dAf 103
SORDOILLET Dominique
Géoarchéologie de sites préhistoriques
Le Gardon (Ain), Montou (Pyrénées-Orientales) et Saint-Alban (Isère)
In this work, Dominique Sordoillet accomplishes the difficult task of rendering a previously obscure discipline accessible to everyone. This work originates from her doctoral dissertation thesis, which received unanimous praise for its methodological and scientific rigor. Drawing on elements from the earth sciences, she studied the stratigraphy of three exemplary archaeological sites. The prehistoric sites of Gardon, Montou and Saint-Alban were thus subject to a precise micromorphological analysis, which considers a stratigraphy as a sedimentary record of time. Through a classification of the deposits into two large families based on their formation processes, she distinguishes the occupation facies, created by human activities, from the abandonment facies, which are characteristic of natural sedimentary and post-sedimentary processes. Based on these sedimentological data, replaced in their chronological and cultural contexts, she proposes different occupation scenarios and interpretations of the evolution of human activities, rituals and construction.
This short, well illustrated presentation is written with a simple vocabulary and includes a glossary, all of which make it an effective tool for understanding the methods and objectives of micromorphology in the direct interest of field interpretations and methods.
Abstract
Abstract
After a foreword that recalls the importance of multidisciplinarity in the history of archaeological research, followed by its gradual shift toward transdisciplinarity and the logical emergence of fields such as geoarchaeology, the introduction to this work describes how the sedimentary deposits of archaeological sites can yield information concerning human occupation modes. Aspects such as site function, spatial organization and the duration of site occupation and abandonment are addressed. This study also enlarges the micromorphological reference base of archaeological sedimentary facies, thus contributing to the definition of sedimentary processes typically related to human activities. The sites studied, two in caves and one in the open-air, are then presented.
1 - Methodology
Two successive and complementary approaches, stratigraphy and micromorphology, were employed in this study of archaeological sites. This procedure resulted in an understanding of the deposit formation processes and by extrapolation, those of the human occupations. The bases of stratigraphic analysis are presented and adapted to the archaeological procedure and three types of stratigraphic seriation are defined: lithological, cultural and chronological (fig. 7). The interest and limits of these classifications are discussed. The application of micromorphology to archaeology is then presented. Based on the description and comparison of “in situ” deposits, this method constitutes a logical continuation of fieldwork research. The method and principles of description, as well as the history of research concerning anthropogenic sediments are also presented. Some of the interpretations reached rely on experimental thin sections taken from samples coming from modern, well defined contexts (pl. A1-A7).
2 - Gardon Cave
Gardon Cave, the over-flow section of a small karstic system in the southern Jura region, was repeatedly occupied from the Early Neolithic to the Middle Ages. Its stratigraphic analysis led to the definition of around one hundred sedimentary levels that were grouped into fifteen lithological formations (fig. 16; tabl. IV). The similarities and dissimilarities observed between the lithostratigraphy and the cultural sequence show that the sedimentary and cultural processes were independent, while the radiocarbon dates reveal a cause and effect relationship between the genesis of alluvial formations and periods of climatic deterioration (fig. 27, 28). Throughout the study, the sedimentary deposits of each formation are interpreted in terms of occupation dynamics and human activities. The question of the duration of occupation and abandonment periods is also addressed, as well as that of environmental conditions. Among the contributions of this study, the following are significant at Gardon Cave: a revision of archaeological fieldwork interpretations, a proposition of archaeological interpretations based only on sedimentary analyses, and a demonstration of the chronoclimatic potential of the archaeological deposit.
3 - Montou Cave
The characteristics of Montou Cave in the Pyrénées-Orientales region are very different from those of Gardon. Here the occupations, extending from the Neolithic to the Bronze Age, are located in an obscure gallery a few meters from the entrance. The stratigraphic analysis resulted in the description of around sixty levels grouped into six principal formations. In contrast to what was observed at Gardon Cave, the limits defined by the lithostratigraphic and chronocultural divisions are globally concordant here, emphasizing the predominant role of anthropogenic sedimentation. In addition, several site abandonment facies were identified, which can be classed according to the supposed necessary duration of them. The sedimentary rhythms suggest that the occupations were discontinuous and relatively regular during the Neolithic, while they were more episodic during the Bronze Age. The history of the Neolithic deposition is divided into several principal periods during which around twenty occupation phases occurred and were separated by abandonment phases of varied durations (fig. 33, 34). The Bronze Age occupations, also attributed to seven principal periods, were more episodic (fig. 35).
4 - Saint-Alban
Located in a narrow incurvation at the top of a rocky spur, the site of Saint-Alban is characterized by its two meter thick deposit of finely stratified anthropogenic levels. The occupation levels are dated to the Final Bronze IIIa, the Final Bronze IIIb and the Early Hallstatt periods. The deposits appear to be primarily related to the modification and occupation of the site. While the archaeologist estimates that there are twenty occupation floors, the lithostratigraphic analysis indicated four principal cycles of occupation-abandonment during which there were twelve phases of construction. Throughout this study, these two divergent hypotheses were continuously confronted, in some cases leading to revisions or modifications of the conclusions of both (fig. 42).
5 - Sedimentary microfacies, human activities and occupation rhythms
The comparative study of the data obtained at these archaeological sites revealed sedimentological regularities that are globally transposable from one site to another and which explain the general aspects of anthropogenic sedimentation and site formation processes. The results of this work lead the author to propose a definition, or redefinition, of the notions of occupation floors and levels and abandonment levels and sub-levels, while discussing the fact that these can be monophase or polyphase levels and can correspond to variable occupation durations (fig 43, 44). A classification of the sedimentary occupation and abandonment phases described at the different sites is also proposed (fig. 46). From this basis, the history of the sites can be reconstructed in terms of human activities, spatial organization, occupation rhythms and environmental conditions. These interpretations, and the generalizations that can be drawn concerning anthropogenic sedimentary dynamics, nonetheless have limits, which are illustrated by the existence of deposition facies that are unique to each site.
The conclusion to this study emphasizes the principal information obtained, whether methodological or more directly related to archaeological and environmental questions. The contributions and limits of stratigraphic and micromorphological studies, as well as the importance of confronting and integrating data from diverse archaeological and naturalistic disciplines, is recalled. The cognitive potential of the sites studied is also emphasized, with the final point being that all geomorphologic contexts have a potential interest for archaeological knowledge.
