to be dependent 1) on the wavelength used for bleaching and 2) on exposure duration. The IR-RF signals from K-feldspar samples have been measured with various bleaching wavelengths and exposure time using a Lexsyg research luminescence unit. In this study, we propose suitable bleaching parameters adapted to IR-RF measurements.
Infrared radiofluorescence of K-feldspar was measured. A TL-like peak shape is noticeable, after ... more Infrared radiofluorescence of K-feldspar was measured. A TL-like peak shape is noticeable, after bleaching. We demonstrate the presence of a shallow TL trap, responsible for the odd peak.
Within the framework of the studies focusing on the Pleistocene peopling of the Americas, our Fre... more Within the framework of the studies focusing on the Pleistocene peopling of the Americas, our French-Brazilian team has undertaken a pluridisciplinary research on different archaeological sites, inside and in the neighborhood of the Serra da Capivara National Park, in Brazilian Nordeste. The present study regards an archaeological site, Vale da Pedra Furada, situated in the Piauí state in Brazil. The results of technological and functional studies suggest the existence of different successive human occupations during the Pleistocene in this region. Moreover, the geological and geomorphological studies shed new light on our understanding of sedimentary processes and confirm that the levels were not subject to any significant post-depositional processes. This is also confirmed by macro- and micro-analysis of quartz artefact surfaces. The chronological study has recently been completed employing both radiocarbon and luminescence techniques; radiocarbon dates were obtained on charcoal, multi-grain and single-grain OSL ages on sedimentary quartz grains. The results obtained with the different methods are consistent with each other: the most recent archaeological level is dated to around 8 ka and the oldest to 24 ka, indicating the open-air site of Vale da Pedra Furada to be a succession of human occupations beginning from OIS 2. These results are discussed in the context of some archaeological sites studied in the Serra da Capivara National Park of the last few decades.
A new interdisciplinary project was initiated to excavate a portion of the Palaeolithic site of L... more A new interdisciplinary project was initiated to excavate a portion of the Palaeolithic site of La Ferrassie left intact by earlier excavations. One of the aims of this project was to provide chronological information on the succession of Middle and Upper Palaeolithic layers, as well as on the skeletons unearthed by Capitan and Peyrony in the early 1900's. We report here preliminary results on the lithics, faunal remains, site formation processes, and on the stratigraphic context of the La Ferrassie 1 and 2 skeletons that were found adjacent to our excavations. Finally, results from luminescence dating of the sediments and a preliminary set of radiocarbon ages are presented. Quartz OSL, both at the multi-grain and single-grain levels of analysis, and post-IR IRSL of feldspar at various stimulation temperatures are compared. The quartz/feldspar comparison revealed a bleaching problem for the quartz OSL (and the feldspar pIRIR signals) from Layer 2; as a consequence, the age of this Layer was determined using a minimum age model.
"The Shi’bat Dihya 1 site in western Yemen, dated by optically stimulated luminescence
to 55 ka,... more "The Shi’bat Dihya 1 site in western Yemen, dated by optically stimulated luminescence
to 55 ka, provides insight into the Middle Paleolithic peopling of
the Arabian Peninsula. The archaeological layer is interstratified within thick,
sandy silt floodplain deposits filling a piedmont basin. Luminescence dates, lack
of soil development, and gypsum precipitation indicate a high accretion rate of
the floodplain during Marine Isotope Stage 3, in connection with a (semi)-arid
environment. Rapid overbank sedimentation was likely a result of the remobilization
of loess material deposited on the Yemeni Great Escarpment at the
periphery of the adjacent Tihama coastal sand desert or of other sources. Fabric
and size analyses of the lithic artifacts, together with spatial projections, indicate
site modifications by floods. Primary modifications include (1) selective
accumulation of medium-sized lithic pieces as a result of hydraulic sorting, (2)
bimodal orientation of artifacts, and (3) ripple-like arrangement of lithics and
bone/tooth fragments. The overrepresentation of teeth may also be a consequence
of sorting. Although floods have distorted the original site patterning,
long-distance transport of artifacts by water can be excluded, as indicated by
relatively high refitting rate, close proximity of artifacts derived from the same
block of raw material, and lack of abrasion of the pieces. Therefore, the site is
considered “geologically” in situ because its remobilization by water occurred
shortly after human abandonment. This study also stresses that the effective
preservation of a site cannot be assessed without careful taphonomic study,
even in a potentially favorable depositional context such as silty alluvium."
The lower terraces of the Dordogne River at Bergerac (south-west France) were studied in detail u... more The lower terraces of the Dordogne River at Bergerac (south-west France) were studied in detail using cores, trenches, ground penetrating radar profiles, and 14 C, optically stimulated luminescence and infrared stimulated luminescence dating. This study shows that the lowest terrace (Fx) is made up of two major lithostratigraphic units: (i) dominantly horizontal gravel strata interpreted as compound bar deposits in a braided river, which pre-date 18-17 ka, and (ii) thick lateral accretion gravel units (point bars) formed in an anabranching river during the Late Pleniglacial and Lateglacial. Most of the anabranching channels were abandoned at ca. 11-10 ka following shrinkage of the river bed into a single meandering channel and were partially filled by gyttjas during the Boreal chronozone. Finally, the channels were plugged by overbank fines until about 5 ka. Floods seldom reached the Fx terrace during the late Holocene and accretion became negligible. The main phase of bedrock incision spanned the Holocene, whereas the period of channel adjustment to change in river regime during late Marine Isotope Stage (MIS) 2 only led to a redistribution of the Pleniglacial gravels. The higher terrace (Fw3) formed before the Eemian and was covered by colluvial fans, mainly during MIS 2 and 3.
Au cours des trente dernières années, la datation des feldspaths par luminescence stimulée optiqu... more Au cours des trente dernières années, la datation des feldspaths par luminescence stimulée optiquement s'est considérablement développée tant au niveau de ses applications géologiques et archéologiques qu'au niveau des méthodologies employées. Pour autant, la question du fading (c'està-dire la « perte de signal au cours du temps ») reste ouverte. D'abord focalisées sur des méthodes de correction du fading dans les feldspaths, les stratégies de recherches se sont progressivement portées sur des méthodes permettant la minimisation du fading, puis plus récemment encore sur son évitement. Cette dernière voie de recherche a été introduite pour la première fois en 1999, il s'agit de la datation par radiofluorescence par infrarouge (IR-RF). La méthode permet d'accéder directement à la densité de charges qui se sont accumulées dans les pièges électroniques au cours du temps sans faire intervenir les processus de libération et recombinaison qui interviennent en IRSL.
Au cours des trente dernières années, la datation des feldspaths par luminescence stimulée optiqu... more Au cours des trente dernières années, la datation des feldspaths par luminescence stimulée optiquement s'est considérablement développée tant au niveau de ses applications géologiques et archéologiques qu'au niveau des méthodologies employées. Pour autant, la question du fading (c'està-dire la « perte de signal au cours du temps ») reste ouverte. D'abord focalisées sur des méthodes de correction du fading dans les feldspaths, les stratégies de recherches se sont progressivement portées sur des méthodes permettant la minimisation du fading, puis plus récemment encore sur son évitement. Cette dernière voie de recherche a été introduite pour la première fois en 1999, il s'agit de la datation par radiofluorescence par infrarouge (IR-RF). La méthode permet d'accéder directement à la densité de charges qui se sont accumulées dans les pièges électroniques au cours du temps sans faire intervenir les processus de libération et recombinaison qui interviennent en IRSL.
1 shelter of La Ferrassie (Dordogne, SW France): comparing 2 signals (OSL, IRSL and various post ... more 1 shelter of La Ferrassie (Dordogne, SW France): comparing 2 signals (OSL, IRSL and various post IR-IRSL), materials (quartz 3 and feldspar), levels of analysis (single and multi-grain) and 4 grain sizes (polymineral fine grains and coarse grains). The present study aims at investigating complementary approaches to assess 15 and resolve insufficient bleaching of sediment samples. Firstly, the apparent ages 16 from quartz OSL and different feldspar IRSL signals from coarse-grain, large 17 aliquots, are compared to assess the likelihood of age overestimation resulting from 18 incomplete luminescence signal resetting at the time of burial. Then, a newly 19 developed minimum age model is applied to the single grain OSL D e distribution of a 20 poorly-bleached sample, by disentangling the different sources of dispersion in the 21 measured distributions. 22 Fourteen sediment samples were collected in the entire sequence of La 23 Ferrassie rock shelter (southwest of France), that exhibits fluvial and slope deposits.
Au cours des trente dernières années, la datation des feldspaths par luminescence stimulée optiqu... more Au cours des trente dernières années, la datation des feldspaths par luminescence stimulée optiquement s'est considérablement développée tant au niveau de ses applications géologiques et archéologiques qu'au niveau des méthodologies employées. Pour autant, la question du fading (c'està-dire la « perte de signal au cours du temps ») reste ouverte. D'abord focalisées sur des méthodes de correction du fading dans les feldspaths, les stratégies de recherches se sont progressivement portées sur des méthodes permettant la minimisation du fading, puis plus récemment encore sur son évitement. Cette dernière voie de recherche a été introduite pour la première fois en 1999, il s'agit de la datation par radiofluorescence par infrarouge (IR-RF). La méthode permet d'accéder directement à la densité de charges qui se sont accumulées dans les pièges électroniques au cours du temps sans faire intervenir les processus de libération et recombinaison qui interviennent en IRSL.
The Aquitaine basin, in SW France, has been known for over a century for the wealth of its Middle... more The Aquitaine basin, in SW France, has been known for over a century for the wealth of its Middle Paleolithic sites (300 -35 ky) which have also delivered a significant assemblage of Neanderthal remains. This quite favourable area for prehistoric and paleoanthropological research relates to the widespread presence in the region of rock shelters and caves hosted in limestone formations which were locally dug and shaped by rivers and then partly filled by Quaternary deposits. This context allows a well preserved archiving for the studies of Paleolithic tools and for studying subsistence strategies of human cultures and their climatic and environmental settings. An absolute chronological framework and a review of the archaeological and environmental contexts would for many sites allow researchers to specify the temporal evolution of Neanderthal cultures in the southwest of France. The purpose of the present study is to establish a new chronology for several major burial sites: Roc de Marsal (Charente), La Quina (Charente) and La Ferrassie (Aquitaine).
Uploads
Papers by Marine Frouin
In order to better ascertain the chronological framework of the site, we dated several proxies. Various speleothem samples were processed by U-series using a coupled induced plasma mass spectrometer (ICPMS-MC). The resulting isotopic ratios are beyond the secular equilibrium and show that these samples do not appear to be in direct stratigraphic relation with the archaeological sequence.
Nine Equus teeth were analyzed by the combined ESR/U-series method. These samples were taken from Unit I to Unit XVI representing at least 2.5 m of stratigraphic depth and approximately 90% of the infilling. Many of the dated samples are burnt given that more than 85% of the faunal remains exhibit traces of fire exposure.
The bone retouchers, for which a comparative analysis with other sites has been published (Moigne et al., 2016), were probably produced during the Marine Isotope Stage (MIS 11-5) chronological interval corresponding to the later part of the Middle Pleistocene, inference that is in agreement with the palaeontological assemblage of the site. The radiometric results presented here are consistent and indicate a range from 350 to 183 ka, suggesting that a major part of the sedimentary infilling coinciding with the human occupation was contemporaneous with the MIS 9 to 7 time period.
to 55 ka, provides insight into the Middle Paleolithic peopling of
the Arabian Peninsula. The archaeological layer is interstratified within thick,
sandy silt floodplain deposits filling a piedmont basin. Luminescence dates, lack
of soil development, and gypsum precipitation indicate a high accretion rate of
the floodplain during Marine Isotope Stage 3, in connection with a (semi)-arid
environment. Rapid overbank sedimentation was likely a result of the remobilization
of loess material deposited on the Yemeni Great Escarpment at the
periphery of the adjacent Tihama coastal sand desert or of other sources. Fabric
and size analyses of the lithic artifacts, together with spatial projections, indicate
site modifications by floods. Primary modifications include (1) selective
accumulation of medium-sized lithic pieces as a result of hydraulic sorting, (2)
bimodal orientation of artifacts, and (3) ripple-like arrangement of lithics and
bone/tooth fragments. The overrepresentation of teeth may also be a consequence
of sorting. Although floods have distorted the original site patterning,
long-distance transport of artifacts by water can be excluded, as indicated by
relatively high refitting rate, close proximity of artifacts derived from the same
block of raw material, and lack of abrasion of the pieces. Therefore, the site is
considered “geologically” in situ because its remobilization by water occurred
shortly after human abandonment. This study also stresses that the effective
preservation of a site cannot be assessed without careful taphonomic study,
even in a potentially favorable depositional context such as silty alluvium."
In order to better ascertain the chronological framework of the site, we dated several proxies. Various speleothem samples were processed by U-series using a coupled induced plasma mass spectrometer (ICPMS-MC). The resulting isotopic ratios are beyond the secular equilibrium and show that these samples do not appear to be in direct stratigraphic relation with the archaeological sequence.
Nine Equus teeth were analyzed by the combined ESR/U-series method. These samples were taken from Unit I to Unit XVI representing at least 2.5 m of stratigraphic depth and approximately 90% of the infilling. Many of the dated samples are burnt given that more than 85% of the faunal remains exhibit traces of fire exposure.
The bone retouchers, for which a comparative analysis with other sites has been published (Moigne et al., 2016), were probably produced during the Marine Isotope Stage (MIS 11-5) chronological interval corresponding to the later part of the Middle Pleistocene, inference that is in agreement with the palaeontological assemblage of the site. The radiometric results presented here are consistent and indicate a range from 350 to 183 ka, suggesting that a major part of the sedimentary infilling coinciding with the human occupation was contemporaneous with the MIS 9 to 7 time period.
to 55 ka, provides insight into the Middle Paleolithic peopling of
the Arabian Peninsula. The archaeological layer is interstratified within thick,
sandy silt floodplain deposits filling a piedmont basin. Luminescence dates, lack
of soil development, and gypsum precipitation indicate a high accretion rate of
the floodplain during Marine Isotope Stage 3, in connection with a (semi)-arid
environment. Rapid overbank sedimentation was likely a result of the remobilization
of loess material deposited on the Yemeni Great Escarpment at the
periphery of the adjacent Tihama coastal sand desert or of other sources. Fabric
and size analyses of the lithic artifacts, together with spatial projections, indicate
site modifications by floods. Primary modifications include (1) selective
accumulation of medium-sized lithic pieces as a result of hydraulic sorting, (2)
bimodal orientation of artifacts, and (3) ripple-like arrangement of lithics and
bone/tooth fragments. The overrepresentation of teeth may also be a consequence
of sorting. Although floods have distorted the original site patterning,
long-distance transport of artifacts by water can be excluded, as indicated by
relatively high refitting rate, close proximity of artifacts derived from the same
block of raw material, and lack of abrasion of the pieces. Therefore, the site is
considered “geologically” in situ because its remobilization by water occurred
shortly after human abandonment. This study also stresses that the effective
preservation of a site cannot be assessed without careful taphonomic study,
even in a potentially favorable depositional context such as silty alluvium."