Palaeoenvironmental research
in archaeological contexts
The actual palaeoenvironmental research conducted at the CReA is the continuation of the activities realised since 1992 at the ULB by the ‘Unité de Recherches en Archéozoologie et Paléoenvironnement’ and later the ‘Groupe interdisciplinaire d’Etudes du Paléoenvironnement’ through conventions and orders granted by the Walloon Region and the Brussels Capital Region, as well as by several French organisms. Archaeopedological, archaeobotanical and microarchaeological, as well as archaeozoological studies have been realised on archaeological sites of all periods.
Today, the palaeoenvironmental centre focusses on archaeopedological, microarchaeological and carpological studies.
Major research subjects :
Food in the past
The oldest data concerning the vegetable human diet, so far recovered during palaeoenvironmental studies on TGV (High Speed Train) archaeological survey in Wallonia, are from Neolithic sites : Remicourt « Fond de Momalle » (Liège), Fexhe-le-Haut-Clocher « Podrî l’Cortri » nord (Liège), Fexhe-le-Haut-Clocher « Voroux Goreux » (Liège) and Ath / Ormeignies « Pilori » (Hainaut).
The oldest carpological remains are all carbonised. This is not a surprise, as carbonisation is one of the best ways to conserve this type of elements.
From the Metal Ages onwards, the vegetable feeding is better documented. This is not only due to the increasing number of studied sites - Orp-Jauche / Maret « Le Tierceau » (Brabant), Hélécine « Chapeauveau » (Brabant), Remicourt / Bergilers « Fond de Lantremange » (Liège) , Ath « Bois du Jardin » (Hainaut) and Leuze-en-Hainaut / Tourpes « Fraide Berte » (Hainaut) – but also due to an increasing number of cultivated species. And, of course, the fact these remains are more recent allows a better conservation. The collected data show a diversification of the cultures.
Most of the cereal species remain, with some proportional variations, until Modern Times.
It is also on Roman sites - Waremme « Quatre-Abias » (Liège) and Fexhe-le-Haut-Clocher « Petite Campagne » (Liège) – that the first carbonised residues of cereal food preparation (bread, gruel…), as well as consumed roots are recovered. Remains of food preparation based on cereals, roots and fruits are extremely rare in archaeological sediments. Therefore we can only find them as millimetric fragments.
The development of a research protocol for microarchaeological investigations allows the discovery of this kind of millimetric features. It also forms a link between micromorphology and the classical archaeological studies.
Animal fodder can also be identified, like for example on the sites of Brunehaut / Jollain Merlin (Hainaut) and Mouscron / Dottignies « Cora » (Hainaut). Numerous coprolites have shown crushed mineralised herbs and seeds from wet meadows and fenlands. They give us information about the possible presence of stabling areas as well as on the local vegetation of the grazing zones. In urban sites, human and animal coprolites are often mixed. This confirms the close relationship between man and animals in such contexts.
Carpological studies for the Early Middle Ages are rare. Nevertheless, fruit cultivation seems to persist.
From urban contexts - Huy « rue sous-le-château » (Liège), Liège « esplanade St. Léonard », and several sites in Brussels- the fruit cultivation, especially viticulture, and the spice and condiment’s use, becomes clearly more important and more varied during the Late Middle Ages.
Based on carpological remains only, it is not always possible to be sure of the kind of use made of the different plants species. Very few species are used for textile fabrication in our countries. For dyeing, almost every species can offer some colouring stuff, more or less powerful according to the parts of the plant used, to the kind of fibres on which the colour is applied (wool, hemp, linen, leather…) and to the possible use of a mordant as catalytic. Because of the almost unlimited number of combinations, an interpretation based on the confrontation of all the available data (botanical, chemical, archaeological…) is highly recommended.
On the site of Orp-Jauche / Maret « Le Tierceau » (Brabant), several species which might have been used for textile fabrication were identified. This is of course not the only case, but here, we have weaving material in the neighbourhood, and the textile species’ remains found are concentrated in the filling of two structures that are associated with mineralised macro remains of plants which might have been used for the coloration of textiles. This mineralization might result of the use of a mineral catalytic in order to obtain a better fixation of the colouring agents. Nevertheless, more thorough analyses are needed to prove the presence of this particular activity on the site.
Hôtel de Lalaing Hoogstraeten. The different occupation phases are reflected in the complex stratigraphy. (1 and 2 : 11th-13th century plough horizons ; 3 and 4 : waste deposits ; 5 and 6 : 16th-17th century gardening horizons)
Localisation of the archaeological sites
1 : Treurenberg
2 : Hôtel de Lalaing-Hoogstraeten
3 : rue d’Une Personne
4 : place de la Vieille-Halle-aux-Blés
5 : impasse du Papier
6 : rue de Dinant
During the excavations in the historical centre of Brussels, archaeologists are often faced with metres of complex stratigraphy of soils and sediments, revealing the origins and the development of Brussels.
These soils and sediments protect not only the archaeological objects; they can also preserve soil features witnessing ancient human activities. Examples are trampling features, ard marks and plough marks. Archaeopedological studies enable to identify and to characterise these features. They also allow the understanding of the direct and indirect effects of other human activities, like forest clearing, cultivation, the implantation of houses and mining, on the environment. Moreover, archaeopedological studies permit to detect evidences of catastrophes like landslides, inundations or soil pollution.
The preparation and the cultivation of soils, and the first developments of Brussels are a first major archaeopedological research theme.
The study of the Treurenberg site demonstrated the presence of a small ancient open air stone quarry, preceding the 11th century field. The archaeopedological field study on the site of the Rue de Dinant, allowed the identification of large pits, which seem to be filled with several types of fragments shortly after the digging of the pits. These pits, reaching the base of the silty sediments, might have been used for the extraction of these silts. The archaeological remains collected in the fill point also the 11th-12th century AD as terminus ante quem.
Several horizons that can also illustrate these first phases of the history of Brussels, have been identified during excavations in the city-centre (Treurenberg, Hôtel de Lalaing-Hoogstraeten, impasse du Papier, place de la Vieille-Halle-aux-Blés and rue de Dinant). These horizons are dark, homogeneous, humiferous, with a abrupt horizontal lower boundary (Ill. 8). C-14 dating places them between the 11th and the 13th century AD. Archaeopedological field observations, as well as laboratory analyses (essentially micromorphology, chemical and physical analyses) (Ill. 9), allowed the identification of these horizons as plough horizons and thus testifying of ancient agricultural practices. The conducted interdisciplinary study, involving archaeobotany (carpology, anthracology and the study of phytoliths) and micro-archaeology, has allowed the identification of several cereals (avena sp., triticum sp. and hordeum sp.), as well as the application of manure and the liming of the naturally poor soil.
The identification of these arable fields, especially underneath the first city wall (the sites of the Treurenberg and rue de Dinant), confirm the rural character of Brussels in this historic poorly documented period. Moreover, the palaeoenvironmental research informs us about ancient agricultural practices and diet.
The second theme of archaeopedological research concerns the ancient (pre-industrial) pollution in Brussels.
Hôtel de Lalaing-Hoogstraeten : detail of the plough horizons
During the growth of Brussels, human activities have had effects that can be felt even today. The profound changes in the landscape, for instance, can still be witnessed. Less visible are the accumulations of ancient pollution in the historical town centre.
However, ancient texts mention repeatedly nuisances caused by several artisanal activities, as well as by the presence of all kind of waste deposits. Unfortunately, these sources do not provide reliable data on the importance of the different kinds of pollution.
Rue d’Une Personne : photo showing the presence of waste deposits. The micromorphological study demonstrated the presence of vivianite (iron-phosphate) and pyrite. These minerals are formed during the slow decomposition of the organic waste. The presence of jarosite, which has been formed once the pyrite has been oxidised, is indicative for the acidification of the soil.