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Dark earth is a thick, dark, urban sediment found between Roman and Medieval cultural layers of ancient urban settlements. Its study provides a means to understand early middle age societies and their relationship with urban spaces. The interpretation of these layers requires the use of detailed analysis primarily found within the discipline of Geoarchaeology. For this thesis, 20 stratigraphical layers (taken from Beauvais, Metz and Noyon) have been studied using geoarchaeological methods of analysis. Their study is based on an inventory of observations on dark earth compiled from five regions in the north of France (Haute -Normandie, Picardie, Île-de-France, Champagne-Ardenne and Lorraine). The research contained here demonstrates the high potential for the information contained within dark earth. Stratigraphical and latent feature analysis confirms the complexity of dark earth organisation. The physico-chemical characterisation of 89 stratigraphical units and the micromorphological analysis of 79 thin sections has both enabled the identification of the processes which led to the formation of dark earth and suggests the activities and urban, socio-spacial, practices which created them. This work also demonstrates the diversity of the material from which dark earth originates. This material is often in the form of small, regular, mixed deposits, and result from wastes from numerous activities, be they domestic or artisanal, or from re-reworked interior or external spaces. This research therefore brings substantial new information to the study of urban spaces between the Roman and Medieval periods and proposes an approach and ways of working in order to analyse the complexity of these spaces.; Les terres noires sont des sédiments urbains épais et sombres, situés entre les stratifications antiques et médiévales des anciennes agglomérations. Leur étude est un enjeu pour comprendre les sociétés du premier Moyen Âge et leurs pratiques des espaces urbains. L'interprétation de ces niveaux nécessite la mise en place d'études fines, recourant notamment à la géoarchéologie. En se fondant sur un inventaire des observations de terres noires, dans cinq régions du nord de la France (Haute-Normandie, Picardie, Île-de-France, Champagne-Ardenne et Lorraine), 20 stratifications de terres noires, réparties à Beauvais, Metz et Noyon, ont fait l'objet d'une approche géoarchéologique. L'important potentiel d'information contenu dans les terres noires a pu être démontré. La complexité de leur organisation a pu être soulignée, grâce à l'analyse stratigraphique et celle de leur structuration latente. La caractérisation physico-chimique de 89 unités stratigraphiques ainsi que l'analyse micromorphologique de 79 lames minces a permis d'identifier les processus à l'origine de la formation des terres noires et, au-delà, de proposer des activités et des pratiques socio-spatiales urbaines qui ont pu les créer. La diversité des apports à l'origine des terres noires a pu être mise en évidence. Ce sont souvent de petits dépôts rythmés et hétérogènes, pouvant correspondre à des rejets d'activités multiples, domestiques ou artisanales, ou parfois à des aménagements d'espaces intérieurs ou extérieurs. Cette recherche apporte donc des informations substantielles à l'étude des espaces urbains entre Antiquité et Moyen Âge et propose une approche et des pistes de travail pour en analyser la complexité.

O Brasil possui 58 meteoritos catalogados pela ciência meteorítica, número bastante inferior quando se compara tal número àqueles de países da Europa e aos de países como os Estados Unidos. As amostras estudadas pertencem à coleção de meteoritos do Museu de Mineralogia Professor Djalma Guimarães -MMPDG, constituída de 17 meteoritos, 10 brasileiros, entre eles o Bocaiúva e o João Pinheiro. O meteorito Bocaiúva, encontrado em MG, é o terceiro maior em peso do Estado (64kg), foi achado por volta de 1947, na cidade homônima, a 384km de Belo Horizonte. Além da massa principal do meteorito Bocaiúva, também há, no referido museu outro fragmento catalogado como "meteorito Bocaiúva", que, na verdade, é um fragmento pertencente a outro corpo meteorítico, o João Pinheiro, ainda não catalogado. A diferença mineralógica observada em ambos, principalmente com relação às porções silicáticas do Bocaiúva, assim como inclusões fluidas e fundidas, não deixa dúvida de se tratar de meteoritos diferentes. Minerais como kamacita, taenita, troilita, schreibersita e grafita são encontrados no meteorito João Pinheiro, enquanto que, no Bocaiúva, estão presentes a forsterita, kamacita, taenita, troilita, schreibersita, pentlandita, magnetita, cromita, pigeonita, diopsídio, enstatita, plagioclásios, apatita, calcita e goethita. Brazil has 58 cataloged meteorites for scientific studies; a low number compared to countries in Europe and the United States. The samples studied belong to a collection of 17 meteorites from the Mineralogy Museum Professor Djalma Guimarães - MMPDG in Belo Horizonte, Minas Gerais. Ten of those meteorites were found in Brazil; among them are the Bocaiúva and João Pinheiro meteorites. The Bocaiúva meteorite, the third heaviest (64kg), was found around 1947 in the town of Bocaiúva, located 384km from Belo Horizonte, in the state of Minas Gerais. Besides the Bocaiúva meteorite, there is also, in the MMPDG, another fragment cataloged as "Bocaiúva meteorite", which is actually a fragment from a different meteoritic body, called João Pinheiro, yet to be cataloged. The mineralogical differences, especially regarding the silicate portions of the Bocaiúva, as well as fluid and melted inclusions, leave no doubt that they belong to different meteorites. Minerals such as kamacite, taenita, troilite, schreibersita and graphite are found in the João Pinheiro meteorite, while in Bocaiúva are present forsterite, kamacite, taenita, troilite, schreibersite, pentlandita, magnetite, chromite, pigeonite, diopside, enstatite, plagioclase, apatite, calcite and goethite.

Several Archaeological Dark Earth (ADE) sites have been already found in the Colombian Amazon forest showing high content of archaeological ceramic fragments similarly to those in the Brazilian Amazon represented by Quebrada Tacana site. Their fragments are yellow to grey colour, display a burned clayey matrix which involves fragments of cariapé and coal and ash particles, besides grains of quartz and micas. The clay matrix is made of metakaolinite, quartz, and some mica flakes, chlorite and sepiolite. Cariapé and cauixi spicules are constituted of cristobalite, which is also the main mineral component of the coal and ashes. Although not detected by X-ray diffraction, the phosphate minerals should be present, since the contents of phosphor reach up to 2.90 Wt.% P2O5. Possibly it occurs as aluminium-phosphate, since Ca contents fall below 0.1 Wt.%. These mineralogical and chemical characteristics allow to correlate these ceramic fragments with those found in the ADE in Brazil and reinforce phosphor as an important chemical component, which indicates human activity by the daily use of pottery all over the Amazon region. Vários sítios arqueológicos de Terra Preta Arqueológica (TPA) encontrados na floresta Amazônica Colombiana também contêm alto conteúdo de fragmentos cerâmicos semelhantes aqueles da Amazônia Brasileira, como mostra o sítio Quebrada Tacana. Seus fragmentos cerâmicos são amarelo a cinza, exibem matriz argilosa calcinada envolvendo fragmentos de cariapé, carvão e partículas de cinza, grãos de quartzo e micas. A matriz é composta de metacaulinita a material amorfo, quartzo, folhas de micas, clorita e sepiolita. Cariapé e cauixi são constituídos de cristobalita, da mesma forma o carvão e as cinzas. Embora não detectados pela difração de raios x, os fosfatos devem estar presentes, pois foram detectados teores de P2O5 de até 2,90 %, possivelmente como fosfatos de alumínio, já que o conteúdo de Ca está abaixo 0,1 %, o que elimina a possibilidade da presença de apatita. Estas características mineralógicas e químicas permitem relacionar estes fragmentos cerâmicos com aqueles encontrados nos sítios de TPA no Brasil e reforça o fósforo como um importante componente químico, originado pelo contato dos vasos cerâmicos com os alimentos do cotidiano dos povos amazônicos pré-históricos.

Vários sítios arqueológicos de Terra Preta Arqueológica (TPA) encontrados na floresta Amazônica Colombiana também contêm alto conteúdo de fragmentos cerâmicos semelhantes aqueles da Amazônia Brasileira, como mostra o sítio Quebrada Tacana. Seus fragmentos cerâmicos são amarelo a cinza, exibem matriz argilosa calcinada envolvendo fragmentos de cariapé, carvão e partículas de cinza, grãos de quartzo e micas. A matriz é composta de metacaulinita a material amorfo, quartzo, folhas de micas, clorita e sepiolita. Cariapé e cauixi são constituídos de cristobalita, da mesma forma o carvão e as cinzas. Embora não detectados pela difração de raios x, os fosfatos devem estar presentes, pois foram detectados teores de P2O5 de até 2,90 %, possivelmente como fosfatos de alumínio, já que o conteúdo de Ca está abaixo 0,1 %, o que elimina a possibilidade da presença de apatita. Estas características mineralógicas e químicas permitem relacionar estes fragmentos cerâmicos com aqueles encontrados nos sítios de TPA no Brasil e reforça o fósforo como um importante componente químico, originado pelo contato dos vasos cerâmicos com os alimentos do cotidiano dos povos amazônicos pré-históricos. Several Archaeological Dark Earth (ADE) sites have been already found in the Colombian Amazon forest showing high content of archaeological ceramic fragments similarly to those in the Brazilian Amazon represented by Quebrada Tacana site. Their fragments are yellow to grey colour, display a burned clayey matrix which involves fragments of cariapé and coal and ash particles, besides grains of quartz and micas. The clay matrix is made of metakaolinite, quartz, and some mica flakes, chlorite and sepiolite. Cariapé and cauixi spicules are constituted of cristobalite, which is also the main mineral component of the coal and ashes. Although not detected by X-ray diffraction, the phosphate minerals should be present, since the contents of phosphor reach up to 2.90 Wt.% P2O5. Possibly it occurs as aluminium-phosphate, since Ca contents fall below 0.1 Wt.%. These mineralogical and chemical characteristics allow to correlate these ceramic fragments with those found in the ADE in Brazil and reinforce phosphor as an important chemical component, which indicates human activity by the daily use of pottery all over the Amazon region.

The early developments of Antwerp are still poorly understood. Archaeological excavations and historical sources report the presence of a 9th century AD settlement, the core for further development of medieval Antwerp in the neighbourhood of the river Scheldt, the so-called Burchtsite. New excavations took place between July 2008 and April 2009. Archaeologists discovered structures of a 9th to 11th century AD portus and early town, surrounded by an urban rampart. The settlement seems comparable with contemporary early towns such as Haithabu. Under the 9th century structures, humus-rich, non-peaty, strongly melanised and apparently homogeneous units, known as Dark Earth have been encountered. This Dark Earth was found to cover Roman traces. By applying micromorphological research to this seemingly homogeneous Dark Earth, we hope to come to a better understanding of the formation processes of the Dark Earth and to identify traces of human activities hidden within the Dark Earth. As such, we hope to enhance our understanding of the activities, environment and spatial structure of the early medieval phase of this town.

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Description and morphologic characterization; Extraction, chemical fractionation and purification of the humic material; DRIFT Spectroscopy analysis.

During the excavations of the site of Rue de Dinant in the historic centre of Brussels (Belgium), remains of the first city wall dating from the 13th century have been discovered. Intra muros thick dark sediment units predating this wall are observed. These dark units are among the oldest occupation traces so far encountered in this higher, eastern, part of the historic centre of Brussels. In order to characterise them, and to understand the human activities and natural processes behind their formation, an interdisciplinary research, integrating archaeopedology and phytolith study, has been undertaken. This approach permitted us to identify a range of natural and cultural processes leading to the formation of these dark layers, and to characterise different activities. Remains of a hearth, old plough land (cropfields) and grassland have been identified, all activities referring to a rural landscape organisation. Later on, the area changes into an enormous silt extraction area, whereby Dark Earth is thrown into the dug pits. Finally, the construction of the first city wall marks the area as becoming part of the city. The study of Dark Earth shows to be a potentially valuable tool to shed light on the development and spatial organisation of pre-urban Brussels, a historically very poorly documented period.

For many decades, archaeologists working in Amazonia have looked for terra preta (black soil) areas in their search for ancient settlements. The typical Amazonian archaeological site is comprised of a combination of black soil, ceramic sherds and some distinct vegetation species, which William Balee calls “cultural forests” (Balee 1989). Sites are usually located in elevated terrains or riverine bluffs, protected from the annual floods when along the major rivers floodplains. Archaeologists also know that there is some correlation between soil color and density of ceramic sherds, both being a sensor for ancient demography patterns. Ever since Sombroek (1966) and Smith and Nigel (1980) reported the existence of the anthropogenic terra preta soils, and especially after several research projects carried out by soil scientists and archaeologists during the last 20 years, research on ADE (Amazonian Dark Earth) sites has drawn much scientific interest. Analysis of ADE samples have demonstrated that such soils present higher levels of chemical nutrients such as C (carbon), P (phosphorus), Ca (calcium), Mg (magnesium), Zn (zinc) and Mn (manganese) when compared to original, background soils, besides presenting superior pH, as well as higher amounts of organic material, which make them particularly fertile (Kern and Kampf 1989; Kern et al. 1999; McCann et al. 2000). Such elements were possibly added to the soils during degradation of organic debris related to human occupation and discarding activities (Eidt 1985; Kern, et al. 1999; Woods and McCann 1999; McCann et al. 2000). High values of P, Ca and Mg on ADEs can be attributed in part to animal residues, since bones, blood, carapaces and feces are rich in these elements. Zn and Mn might occur as residues of palm trees, whose leaves are commonly employed as construction material for house walls and roofs, beds, hammocks, and basketry (Kern et al. 1999). Soil chemistry studies directed to solve archaeological problems have increased in number in the last three decades. While physical modifications caused by anthropic factors, such as sediment compression and texture changes can be perceived by an experienced archaeologist, chemistry, although less evident to the naked eye, can contribute to determine boundaries of activity areas, and help to define stratigraphy and function of an archaeological site (Woods 1984). Chemical anomalies coupled to

The anthropogenic addition of organic amendments, including plant and animal material, pottery, and charcoal, into extant soil formed what are known as Terra Preta do Indio (TPI) or Amazonian Dark Earth (ADE). Whether or not these soil amendments were part of an agricultural management strategy by pre-Colombian cultures, today ADE soils are prized by farmers for their sustained fertility, in regions where chronic soil infertility has lead, in part, to on-going destruction of primary forest to create marginal cropland. However, although prehistoric practices have left a legacy of fertile soil for a few isolated farmers, expanding the benefits of ADE to other soils will require more than serendipity. The unusual chemistry resulting from organic amendments to ADE results in distinct microbial communities that are involved in nutrient cycling and ecological processes. The ongoing biogeochemical activity in ADE is the true legacy of prehistoric practices, and the microbial processes at work in these unique soils are crucial to these

Biochar, when placed in soil, greatly improves the soil — leading to much improved productivity, as well as a reduced need for fertilizers. Such biochar also removes carbon dioxide from the atmosphere — perhaps for millenia, and this form of carbon sequestration may be cheaper than by any other means. The millenia claim is based on experience with ancient Amazonian “terra preta” (dark earth) soils. When the biochar is produced, one hopes for a high-value use for the accompanying pyrolysis gases. Two such early high-value applications are the sugar refining industry and charcoal-making (not charcoal-using) cook-stoves. At this time, there is no accepted methodology for providing carbon credits for these potentially huge triple (energy-atmosphere-soil) benefits. Emphasis below is on commercialization status, building on its importance to rural societies. This paper expands on the author’s first biochar paper from ten months earlier, during which time much has happened.

Soils and archaeology as a subject developed during the 1950s and 1960s when the effects of humans on natural soils were first investigated. This was carried out using soil profile description and standard soil science techniques. During the following years, soil phosphate as a specific analytical technique came to prominence alongside such studies as mineral magnetics, particularly magnetic susceptibility (sometimes termed χ), and landscape-scale investigations commenced. It can be noted that soil micromorphology applied to archaeology also has a very long pedigree. This article briefly examines the history of soils and archaeology, describes some of the techniques that have been the most rewarding, and details some of the progress that has been made over the last 50 years, including experiments. Archaeological soils and associated sediments are categorized in terms of the impact humans have had on them. This article thus progresses from the basics of soils that show – compared with ‘control soils’ (see below) – a small amount of human impact, to soils that are strongly influenced by humans and their occupation.

Fifth-century evidence exists in diverse forms in different places and the varying survival of data itself indicates how well a region weathered the storms of the century. The bulk of the written material comes from southern Gaul, Italy, Africa and to a lesser extent Spain. Northern Gaul and Britain, however, are more or less documentary blanks. The visibility of archaeological evidence tends to follow the same pattern, although the quality of investigation has until recently not been very even. This only underlines the point. Significant traces of fifth-century settlement have been found in those areas that produced the bulk of the written data, even when the theory and practice of excavation remained elementary. On the other hand, where the documentary record is sparsest the archaeological evidence has been the most intractable. In Britain, for example, a considerable corpus of such material exists, but it has required much greater technical expertise for its recovery. The nature and survival of evidence are not haphazard but speak eloquently about the diverse experiences of the fall of Rome. THE MATERIAL BASE: SOCIETY AND ECONOMY Africa From the end of the fourth century and the beginning of the fifth, North African towns underwent significant changes, not least in the use of public space. Many fora were abandoned or given over to new uses. In Belalis Maior (Henchir el-Fouar) a dirt layer, with some burials, covered the forum while that at Bulla Regia (Hammam Derradj, Tunisia) also fell into disrepair, although other public buildings continued in use.

This research is dealing with archaeological and geo-archaeological studies which, for thirty years in northern Europe, have partly renewed our understanding of medieval towns by analyzing dark earth layers. Not yet considered enough, this kind of deposit represents however an important historical record of ancient roman cities.The study lay out both methodological and analytical interest. A method of creating and studying samples is explored, especially for archaeological stratifications in urban context. Experiences have been led on five excavations at Tours by analyzing fine and coarse composition of urban layers. The study is based on the principle that human activities are recorded in archaeological deposits. By applying site formation processes, developed for a long time in prehistoric and geoarchaeological researches, and by creating functional classification, the study allows characterization of human behavior which produced urban strata.At the scale of archaeological sites, dark earth deposits attest specific activities: cultivated plots, domestic areas with ground refuse, open spaces and retrieval activities of construction elements have been identified. The study shows that dark earth deposits, which look like homogeneous soil layers, result in fact from diverse urban activities, which have been partly cancelled by post depositional processes.At the scale of towns, dark earth produces evidence for cultural changes in urban lad-use. This study, integrated into urban archeological research developed since 1990's, contributes to a survey of new social practices of urban space from Late Antiquity, revealing new ways of constructing and living compared to classical towns.; Cette étude s'inscrit dans le courant des études archéologiques et géoarchéologiques qui, depuis une trentaine d'années en Europe du Nord-Ouest, ont permis de renouveler une partie des connaissances sur la ville du haut Moyen Âge par l'analyse des terres noires urbaines. Encore trop peu considérées aujourd'hui, ces dernières représentent pourtant une archive de l'histoire des villes d'origine antique.L'étude présente un intérêt méthodologique et analytique. Elle propose une méthode d'acquisition et de traitement des données spécifique aux stratifications archéologiques en contexte historique. L'expérience a été menée sur cinq sites archéologiques à Tours (Indre-et-Loire), en considérant la composition sédimentaire, grossière et fine, des dépôts mis au jour. Cette analyse repose sur le postulat que les traces des activités humaines sont enregistrées dans la composition sédimentaire des couches archéologiques. Par l'application des principes de formation des stratifications, développés initialement par les préhistoriens et les géologues, l'étude permet de caractériser les usages anthropiques à l'origine de ces séquences urbaines, après avoir mis en place un référentiel fonctionnel de couches archéologiques fondé sur des critères discriminants.À l'échelle du site, les séquences de terres noires étudiées témoignent d'activités spécifiques et variées : ont ainsi été mis en lumière des parcelles cultivées, des zones d'habitat et de rejets domestiques, des espaces extérieurs occupés ou encore des activités de récupération de matériaux de construction. Les résultats montrent que ces séquences, en apparence non stratifiées, ont été produites par des activités humaines diversifiées, que les processus post-dépositionnels ont le plus souvent oblitérées.À l'échelle de la ville, les terres noires attestent les changements progressifs qui affectent les rapports des habitants à la ville. Ainsi cette étude, intégrée aux recherches urbaines développées depuis les années 1990, contribue à la reconnaissance de nouvelles pratiques sociales de l'espace urbain à partir du Bas-Empire, témoignant de nouveaux modes d'occuper, d'habiter, de construire.

Terra Preta soils of central Amazonia exhibit approximately three times more soil organic matter, nitrogen and phosphorus and 70 times more charcoal compared to adjacent infertile soils. The Terra Preta soils were generated by pre-Columbian native populations by chance or intentionally adding large amounts of charred residues (charcoal), organic wastes, excrements and bones. In this paper, it is argued that generating new Terra Preta sites (‘Terra Preta nova’) could be the basis for sustainable agriculture in the twenty-first century to produce food for billions of people, and could lead to attaining three Millennium Development Goals: (i) to combat desertification, (ii) to sequester atmospheric CO2in the long term, and (iii) to maintain biodiversity hotspots such as tropical rainforests. Therefore, large-scale generation and utilization of Terra Preta soils would decrease the pressure on primary forests that are being extensively cleared for agricultural use with only limited fertility and sustainability and, hence, only providing a limited time for cropping. This would maintain biodiversity while mitigating both land degradation and climate change. However, it should not be overlooked that the infertility of most tropical soils (and associated low population density) is what could have prevented tropical forests undergoing large-scale clearance for agriculture. Increased fertility may increase the populations supported by shifting cultivation, thereby maintaining and increasing pressure on forests.

Os solos da Amazônia que possuem horizonte A antrópico (Au) apresentam elevada fertilidade natural geralmente atribuída ao teor elevado de matéria orgânica e à sua elevada reatividade. Neste estudo foram quantificadas as substâncias húmicas e caracterizados os ácidos húmicos (AH) extraídos da camada 0-20 cm de solos com horizonte Au do estado do Amazonas (Terra Preta de Índio) sob floresta e cultivo agrícola. Também foram investigadas amostras de solos adjacentes sem o horizonte antrópico. A caracterização dos AH foi realizada através de análise termogravimétrica, análise da composição elementar e quantificação dos grupos funcionais (total, carboxílica e fenólica). Os horizontes A de solos antropogênicos apresentaram maior teor de carbono total, comparados aos de solos adjacentes. Entre as frações húmicas, a mais abundante foi a humina. A fração de ácidos húmicos (AH) foi a dominante das frações alcalino-solúveis nos solos estudados. Os AH dos solos antropogênicos tanto sob floresta como sob cultivo agrícola apresentaram maior grau de humificação quando comparados aos AH dos solos sem o horizonte Au. O cultivo agrícola também teve efeito na estabilidade e reatividade dos AH nos solos antropogênicos. Amazonian dark earth soils that have anthropogenic A horizon (Au) present high natural fertility usually attributed to their high organic matter content and to their higher reactivity. In this study humic substances were quantified and the humic acids (HA) extracted from the 0-20 cm layer of Amazonian dark earth soils (Terra Preta do Índio) under forest and agricultural use were characterized. Adjacent soils with no Au horizon were also investigated. The HA were characterized through the thermogravimetric analysis, elemental composition analysis and characterization of functional groups (total, carboxylic, and phenolic). The A horizon of the anthropogenic soils presented higher total carbon level compared to adjacent soils. Among the humic fractions, the humin was the most abundant. The humic acid fraction (HA) was the dominant among the alkaline soluble fractions. The humic acids of the anthropogenic soils, both under forest and cultivation, showed higher humification degree compared to the non-anthropogenic soils. The agricultural cultivation affected the humic acids stability and reactivity in the anthropogenic soils.