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La géoarchéologie française au xxie siècle

 | 
Nathalie Carcaud
, 
Gilles Arnaud-Fassetta

Partie IV. Ressources en eau, risque et aménagement/Section 4. Water resources, risk, and management

Chapter 18. Dark Earth in the geoarchaeological approach to urban contexts

Quentin Borderie, Yannick Devos, Cristiano Nicosia, Cécilia Cammas et Richard I. Macphail

Texte intégral

Introduction

1In urban contexts, which are essentially anthropogenic, the processes of accumulation, transformation and erosion are particularly intense and diversified (Cammas et al., 2011). These processes proceed from the urban fabric, by through dynamic interactions between societies and the materiality of spaces (Noizet, 2009). The strata resulting from the combination of these socio-environmental dynamics are more or less easily interpretable in terms of the human use of space. Any diiculties of interpretation are both linked with the interpretive frameworks and the pedo-sedimentary history of these strata. Among these contexts, Dark Earth are thick dark layers, which appear to be homogeneous and constitute the main archaeological documentation of towns from the 4th to the 11th c. Although they have been known and observed since the 19th c., specific protocols of excavation, stratigraphic analysis, archaeology and geoarchaeology have only been applied since the 1980s.

Fig. 1. Dark-Earth stratifications. A: Bayeux, rue Franche (photo: G. Schütz, 2010, Service Départemental d’Archéologie du Calvados). B: Beauvais, la Chapelle (photo: Q. Borderie, 2007). C: Metz, Sainte-Chrétienne (photo: S. Augry, 2008, Institut National de Recherches Archéologiques Préventives). D: Evreux (photo: B. Guillot, 2001, Institut National de Recherches Archéologiques Préventives).

The geoarchaeological approach of urban contexts

2The frameworks for the geoarchaeological study of urban landscapes was established in the early 1980s (Hall and Kenward, 1982) and strongly influenced by geography and geomorphology. These early work suggested that towns and cities should be perceived as artefacts whose taphonomy becomes the focus of the study (Rosen, 1986). These studies also established the foundations for the analysis of relations between the development of cities and their surrounding environment (Butzer et al., 1983). Actually, the urban landscape is the result of the deposition of heterogeneous materials, provided for construction, craftproduction or consumption and subject to decay and post-depositional transformation, and autogenic or allogenic additions (Borderie, 2011a), whether they proceed from purely urban activities, or from interactions with the environment (catchment, river, coastline).

3Until the late 1990s, studies mainly dealt with large scales of hydrosystems, due to the collaboration between archaeologists and geographers during major urban rescue excavations. These enabled the development of the analysis of relationships between hydrosystems or coasts and towns, notably the study of inputs originating from outside the town, and external hydrological influences (CNAU, 1988; Bravard et al., 1989), which are still studied today (Chaussée et al., 2009). For example London Dark Earth was first thought to be a River Thames ‘flood loam’ (Macphail, 1981). On a much smaller scale, approaches limited to intra-site archaeological operations, including the analysis of Dark Earth, then enabled the establishment or refinement of the understanding of functional interpretations of spaces, both in the Middle East (Matthews, 1992; Matthews et al., 1995, 1997) and in France (Lattes; Cammas, 1994). However, these geoarchaeological approaches remained underused. For instance, only 9 articles dealing with urban contexts have been published by the international journal Geoarchaeology from 1987 to 2010.

4In more recent works, the gap between these very fine, or very broad scale studies has been reduced, by combining the study of the stratification processes and the configuration of the urban site (environmental conditions, local sedimentary resources, etc.) with its evolution (Schwien et al., 1998; Arlaud, 2000; Deschodt and Sauvage, 2008). The nature of urban soils and deposits and their transformation, forced by activities directly or indirectly perceptible (e. g., pollution), is perceived as a co-construction of socioenvironmental dynamics (Heimdhal, 2005; Davidson et al., 2006; Golding, 2008; Noizet et al., 2011). By the 1980s, the study of Dark Earth was already part of this multi-scale perception of socio-environmental dynamics (Macphail, 1981), because their occurrence in the urban context is the main evidence for human activities for the 4th to 11th c.

Dark Earth and the urban stratification

5Dark Earth strata are located between those of antiquity (before the 4th c.) and of the Middle Ages (after the 11th c.). The latter are more easily interpretable because they constitute numerous stratigraphic units (SU), resulting from distinct actions such as excavation, construction and spreading… thus forming archaeological features (such as walls, mosaics, cesspits, etc.).

6Until the 1980s, the apparent homogeneity of massive Dark Earth SU has led to interpretations of its origin, with suggestions including its formation from urban abandonment, thick embankments or the cultivation of urban areas. These interpretations thus maintained the pervading models of cities portrayed as without active urban life, weakened by the attacks of the barbarians and abandoned by the elites (Galinié, 2010). Since the beginning of the 1990s, the geoarchaeological approach has enable the reconsideration of these interpretations, and shown how Dark Earth can be derived from a complex combination of different processes, whose results are similar only at a macroscopic scale (Macphail, 1994; Cammas et al., 1998; Devos et al., 2009). Recent work (Cammas, 2004; Nicosia, 2012; Borderie, 2013) at a finer scale than the SU show that this Dark Earth SUs can even contain an internal structure, such as gradients or distributions of coarse constituents colours, and sometimes even include smaller structures (such as post holes, fireplaces or interior floors). This internal structure invites us to consider the importance of pedogenic processes in the transformation of deposits, which can but may not lead to the homogenisation of the sediment, in a context – the town – where everything is constrained by human activity. Information on the SU-formation processes (filing and transformation), as well as the characteristics of the SU, therefore enables us to understand the activities that are operating at the time of their origin, and therefore the functions of urban places in late Antiquity and the early Middle Ages (Fig. 2).

Fig. 2. Space functionalities, activities and formation processes of Dark Earth. Dark Earth are the result of complex formation processes, linked with environmental conditions (dry, wet, indoor, outdoor…) and, most of all, to activities and land use, as to their action to the soil/sediment. Thus, the functionalities of the spaces in which Dark Earth can be formed are often multiple and they can vary through time.

Methods for the study of Dark Earth

The topographic approach

7Layers of Dark Earth from the 4th to the 11th c. are found in a very large number of towns in the Northwest of Europe (Macphail et al., 2003; Verslype and Brulet, 2004). However, within each town, or from one town to another, this occurrence has not yet been quantified. The establishment of a systematic survey is useful in order to register macroscopic characters of urban sediments such as maximum and minimum extension and thickness, colour, apparent stratification, etc. The location of Dark Earth in relation to structural elements of space is a significant archaeological evidence of the use of space and whether these elements are contemporary, younger or older. For example, the proximity of strata to town walls, religious buildings, and urban thoroughfares, alleyways or routeways, assists with the understanding of the use of the spaces, the relationships between society and the urban ground and the organisation of urban spaces, for a period where the use of the urban plot is almost unknown.

The stratigraphic approach

8Firstly, in order to gain an overall vision of the organisation of spaces and activities, thick layers of Dark Earth should not be separated from the thinner SUs nor from the archaeological structures they may contain, and in which they are located (pit-houses, trenches, ditches…), or which are adjacent. Indeed, the different dynamics of accumulation and deposition can be understood by comparing contexts (i.e., indoor and outdoor spaces).

9Then, excavation by SU and horizontally when the SUs are very thick and difficult to understand, is the only reliable method in order to identify and to record vertical and lateral variations of the sedimentary characteristics and the concentrations of macro-components of a diameter greater than a few centimetres (David, 2004). The organisation of the layers can then be observed over several metres distance, including the densities and types of macroconstituents observed (fragments of pottery, tile, mortar, charcoal, slag, stones, etc.), as well as those of the structures themselves such as aggregates and alignments of components such as postholes and pits (Gébus and Gama, 2004). The arrangements thus identified can sometimes be correlated with topographic features e.g. thoroughfares, buildings, etc. Finer variations can also be perceived through the observation of macro-constituents organisation in sediments and by analysing latent structure (i.e., their spatial distribution in three dimensions). Different phases of input and reworking may well be highlighted (Borderie and Petronille, 2009). Finally, at the finer scale, micro-stratification can be identified and can assist in the identification of the processes of accumulation.

Characterisation of stratigraphic units

10The nature of the inputs contributing to Dark Earth may be informed by the characterisation of the SUs (e.g., charcoal, organic matter, phosphorus, heavy metals). In addition to their extrinsic characteristics, including their stratigraphic position, these characters can be used to identify the intrinsic process of accumulation and transformation. Furthermore, in support of the archaeological description, they allow the comparison of one SU with another by quantitative or semi-quantitative criteria. Table 1 lists the main methods used to characterise Dark Earth SUs. A more detailed inventory is given by Borderie (2011, p. 81-82).

Fig. 3. Examples of micro-elements in Dark Earth. Dark Earth contains many different micro-elements. Their combination and their state contribute to the identification of processes and activities taking part in the Dark Earth formation. A: Lead droplet embedded in calcitic ash (PPL, late Roman Dark Earth, Vine st. Leicester). B: As A but under oblique incident light showing black lead (centre), ‘red’ lead oxide (edge) and lead carbonate (contaminated ashes; Thilo Rehren, UCL, pers. com.). C: Vivianite cristal (Iron phosphate) in a bone pore (XPL, early Middle Ages, A. Briand pl. Noyon). D: As C but under PPL. E: Gypsum crystal (PPL, Sainte-Chrétienne Metz). F: Grapes seed (PPL, A. Briand pl. Noyon). G: Burned bone fragment on a thin calcitic ash layer (XPL, Grospiron sq. Noyon). H: As G but in PPL.

References

Quantitative study of coarse or fine components

Desachy. 2000; Sidell. 2000: Guyard, 2003; David. 2004; Laurent, 2004; Fondrillon. 2007

Pottery

Jouquand et al. 1999; Guyard, 2003: Jaffiot, 2008; Augry et al., in press

Grain size

Guyard. 2003: Macphail and Linderhohn. 2004: Fondrillon. 2007: Devos et al, 2009

Counting on thin section

Gebhardt, 1997; Nicosia et al, 2012; Devos et al, 2009

Micromorphology

Macphail, 1981; Macphail, 1994: Gebhardt, 1997; Cammas et al. 1998: Cammas, 2004: Macphail and Linderholm. 2004: Devos et al. 2009; acphail, 2010: Borderie. 2011b; Nicosia et al., 2012; Broderie2013

Pollen analysis

Macphail. 1981; Guyard. 2003: Brulet et al, 2004

Macro remains

Laurent. 2004

Phytolith analysis

Devos et al., 2009

Malacology

Guyard. 2003

Parasitology

Guyard, 2003

Archaeozoology

Guyard. 2003: Bralet et al., 2004

Geochemisten (metals)

Macphail et al. 2008 : 93-96: Borderie, 2011b; Augry et al., in press

Chemical analysis (organic matter)

Guyard. 2003: Macphail. 2003: David, 2004: Fondrillon, 2007: Borderie, 2011b: Nicosia et al., 2012

Geophysical remote sensing

David, 2004

Geophysical data (magnetic susceptibility)

Macphail, 2003; Borderie. 2011b

Tab. 1. Methods used to analyse Dark Earth.

Micromorphology

11Micromorphology has been used to study the Dark Earth since the early 1980s in Britain (Macphail, 1981; Macphail, 1983; Macphail and Courty, 1985; Courty et al., 1989) and the 1990s in France (Cammas et al., 1995; Gebhardt, 1997).

12Micromorphology is the study of the organisation of soil components at the microscopic scale, which is indicative of the dynamics of depositional environments and the evolution of soil profiles (Cammas and Wattez, 2009, p. 186). Undisturbed archaeological sediments and soils are observed from field to microscope (Courty and Fedoroff, 2002) using the interpretative concepts of sedimentary petrography and soil science following soil-micromorphology handbooks (Bullock et al., 1985; Stoops, 2003). Analysis of micro-components, the fine fabric of archaeological sediments and their relative organisation, can then help us to “understand their formation and the manner in which they enter the archaeological record” (Goldberg and Macphail, 2010, p. 589), including the identification of micro-stratigraphic units (MSUs) or micro-facies types (Courty, 2001; Cammas and Wattez, 2009).

13The interdisciplinary approach, combining micromorphological methods with geophysical, geochemical, quantitative and qualitative studies of artefacts, can quickly generate results, which can contribute to the interpretation of Dark Earth and a more general understanding of the formation process of urban stratification. Moreover, recent works show how the systematisation of these approaches is extremely profitable as it permits us to revisit the interpretations of ‘gardens’ or ‘abandonment’, which have not been established by other studies, and can demonstrate the multiplicity of processes that can potentially produce Dark Earth (waste, housing, animal housing, crafts…). It can therefore, ultimately, renew our perception of urban spaces in the city from the 4th to the 11th c.

Results

Physicochemical and stratigraphic characterisation of the Dark Earth

14The identification of Dark Earth is based on the macroscopic observation of its colour, thickness and apparent homogeneity. Yet these characters, as well as physical and chemical characteristics, show strong variations, from one city to another, as well as from one SU to another within the same archaeological excavation.

15The thickness of Dark Earth is often accepted as being between 0.4 and 0.8 m (Courty et al., 1989, p. 263; Macphail et al., 2003). However, it is sometimes thicker and it often shows in a systematic manner, at both field and microscopic scales, finer stratifications or gradients of colour, textures, artefacts and concentration features (Verslype and Brulet, 2004). Sometimes, these strata consist of the superposition of many SUs, which can be seen with the naked eye (Borderie, 2011b, p. 241-281).

16Similarly, the colour of Dark Earth is variable. The strata are most often of dark colour (7.5 YR 5/1 to 10 YR 2/1), due to the large presence of fragments of charcoal and burnt plant remains often observable by eye, and organic matter observable under the microscope. However, this colour varies within strata and gray-coloured Dark Earth, towards a more yellow or even green colour, depending on their content of charcoal micro-fragments, iron and phosphate (Macphail, 1994; Borderie, 2011b, p. 311-328; Fig. 3).

17The physicochemical characteristics of Dark Earth result from both local pedo-geochemical conditions and inputs related to activities and their transformations. Thus, although Dark Earth are, in most cases, silty-sands, they are not well sorted and can be much more sandy in some alluvial contexts (see Macphail, 2003, p. 92-93; Heimdhal, 2005; Borderie, 2011b, p. 338-339; Nicosia, 2012, p. 115). Similarly, Dark Earths contain a generally low amount of carbonate in Britain or Belgium (Macphail, 2003, p. 92-93; Devos et al., 2009, p. 273) while they contain more in the Paris basin (Borderie, 2011b, p. 340-345; Fig. 4). However, a significant proportion of these carbonates can come from the presence of derelict building materials such as mortar or limestone (Macphail, 1994, 2010).

18Associations of components in the Dark Earths are, thus, very variable and reflect the nature of the inputs and the activities that produced them. Components larger than a few centimetres are most of the time altered building materials: stone tools, mortars, tiles, plaster (Guyard, 2003, p. 95; Fondrillon, 2007, p. 434 and 442). Fine components of sands and silts, are particularly relevant to the diversity of activities during the early formation of Dark Earths (Macphail, 1994, 2010; Borderie, 2011b). These components are partly the result of inputs from building materials (limestone, quartz, ceramic tiles), but they also come from domestic activities (manure, bones) or craftactivities using plants (phytoliths) and fire (ash, micro-charcoal fragments), sometimes formed at high temperatures (slag, fused silica, glass). The occurrence of weathered lead fragments embedded in ash in late Roman Dark Earth in Leicester, UK is an example of such artisan work (Macphail and Crowther, 2009; Fig. 3 A and B). The condition of these components – burnt, rolled, twisted, broken up – and their organisation within the fine fabric, provide evidence of the use of spaces and the frequency of their occupation.

Fig. 4. Organic carbon and calcium carbonate content in Dark Earth. The carbonated Dark Earth, on the right, is here all located in the Paris basin. Dark earth from Great Britain and Belgium are less carbonated. Organic carbon content is higher than 10 g/kg and can reach 25 g/kg. The strata underlaying the Dark Earth, which are Roman occupational layers or alluvial substrate, or earthworks, show lower amount of organic carbon. 1: Collège de France; 2: Metz Sainte-Chrétienne; 3: Beauvais Galerie nationale de la tapisserie; 4: Beauvais Cloître; 5: Beauvais Chapelle; 6: Noyon Evêché; 7: Bayeux Rue Franche; 8: Metz ZAC Amphithéâtre; 9: Noyon Square Grospiron; 10: London Ragoon st.; 11: London Southwark st.; 12: London Southwark Courage Brewery; 13: London Southwark Park st.; 14: London Jubilee Hall; 15: Florence Biblioteca; 16: Brussels Rue de Dinant; 17: Beauvais Galerie nationale de la tapisserie, earthwork; 18: Noyon Cloître cathédral, earthwork; 19: Metz Sainte-Chrétienne, Roman deposits; 20: Beauvais Chapelle, Roman pit filling; 21: Metz ZAC Amphithéâtre, alluvial substrate; 22: London Jubilee Hall, clay floor; 23: Florence Biblioteca, alluvial substrate; 24: Brussels Rue de Dinant. After Macphail, 1994; Cammas, 2004; Devos et al., 2009; Borderie, 2011b; Nicosia et al., 2012; Augry et al. Borderie, 2012.

19Dark Earth has significant levels of organic matter. In addition to micro-charcoal fragments and plant fragments, Dark Earths have high C/N ratios and typically a high phosphorus content (15.5-25.5 g/kg; Borderie, 2011b, p. 342-343, with the method proposed by Mikkelsen, 1997). High contents of heavy metals, due to ancient polluting activities and contemporary with the formation of Dark Earths, have been recorded at more than 1800 mg/kg in Metz (Augry et al., in press). Chemical data, without soil micromorphological control needs to be interpreted with caution as post-Dark Earth land use has led to both phosphate (Deansway, Worcester, Anderitum/Pevensey Castle; Macphail, 2004, 2011) and heavy metal (London Guildhall; Macphail et al., 2008) contamination from Saxon and early Mediaeval disposal of cess (Fig. 4).

Formation processes

20Most often, Dark Earth is composed of a succession of numerous thin inputs, directly reworked by biological activity, as a cumulative soil (Cammas et al., 1998). The MSUs (micro-stratigraphical units), which can then be observed, result from the combination of the volume and the frequency of the inputs, the intensity of the bioturbation, trampling, and the humidity of the environment. Indeed, competition between these processes determines the creation of interfaces and their preservation. When interfaces are not visible to the eye, it is through the organisation of the microfabric that the succession of surface and sub-surfaces layers can be identified microscopically. In all cases, these accumulations are characteristic of progressive inputs, more or less rhythmic, which persist over time. Dark Earth can also result from the inputs made for urban layout (floors, spreading of materials…), excluding massive deposits. The latter, suggests substantial earthwork or dumps and generally constitute only a very small part of the whole Dark Earth. Interior spaces are, in most cases, relatively easy to identify in the field and include; floors, occupation deposits, cleaning/maintaining, etc. However, the transformation processes of stratification can make them less easily identifiable and interpretable. Thus, at A. Briand in Noyon (France), a succession of inputs was characterised by thin ash deposits, weakly bioturbated, containing small and fragmented constituents. They were overlain by fine plant fragments and sometimes coarse constituents in thin layers with sub-horizontal porosity. The large number of bio-nodules and the weak aggregation suggest a resumption of earthworm activity, which had been interrupted by rapid burial and compaction (Borderie, 2011b, p. 282-295).

21The apparent homogeneity of Dark Earth is, above all, due to the simultaneous combination of depositional processes and bioturbation, rather than a partial or total restructuring of stratification. The most homogenous units of Dark Earth can result from mechanical processes of reworking, such as tillage (Devos et al., 2009). However, even in these thick units, it is possible to perceive different processes and inputs due to the superimposition of pedo-sedimentary features (Borderie, 2013). The part played by bioturbation processes in the formation of Dark Earth was demonstrated in the 1980s by Macphail (1981, 1994). In most cases, this bioturbation indicated spaces, which had been weakly trampled, as the results from similar studies from Paris (Cammas, 2004, p. 49) and Metz (Gébus and Gama, 2004) have shown. However, such bioturbation may also be accompanied by substantial archaeological evidence for the use of these areas, as at Beauvais (Borderie, 2011b, p. 249-254 and 280-281), in Paris and Macon (Cammas, 2004, p. 49 and 53). It may even take place in refuse areas of interior space, as at Beauvais and Noyon (Borderie, 2011b, p. 265-274 and 316-319).

22The role of percolation and stagnation of soil water in the formation of Dark Earth has been demonstrated by Macphail (1994). Both can contribute to the dissolution of some constituents, including carbonate, which can also be altered by variation in the acidity of the sediment. The conservation of ash lenses (Fig. 3 G and H), which are particularly prone to dissolution, has also been observed, as at Noyon (Borderie, 2011b, p. 284-295). In this situation preservation can then be explained by the speed of burial by relatively impermeable materials such as clayey-sand and particularly compacted strata. Damp environments can also cause the formation of vivianite. These iron phosphate crystals (Fig. 3 C and D) may form in the sub-surface contexts, outdoors, in indoor floors (Borderie, 2011b, p. 337). It is indicative of the amount of phosphate materials in the deposits, usually derived from faeces or bone (Courty et al., 1989, p. 267) and the decomposition of plants (McGowan and Prangnell, 2006). Therefore, the formation of Dark Earth results from a complex combination of the processes of accumulation and transformation associated with the use of space and the nature of prevalent materials.

Beyond Dark Earth

From Dark Earth to urban life in the early Middle Ages

23Detailed understanding of the formation of Dark Earth is very valuable for informing us about human activities in urban environments with such information including the sources of the inputs, inout characters and input transformations.

24In Dark Earth, information from the nature and transformation of properties can assist us in the interpretation of site function because the nature of the strata and functional transformation are very closely intertwined. However, SUs have, moreover, broad rates of formation and, thus, it is rarely possible to give the precise location and intensity of activities, which contributed to their formation. Functional interpretative grids that are usually used for the interpretation of archaeological structures and urban spaces (CNAU, 2007) are difficult to adapt for Dark Earths. Indeed, if progressive accumulations of waste contain evidence of domestic and craft activities, but at a microscopic scale, it requires an important interpretative leap to be made as if the data is to be regarded as evidence of spaces dedicated to “craft” or “housing”. The vast majority of these indices are situated in deposits, which are interpreted as being due to repeated dumping. Although the spaces, where this dumping is located, are sometimes interpreted as dumping areas, the studies made on waste disposal in ancient and Mediaeval urban contexts suggest that these spaces can have other functions in addition to the regular reception of waste (Keene, 1982; Bridges, 1991; Leguay, 2003; Bourgeois, 2003; Golding, 2008; Macphail, 2010).

25The superimposition of the accumulation processes and the richness and rhythmic characteristic of the refuse origin of Dark Earth can suggest, moreover, important functional changes over time and multi-functional spaces, in waste accumulation in activity areas with diffuse boundaries. The very high content of lead recorded in Metz (Augry et al., in press) shows how intense and polluting artisanal work (but probably requiring light infrastructure), can be detected by the sedimentary composition of the associated Dark Earth.

To be continued…

26The study of Dark Earth is of major importance in the history of societies from the 4th to the 11th c. in Northwest Europe. Benefiting from recent advances in geoarchaeology applied to urban contexts, the study of Dark Earths has been advanced through the implementation of interdisciplinary approaches. Dark Earth strata are the result of a combination of processes related to environmental conditions and, especially, socio-spatial practices. Even if a component of some processes comes from outside the city, such as the case of alluvial deposits (Heimdhal, 2005; Nicosia et al., 2012), “natural” process are only discernible when considered in the context of their socialenvironmental co-construction.

27Dark Earth is not synonymous with abandonment, and it is seldom the result of an urban practice of horticulture. Dark Earth strata are mainly the result of gradual accretion, by deposition and transformation in situ, of the wastes of urban activities that produce and release various composite materials, especially organic, in spaces which can be dedicated to various functions, and which can be both indoor or outdoor. This particular type of waste disposal and, finally, this particular relationship to the ground, raises the question of the relationship between the use and the status of some spaces,–such as the presence of Dark Earth near the cathedrals at Beauvais, Noyon, Paris, Rouen and Reims, or their absence inside the internal bank of the walls of late Antiquity sites such as at Noyon and Evreux.

28Dark Earth is a very rich source of ‘documentation’, which has only recently begun to be extensively exploited. Extensive spatial and temporal data can be collected if Dark Earths are studied systematically. The protocols are now well defined for the analysis and interpretation of formational and diagnostic processes, which can provide valuable information on human activities in their urban environment. A better understanding of the urban contexts from the 4th to the 11th c. can therefore now be gained, through multiplying the number of observation points, by different form of comparisons, and by the establishment of a repository or archive at the town scale. Greater accuracy in chronology will lead, moreover, to a better spatio-temporal perception of urban dynamics. Finally, the detailed analysis of certain components and characteristics of Dark Earth, such as organic matter, concentrations of heavy metals and microcharcoal fragments, is proving particularly promising. This information, stored in Dark Earth, is the imprint of the life-ways and life-conditions of early Mediaeval urban societies.

Bibliographie

References

Arlaud C., « Lyon, les dessous de la Presqu’Île, Bourse-République-Célestin-Terreaux, Sites Lyon Parc-Auto », Documents d’archéologie en Rhône-Alpes, no 4, Série lyonnaise, no 20, Lyon, Service régional de l’archéologie, 2000.

Augry S., Borderie Q., Braguier S., Prouteau R., Delage R., «L’îlot Sainte-Chrétienne à Metz: un exemple d’approche interdisciplinaire pour caractériser l’occupation urbaine du ive au xiie siècle.», in Actes du Colloque de l’AFAM, septembre 2010, Luxembourg, 2013, p. 23-40.

Borderie Q., « Géoarchéologie de l’urbain, retour sur la journée d’étude du 29 octobre 2009 », Les Nouvelles de l’Archéologie, no 123, 2011, p. 61-64.

Borderie Q., L’espace urbain entre Antiquité et Moyen Âge, géoarchéologie des terres noires: études de cas, Thèse de doctorat, Université de Paris 1 - Panthéon Sorbonne, Paris, 2011.

Borderie Q., « De la matrice sédimentaire aux pratiques socio-spatiales : deux stratifications de terres noires à Noyon (Oise) », in ArcheoDoc, no 5, sous presse.

Borderie Q., Pétronille M., « Susceptibilité magnétique et distribution 3D en niveaux archéologiques perturbés, l’exemple de l’opération archéologique préventive de la ZAC – Amphithéâtre à Metz », in Colloque Archéométrie 2009, Montpellier, 2009.

Bourgeois L., « Archéologie médiévale et déchets urbains, orientation bibliographique », in Ballet P., Cordier P., Dieudonné-Glad N., La ville et ses déchets dans le monde romain: rebuts et recyclages, Actes du colloque de Poitiers, 19-21 septembre 2002, Montauban, Monique Mergoil, 2003, p. 313-314.

Bravard J.-P., Burnouf J., Vérot A., « Géomorphologie et archéologie dans la région lyonnaise: Questions et réponses d’un dialogue interdisciplinaire », Bulletin de la Société Préhistorique Française, no 86, 1989, p. 429-440.

Bridges E.M., «Wasted materials in urban soils», in Bullock P., Gregory P. J., Soils in the Urban Environment, London, Blackwell Sc. Publ., 1991, p. 28-46.

Brulet R., Coquelet C., Defgnée A., Pigière F., Verslype L., « Les sites à « terres noires » à Tournais et le secteur des anciens cloîtres canoniaux. Études archéozoologiques, palynologiques et contextualisation», in Verslype L., Brulet R., Dark earth - Terres noires, Actes de la table ronde de Louvain-la-Neuve, Louvain-la-Neuve, Université catholique de Louvain, 2004, p. 152-172.

Bullock P., Fedoroff N., Jongerius A., Stoops G., Tursina T., Handbook for soil thin section description, Wolferhampton, Waine Research Publications, 1985.

Butzer K.W., Miralles I., Mateu J. F., «Urban geo-archaeology in medieval Alzira (Prov. Valencia, Spain)», Journal of Archaeological Science, no 10, 1983, p. 333-349.

Cammas C., « Approche micromorphologique de la stratigraphie urbaine à Lattes : premiers résultats», Lattara, no 7, 1994, p. 181-202.

Cammas C., « Les « terres noires » urbaines du Nord de la France: première typologie pédo-sédimentaire », in Verslype L., Brulet R., Dark earth - Terres noires, Actes de la table ronde de Louvain-la-Neuve, Louvainla-Neuve, Université catholique de Louvain, 2004, p. 43-55.

Cammas C., Wattez J., « La micromorphologie : méthodes et applications aux stratigraphies archéologiques », in « La géologie » : les Sciences de la Terre appliquées à l’Archéologie, Paris, Errance, 2009, p. 181-218.

Cammas C., Champagne F., David C., Desachy B., Guyard L., « Le problème des « terres noires » sur les sites urbains tardo-antiques et médiévaux: reflexions et propositions méthodologiques à partir de l’exemple du Collège de France à Paris », Les Nouvelles de l’Archéologie, no 61, 1995, p. 22-29.

Cammas C., Courty M.-A., Fedoroff N., « Dynamique de la biostructuration dans les sols cumuliques, cas des terres noires de Paris », in Proceedings of the 16th World Congress of Soil Science (Montpellier, août 1998), International Society of Soil Science, natres.psu.ac.th/Link/SoilCongress/bdd/symp18/674-r.pdf, 1998.

Cammas C., Borderie Q., Augry S., Desachy B., « L’approche géoarchéologique de l’urbain. Développement du concept, méthodologie et application aux opérations archéologiques », Archéopages, no 31, 2011, p. 80-93.

CNAU, Fouille, enregistrement et analyse des fossés et de leur comblement en milieu urbain, Actes de la table ronde organisée au Centre National d’Archéologie Urbaine à Tours les 23 et 24 avril 1988, Tours, Ministère de la Culture et de la Communication, 1988.

CNAU, Centre National d’Archéologie Urbaine - Note sur le centre national d’archéologie urbaine par Desachy B., Paris, Sous-Direction de l’Archéologie, de l’Ethnologie, de l’Inventaire et du Système d’information, Département Recherche Méthodes Expertise, 2007.

Chaussée C., Allenet G., Girardclos O., Leroyer C., Pion P., Raymond P., «Holocene history of the River Seine, Paris, France: bio-chronostratigraphic and geomorphologic evidence from the quai Branly», The Holocene, no 18, 2009, p. 967-980.

Courty M.-A., Goldberg P., Macphail R. I., Soil and micromorphology in archaeology, New York, Cambridge University Press, 1989.

David C., « Les terres noires: outils méthodologiques, propositions analytiques et perspectives à partir de quelques exemples de sites à terres noires de l’Antiquité tardive et du haut Moyen Âge du nord de la France », in Verslype L., Brulet R., Dark earth - Terres noires, Actes de la table ronde de Louvain-la-Neuve, Louvain-la-Neuve, Université catholique de Louvain, 2004, p. 12-31.

Davidson D. A., Dercon G., Stewart M., Watson F., «The legacy of past urban waste disposal on local soils», Journal of Archaeological Science, no 33, 2006, p. 778-783.

Desachy B., « Terres noires du Collège de France, Paris: traitement par analyse factorielle des comptages en poids de fragments de matériaux de construction », in Terres noires 1, Documents Sciences de la Ville, no 6 (Juin 2000), Tours, 2000, p. 77-82.

Deschodt L., Sauvage L., « Cartes de formations superficielles et de potentiel archéologique: exemples dans le nord de la France », Cahiers de l’Inrap 2, 2008, p. 10-24.

Devos Y., Vrydaghs L., Degraeve A., Fechner K., «An archaeopedological and phytolitarian study of the “Dark Earth” on the site of Rue de Dinant (Brussels, Belgium)», Catena, no 78, 2009, p. 217-284.

Fondrillon M., La formation du sol urbain : étude archéologique des terres noires à Tours ( ive- xiie siècle), Thèse de doctorat, Histoire, Université François Rabelais, Tours, 2007.

Galinié H., « La question urbaine entre Antiquité et Moyen Âge », in Trente ans d’archéologie médiévale en France, Actes du IXe congrès international de la société d’archéologie médiévale, Caen, CRAHM, 2010, p. 337-350.

Gebhardt A., «Dark Earth: Some results in rescue archaeological context in France», in Macphail R. I., Acott T., Unpublished Bulletin 1 of the Archaeological Soil Micromorphology Working Group, Greenwich, University of Greenwich, 1997, p. 45-47.

Gébus L., Gama F., « Le quartier de la Pierre-Hardie et l’îlot Turmel dans la ville de Metz en Lorraine : deux exemples d’études archéologiques des couches sombres attribuées aux ive-xiie siècles », in Verslype L., Brulet R., Dark earth - Terres noires, Actes de la table ronde de Louvain-la-Neuve, Louvain-la-Neuve, Université catholique de Louvain, 2004, p. 135-144.

Golding K.A., The effect of waste disposal on soils in and around historic small towns, PhD Thesis, University of Stirling, 2008.

Guyard L. (dir.), Le Collège de France: du quartier Galloromain au Quartier latin ( ier s. av. J.-C.- xixe s.), Paris, Maison des Sciences de l’Homme, 2003.

Hall A.R., Kenward H.K., Environmental archaeology in the urban contexts, London, Council for British Archaeology, 1982.

Heimdhal J., Urbanized nature in the past. Site formation and environmental development in two Swedish towns AD 1200-1800’, thèse de doctorat, Géologie du Quaternaire, Université de Stockholm, 2005.

Jaffrot E., «Une étape de la recherche sur la relation entre l’usage du sol et l’état de conservation de la céramique domestique (du ier au xe s.)», Petits Cahiers d’Anatole, no 21, 2008.

Jouquand A.-M., Champagne F., Rodier X., Husi P., Wittmann A., « La fouille des “abords de la cathédrale” de Tours (Indre-et-Loire): Antiquité – haut Moyen Âge », Revue Archéologique du Centre de la France, no 38, 1999, p. 7-98.

Keene D.J., «Rubbish in Medieval towns», in Hall A.R., Kenward H.K., Environmental Archaeology in the Urban Contexts, London, Council for British Archaeology, 1982, p. 26-30.

Laurent C., « Études micro-archéologiques et carpologiques de sédiments sombres, à très sombres: arguments en faveur de l’extension chronologique de l’appellation terre noires », in Verslype L., Brulet R., Dark earth - Terres noires, Actes de la table ronde de Louvain-la-Neuve, Louvain-la-Neuve, Université catholique de Louvain, 2004, p. 56-74.

Leguay J.-P., « Le problème de l’évacuation des ordures au Moyen Âge : pérennité des usages antiques et nouveautés (ve-xve ap. J.-C.) », in Ballet P., Cordier P., Dieudonné-Glad N., La ville et ses déchets dans le monde romain : rebuts et recyclages, Actes du colloque de Poitiers, 19-21 septembre 2002, Montauban, Monique Mergoil, 2003, p. 303-311.

Macphail R.I., «Soil and botanical studies of the Dark Earth», in Jones M., Dimbleby G. W., The Environment of Man: The Iron Age to the Anglo-Saxon Period, Oxford, BAR British Series, no 87, 1981, p. 309-331.

Macphail R.I., «The Re-working of urban stratigraphy by human and natural processes», in Hall A.R., Kenward H.K., Environmental Archaeology in the Urban Contexts, London, Council for British Archaeology, 1982, p. 13-44.

Macphail R.I., «Soil microstratigraphy: a micromorphological and chemical approach», in Cowan C., Urban Development in North-West Roman Southwark: Excavations 1974-90, London, Museum of London Archaeology Service, 2003, p. 89-105.

Macphail R.I., «Dark earth and insights into changing land use of urban areas», in Sami D., Speed G., Debating Urbanism, within and beyond the Walls A. D. 300-700, Leicester, University of Leicester, 2010, p. 145-166.

Macphail R.I., «Soil micromorphology», in Fulford M., Rippon S., Pevensey Castle, Sussex. Excavations in the Roman Fort and Medieval Keep, 1993-95, Wessex Archaeology Report No. 26, Salisbury, Wessex Archaeology and University of Reading, 2011, p. 109-121.

Macphail R.I., Linderholm J., «Dark earth: recent studies of Dark earth and dark-earth-like microstratigraphy in England, UK», in Verslype L., Brulet R., Dark earth - Terres noires, Actes de la table ronde de Louvain-la-Neuve, Louvain-la-Neuve, Université catholique de Louvain, 2004, p. 35-42.

Macphail R.I., Crowther J., «Freeschool Lane and Vine Street, Leicester: soil micromorphology, chemistry and magnetic susceptibility», in Higgins T., Morris M., Stone D., Roman and Medieval Occupation within Leicester’s North-East Quarter: Excavations at Vine Street, Leicester (Highcross, Leicester) 2004 – 2006 SK 583 049, Unpublished report, Volume 2, Leicester, University of Leicester Archaeology Service, 2009, p. 507-527.

Macphail R.I., Goldberg P., «Archaeological Materials», in Stoops G., Mercelino V., Mees F., Interpretation of Micromorphological Features of Soil and Regolith, Amsterdam, Elsevier, 2010, p. 589-622.

Macphail R.I., Galinié H., Verhaeghe F., «A future for Dark Earth?», Antiquity, no 77, 2003, p. 349-358.

Macphail R.I., Crowther J., Cruise G.M., «Microstratigraphy», in Bateman N., Cowan C., Wroe-Brown R., London’s Roman Amphitheatre: Guildhall Yard, City of London, London, MoLAS Monograph, no 35, 2008, p. 16, 95, 160-164.

Marliac A., « Des terres noires urbaines aux buttes anthropiques tropicales : l’archéologue en action », L’Anthropologie, no 106, 2002, p. 745-761.

Matthews W., The micromorphology of occupational sequences and the use of space in a Sumerian city, Ph. D. thesis, University of Cambridge, 1992.

Matthews W., French C.A.I., Lawrence T., Cutler D.F., Jones M.K., «Microstratigraphic traces of site formation processes and human activities», World Archaeology, no 29, 1997, p. 281-308.

McGowan G., Prangnell J., «The signifiance of vivianite in archaeological settings», Geoarchaeology, no 21, 2006, p. 93-111.

Mikkelsen J.H., «Laboratory method for determination of organic, inorganic and total phosphate», in Bulletin of the Archaeological Micromorphology Working Group, mars 1997, table ronde I: Micromorphology and Phosphate, Gand, 1997.

Nicosia C., Langohr R., Mees F., Arnoldus-Huyzendveld A., Bruttini J., Cantini F., «Medieval Dark Earth in an active alluvial setting from the Uffizi Gallery complex in Florence», Geoarchaeology, no 27, 2012, p. 105-122.

Noizet H., «Fabrique urbaine: a new concept in urban history and morphology», Urban Morphology, no 13(1), 2009, p. 55-66.

Noizet H., Robert S., Mirlou L., « Cartographie des crues centennales à Paris (1740, 1910) », in Beck C., Franckhomme M., Guizard-Duchamp F., Heude J., Zones humides et villes d’hier et d’aujourd’hui: des premières cités aux fronts d’eau contemporains, Revue du Nord, hors série collection histoire, no 26, 2011, p. 91-104.

Rosen A.M., Cities of clay, the geoarchaeology of tells, Chicago, The University of Chicago Press, 1986.

Schwien J.-J., Schneider N., Watton M.-D., « Le site naturel de Strasbourg et ses aménagements hydrographiques de l’Antiquité à l’époque modern », Archéologie Médiévale, 28, 1998, p. 33-70.

Sidell E.J., «Dark Earth and obscured stratigraphy», in Huntley J.P., Stallibrass S., Taphonomy and Interpretation, Symposia of the Association for Environmental Archaeology, Oxford, Oxbow Books, 2000, p. 35-42.

Stoops G., Guidelines for analysis and interpretation of soil and regolith thin sections, Madison, Winsconsin, Soil Science Society of America, 2003.

Verslype L., Brulet R., Dark earth - Terres noires, Actes de la table ronde de Louvain-la-Neuve, Louvain-la-Neuve, Université catholique de Louvain, Centre de Recherches d’Archéologie Nationale, 2004.

Table des illustrations

Légende Fig. 1. Dark-Earth stratifications. A: Bayeux, rue Franche (photo: G. Schütz, 2010, Service Départemental d’Archéologie du Calvados). B: Beauvais, la Chapelle (photo: Q. Borderie, 2007). C: Metz, Sainte-Chrétienne (photo: S. Augry, 2008, Institut National de Recherches Archéologiques Préventives). D: Evreux (photo: B. Guillot, 2001, Institut National de Recherches Archéologiques Préventives).
URL http://books.openedition.org/editionscnrs/docannexe/image/22206/img-1.jpg
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Légende Fig. 2. Space functionalities, activities and formation processes of Dark Earth. Dark Earth are the result of complex formation processes, linked with environmental conditions (dry, wet, indoor, outdoor…) and, most of all, to activities and land use, as to their action to the soil/sediment. Thus, the functionalities of the spaces in which Dark Earth can be formed are often multiple and they can vary through time.
URL http://books.openedition.org/editionscnrs/docannexe/image/22206/img-2.jpg
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Légende Fig. 3. Examples of micro-elements in Dark Earth. Dark Earth contains many different micro-elements. Their combination and their state contribute to the identification of processes and activities taking part in the Dark Earth formation. A: Lead droplet embedded in calcitic ash (PPL, late Roman Dark Earth, Vine st. Leicester). B: As A but under oblique incident light showing black lead (centre), ‘red’ lead oxide (edge) and lead carbonate (contaminated ashes; Thilo Rehren, UCL, pers. com.). C: Vivianite cristal (Iron phosphate) in a bone pore (XPL, early Middle Ages, A. Briand pl. Noyon). D: As C but under PPL. E: Gypsum crystal (PPL, Sainte-Chrétienne Metz). F: Grapes seed (PPL, A. Briand pl. Noyon). G: Burned bone fragment on a thin calcitic ash layer (XPL, Grospiron sq. Noyon). H: As G but in PPL.
URL http://books.openedition.org/editionscnrs/docannexe/image/22206/img-3.jpg
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Légende Fig. 4. Organic carbon and calcium carbonate content in Dark Earth. The carbonated Dark Earth, on the right, is here all located in the Paris basin. Dark earth from Great Britain and Belgium are less carbonated. Organic carbon content is higher than 10 g/kg and can reach 25 g/kg. The strata underlaying the Dark Earth, which are Roman occupational layers or alluvial substrate, or earthworks, show lower amount of organic carbon. 1: Collège de France; 2: Metz Sainte-Chrétienne; 3: Beauvais Galerie nationale de la tapisserie; 4: Beauvais Cloître; 5: Beauvais Chapelle; 6: Noyon Evêché; 7: Bayeux Rue Franche; 8: Metz ZAC Amphithéâtre; 9: Noyon Square Grospiron; 10: London Ragoon st.; 11: London Southwark st.; 12: London Southwark Courage Brewery; 13: London Southwark Park st.; 14: London Jubilee Hall; 15: Florence Biblioteca; 16: Brussels Rue de Dinant; 17: Beauvais Galerie nationale de la tapisserie, earthwork; 18: Noyon Cloître cathédral, earthwork; 19: Metz Sainte-Chrétienne, Roman deposits; 20: Beauvais Chapelle, Roman pit filling; 21: Metz ZAC Amphithéâtre, alluvial substrate; 22: London Jubilee Hall, clay floor; 23: Florence Biblioteca, alluvial substrate; 24: Brussels Rue de Dinant. After Macphail, 1994; Cammas, 2004; Devos et al., 2009; Borderie, 2011b; Nicosia et al., 2012; Augry et al. Borderie, 2012.
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