Bertrand Ligouis | Eberhard Karls Universität Tübingen (original) (raw)

Papers by Bertrand Ligouis

PubMed, Jun 1, 2022

Here we present the results of a microcontextual analysis of purported combustion features recove... more Here we present the results of a microcontextual analysis of purported combustion features recovered from Middle and Upper Paleolithic occupations at the cave site of Fumane, Italy. Our analyses, which integrate micromorphology with organic petrology, show that only a few of the features represent primary, intact hearths; some of them show evidence for various phases of anthropogenic reworking, either through trampling or sweeping and dumping. Several of the features are multi-layered and reflect a complex formation history of various activities related to combustion and site maintenance. Many appear to be the remnants of occupation horizons only partially preserved and peripherally related to combustion. Within several of the intact hearths from the Mousterian, we were able to identify variable fuel sources in different features, implying a degree of flexibility in the fuel-selection strategies of the Neanderthal occupants of Fumane. In this study we design a classification system of the anthropogenic features and also conduct a spatial analysis, through which we can infer diachronic patterns in the frequency and intensity of site occupation and the spatial distribution of activities. We note a decrease in frequency of combustion features throughout the Mousterian which continues into the Uluzzian. The features associated with the Protoaurignacian occupation, in contrast with those from the Mousterian, are multi-layered and well-defined. We argue that these trends, which correspond with other trends in artefact frequency, imply changes in the settlement dynamics of the site during the transition from the last Neanderthal occupation of the cave to the arrival of modern humans.

Etude petrographique de la grande couche de charbon de bourran, d'age stephanien b-c, bassin ... more Etude petrographique de la grande couche de charbon de bourran, d'age stephanien b-c, bassin de decazeville. Les variations verticales de la composition du charbon conduisent a un decoupage du profil de couche en intervalles. L'ensemble des caracteres petrographiques d'un intervalle definit un type petrographique. Cinq types sont identifies. L'utilisation des maceraux comme marqueurs botaniques et la confrontation des donnees petrographiques et palynologiques permettent de relier chacun des types petrographiques a un type de vegetation et a un environnement de depot. Ainsi, le depot du charbon a eu lieu dans la partie centrale du bassin, dans une cuvette a subsidence rapide, occupee par une nappe d'eau de niveau moyen a eleve. Le charbon apparait comme un depot allochtone

Environmental Science & Technology, Dec 18, 1999

Sediment organic matter heterogeneity in sediments is shown to impact the sorption behavior of co... more Sediment organic matter heterogeneity in sediments is shown to impact the sorption behavior of contaminants. The authors investigated the sorptive properties as well as the composition of organic matter in different subsamples (mainly grain size fractions) of the Canadian River Alluvium (CRA). Organic petrography was used as a new tool to describe and characterize the organic matter in the subsamples.

Neues Jahrbuch für Geologie und Paläontologie, Nov 18, 1996

International Journal of Coal Geology, Nov 1, 2015

Abstract High resolution organic petrological analysis has been carried out on core samples of th... more Abstract High resolution organic petrological analysis has been carried out on core samples of the Posidonia Shale from four wells, two located in northwestern Germany (Lower Saxony Basin) and two in the western Netherlands (West Netherlands Basin). The organo-mineral microfacies defined by maceral composition and associated mineral matter show a wide range of variations related to the proportions of individual liptinite macerals of marine origin and of terrestrial macerals (macerals of vitrinite, inertinite groups and sporinite). Variations in organo-mineral microfacies, in which the organic components are sensitive to paleoenvironmental changes, are considered as a potential indicator of changes in depositional conditions. Sedimentation of organic matter is controlled by several factors, the most important in the marine environment being primary biomass productivity and influx of transported terrestrial organic matter, biological degradation related to bacterial activity, and the oxygen content of the bottom water. The level of degradation in organic-rich sediments is mainly related to oxygen availability which, in turn, influences the diversity of algae and the quality and quantity of the preserved organic matter. These two factors can be directly linked to maceral preservation and the organo-mineral microfacies. In order to evaluate the relationships between different types of organic matter and paleoenvironmental conditions, two indices, the oxidation index and the degradation index have been proposed. These indices illustrate the transition from highly degraded to well preserved macerals, provide information on the types of organic matter, and permit recognition of precursors for degraded amorphous organic matter (AOM). Use of these indices not only enables determination of the organo-mineral microfacies, but also sheds light on the AOM precursors in the Posidonia Shale. Information derived from the indices can also be used to reconstruct the paleoenvironments.

PLOS ONE

High-resolution sediment analysis allowed us to identify two Middle Bronze Age (MBA 1, 1650–1550 ... more High-resolution sediment analysis allowed us to identify two Middle Bronze Age (MBA 1, 1650–1550 cal a BCE) byre-houses at the waterlogged site of Oppeano “4D”, south of Verona (Veneto region, NE Italy). The site lies in a low-lying valley incised by the Adige River in its LGM alluvial fan. In this fluvio-palustrine environment burial and taphonomic conditions were such that the archaeological record was extremely well preserved. The wooden elements making up basal parts of nine ‘huts’ were in fact exposed at Oppeano, and so were their internal accretion deposits. These featured finely laminated dung units deriving from the stalling of small herbivores, possibly ovicaprids, intercalated with repeated accumulations of wood ash. This was produced in large and multi-stratified hearths that were exposed within each hut. Organic petrology provided evidence of the production of wood tar inside one of the studied structures. At Oppeano 4D it was thus demonstrated that these structures were...

Quaternary Research, 2020

The archaeological assemblage recovered from the Middle Stone Age (MSA) levels in Blombos Cave, S... more The archaeological assemblage recovered from the Middle Stone Age (MSA) levels in Blombos Cave, South Africa, is central to our understanding of the development of early modern humans. Here, we demonstrate that the cultural and technological innovations inferred from the Blombos Cave MSA record also correlate with significant shifts in site use and occupational intensity. Through a comprehensive geoarchaeological investigation of three MSA occupation phases, we identified distinct diachronic trends in the frequency of visits and the modes of occupation. During the earliest phases (ca. 88–82 ka), humans inhabited the cave for more extended periods, but cave visits were not frequent. During the later phases (ca. 77–72 ka), the cave was more regularly visited but for shorter periods each time. We argue that these changes in local occupational intensity, which also coincide with shifts in vegetation, sea levels, and subsistence, can best be explained by broader changes in hunter-gathere...

Journal of Petroleum Geology, 1997

The Chad Basin is the largest intracratonic basin in Africa, and one-tenth of its surface area li... more The Chad Basin is the largest intracratonic basin in Africa, and one-tenth of its surface area lies in NE Nigeria. Thermal maturation (mean vitrinite reflectance) and organicgeochemical (Rock-Eva1 pyrolysis) studies have been carried out on Cretaceous shales from the Bima Formation, Gongila Formation and Fika Shale Formation. Samples were derived from the Kanadi and Albarka exploration wells, which are located about 76 km apart in the Nigerian sector of the Chad Basin. The organic matter is predominantly gasprone (Type III kerogen). Its thermal maturity, assessed from vitrinite reflectance and Tmax, indicates that the Gongila Formation and the Bima Formation are within the "oil window ", while the Fika Shale Formation is only partly within it. The "oil window", deduced from the mean vitrinite reflectance profile, occurs between 1,270m-2,600m in the Kanadi well, and between 1,985m-3,690m in the Albarka well, with respective maturation gradients of 0.52 log%RmL%m (0.41 %Rm/ km) and 0.41 log%Rm/km (0.34%Rm/km). Eroded thicknesses amount to about 1 km. The upperpart of the Fika Shale Formation has the best source-rockpotential in terms of its organic carbon content, but has low thermal maturity. The Gongila Formution is poor in organic carbon and its hydrocarbon potential may already have been exhausted. The Bima Formation is well within the "oil window ", but has only limited potential as a source rock, because of the presence of elastic and inert materials. The potential for gas accumulations, however, exists.

Bulletin De La Societe Geologique De France, Mar 1, 1991

Archaeological and Anthropological Sciences

Archaeological Soil and Sediment Micromorphology

Journal of Archaeological Science: Reports

Abstract Natural, anthropic and post-depositional formation processes can affect the formation of... more Abstract Natural, anthropic and post-depositional formation processes can affect the formation of sediments in rock shelters. Geoarchaeological analyses were carried out on a series of samples of compact and loose sediments provenient from the 1995 to 2005 excavation campaigns at the Atxoste shelter. This work focuses on climate reconstruction of the Upper Ebro Valley, comparing it with results of previous studies of the area and its surroundings, as well as the Cantabrian region. We also point out the problem of sediment conservation when analyzing sites containing Pleistocene/Holocene and/or Mesolithic/Neolithic transition stratigraphies. Thanks to the geoarchaeological study we have differentiated three climatic events: - The end of the Pleistocene as a period characterized by cold, humid conditions and with probable seasonal droughts. - The Pleistocene-Holocene transition that corresponds to a climatic moment in which the indicators of cold climate have practically disappeared. - The beginning of the Holocene, when a significant and rapid climatic improvement takes place, with an increase in temperatures, a decrease in rainfall but maintaining the humidity. The identification of the different post-depositional processes has been key to identifying the state of the recovered archaeological material. Therefore, this study is based on the geoarchaeological analysis, approaching the period central to this paper (Pleistocene-Holocene transition). This is crucial in order to obtain a better understanding of the paleoecology and archaeological aspects.

Laurence Frei Paroz Iann Gaume caj 25 cahier d'archéologie jurassienne Occupations des Premier et... more Laurence Frei Paroz Iann Gaume caj 25 cahier d'archéologie jurassienne Occupations des Premier et Second âges du Fer dans le bassin de Delémont DELÉMONT-EN LA PRAN 4 2012 Avec des contributions de

Southern African Humanities, 2016

Elands Bay Cave is a small coastal rock shelter formed in quartzite that contained up to ca. 3 m ... more Elands Bay Cave is a small coastal rock shelter formed in quartzite that contained up to ca. 3 m of anthropogenic and geogenic deposits with archaeological materials dating to the Middle Stone Age through Later Stone Age. Today, only the lower portion of the sedimentary sequence, comprising ca. 1.2 m of sediment remains. A geoarchaeological study of the remaining deposits was undertaken in conjunction with renewed excavations of the site (2010–2012). A ground penetrating radar survey revealed that the excavation area targeted the deepest portion of the sedimentary infill within the rock shelter. Furthermore, micromorphological analyses of the remaining Middle and Later Stone Age deposits indicate that combustion features are present. Fourier transform infrared spectroscopy and x-ray diffraction measurements were used to identify secondary minerals, including taranakite, hydroxylapatite, gypsum, variscite, ardealite, opal, and whitlockite. The distributions of these secondary mineral...