Tag Archives: expérimentation

2014-04–HENRY-THERY

FUEL USE AND MANAGEMENT DURING THE MESOLITHIC:

Recent Approaches in Archaeobotany

Auréade HENRY, Isabelle THÉRY-PARISOT

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Abstract

In order to propose working models for the Mesolithic period, this paper presents recent developments in archaeobotany orientated towards the question of fuel management systems and how ethnographic studies and experimentation can enhance our understanding of past phenomena.
The importance of fire and its systematic use during the Mesolithic can be assessed through direct evidence, i.e. the recovery of burned materials with wood, stone, bone and plant remains being the most commonly encountered. The diversity of activities related to fire is also suggested by indirect testimonies, such as the presence of materials (or their processing traces on artefacts) for the production of which a thermic treatment is needed, such as birch tar, animal hides, etc.
 In accordance with these observations, fuel management practices of Mesolithic societies were undoubtedly complex and culturally significant. However, they remain difficult to approach archaeologically: What kind of fuel was collected and for which purposes? What is the relationship between environment, fuel selection, hearth and site functions?

To cite this article

Henry A., Théry-Parisot I., 2014 – Fuel Use and Management during the Mesolithic: Recent Approaches in Archaeobotany, in Henry A., Marquebielle B., Chesnaux L., Michel S. (eds.), Techniques and Territories: New Insights into Mesolithic Cultures, Proceedings of the Round table, November 22-23 2012, Maison de la recherche, Toulouse (France), P@lethnology, 6, 65-83.

2010-06–RUAS-BOUBY

Carbonization, preservation
and deformation of carpological remains

Marie-Pierre RUAS, Laurent BOUBY

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Abstract

In archaeological sites in temperate climates and with aerobic conditions, carbonized seeds represent the majority of preserved carpological remains. Among these, cereals, legumes and certain fruits are the most frequent. In this paper, we present a selection of experiments concerning the effects of carbonization on the deformation of seeds and fruits and on the differential preservation of carpological assemblages. These experiments explored the influence of parameters such as temperature, heating duration, oxidizing or reducing conditions and the initial state of the seeds in on the modifications of their forms and dimensions.They were conducted on hulled or naked caryopses, seeds of pea, apple and wild and cultivated grape seeds. Other experiments focused on the rapidity of destruction of the anatomical parts of ripe cereals (stem, rachis, glumes, caryopses) and acorns (casings, pericarps, cotyledons), and of the seeds of various wild or cultivated plants according to their physical and biological constitution. The results allow us to evaluate the taphonomic biases created by carbonization, which are detrimental to the specific identification of seeds and the interpretation of archaeological assemblages.

To cite this article

Ruas M.-P., Bouby L., 2010 – Carbonization, Preservation and Deformation of Carpological Remains, in Théry-Parisot I., Chabal L., Costamagno S., The taphonomy of Burned Organic Residues and Combustion Features in Archaeological Contexts, Proceedings of the round table, May 27-29 2008, CEPAM, P@lethnology, 2, 69-78.

2010-07–THÉRY-PARISOT-ET-ALII

From wood to wood charcoal:

an Experimental Approach to Combustion

Isabelle THÉRY-PARISOT, Lucie CHABAL,
Maria NTINOU, Laurent BOUBY, Alain CARRÉ

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Abstract

The anthracological deposit as it appears in archaeological contexts is the result of successive taphonomic agents intervening at many stages from the gathering of wood, to combustion and post-depositional processes. These taphonomic agents constitute successive filters between the past vegetation and the charcoal studied. Therefore, the interpretation of charcoal remains should take into account the potential deformation between the anthracological spectra and initially burned wood.

This paper presents the methodological issues and the first results of an experimental cycle whose aim was to study one of these taphonomic agents: the combustion process. Does combustion involve differential preservation of burned wood species? Does charcoal quantification reflect the real proportion of burned species? Is it necessary to define a correctional index for anthracological data?

In order to answer these questions, 110 experiments were carried out under standardized laboratory conditions and more than 295000 charcoals were studied. Such factors as wood density or temperatures are often considered to play an active role in the fragmentation process of charcoal during combustion. As expected, the results indicate a differential behaviour of species, but one which proved to be independent of the expected factors, tending to show that the parameters that interact in the combustion process are of different nature. These factors increase the difficulty of defining a correctional index. Nevertheless, it seems that the quantification of charcoal reflects in a satisfactory manner the initial proportion of each of the burned species.

To cite this article

Théry-Parisot I., Chabal L., Ntinou M., Bouby L., Carré A., 2010 – From Wood to Wood Charcoal: an Experimental Approach to Combustion, in Théry-Parisot I., Chabal L., Costamagno S., The taphonomy of Burned Organic Residues and Combustion Features in Archaeological Contexts, Proceedings of the round table, May 27-29 2008, CEPAM, P@lethnology, 2, 79-91.

2010-08–DELHON

Phytoliths and taphonomy

the Contribution of Experimentation
to the Quantification of Phytoliths in Wood Ashes

Claire DELHON

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Abstract

Ashes, the mineral residues of wood combustion, contain siliceous particles that can be preserved for long periods in archaeological sediments. Phytoliths can thus be useful indicators of combustion activities whose biodegradable or soluble remains have disappeared.
In this paper, an experimental evaluation of the potential of phytoliths for the quantitative and qualitative analysis of carbonized ligneous biomasses is presented. The results show: 1) that only a very small portion of ash is capable of resisting dissolution phenomena, 2) that phytoliths originating from ligneous tissues are only slightly characteristic from a taxonomic perspective, and 3) that it is not possible through a routine microscopic analysis to differentiate phytoliths derived from combustion and phytoliths liberated following a slow decomposition of organic material. It thus appears that strong concentrations of “wood” phytoliths can be an indicator of combustion, but that phytolithic analysis does not allow taxonomic identification of the ligneous combustible or evaluation of the quantity of biomass burned.

To cite this article

Delhon C., 2010 – Phytoliths and Taphonomy, the Contribution of Experimentation to the Quantification of Phytoliths in Wood Ashes, in Théry-Parisot I., Chabal L., Costamagno S., The taphonomy of Burned Organic Residues and Combustion Features in Archaeological Contexts, Proceedings of the round table, May 27-29 2008, CEPAM, P@lethnology, 2, 93-104.

2010-14–COSTAMAGNO-ET-ALII

Taphonomic impact of prolonged combustion
on bones used as fuel

Sandrine COSTAMAGNO, Isabelle THÉRY-PARISOT,
Delphine KUNTZ, François BON, Romain MENSAN

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Abstract

The combustion of bones results in numerous processes whose impact on the representivity of fossil bone assemblages is increasingly well known due to the multiple experimental approaches developed over the last ten years. Recent experiments conducted with outdoor hearths have shown the consequences of prolonged combustion on bone combustion residues.

The average loss of bone mass after combustion is 65 %. The weight of the fine fraction (ashes and fragments less than 2 cm) corresponds to more than one quarter of the residual mass of the remains collected, while the mass of calcined (i.e. white) bone represents an average of 77.2 % of the residues. Finally, the residual bone mass is not correlated with the duration of use of a hearth, but with the manner in which it is maintained. These experiments thus clearly document the significant role of fire maintenance methods on the nature and form of bone residues.

To cite this article

Costamagno S., Théry-Parisot I., Kuntz D., Bon F., Mensan R., 2010 – Taphonomic Impact of Prolonged Combustion on Bones Used as Fuel, in Théry-Parisot I., Chabal L., Costamagno S., The taphonomy of Burned Organic Residues and Combustion Features in Archaeological Contexts, Proceedings of the round table, May 27-29 2008, CEPAM, P@lethnology, 2, 169-183.

2010-15–GERBE

The action of weathering on burned bone:

an Experimental Approach

Magali GERBE

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Abstract

The alteration of bones following exposure to weathering is today well known, but it is possible that burned bones do not suffer the same type of changes since their physicochemical properties are modified by combustion. A series of experiments has been carried out with the aim of better understanding these reactions. These experiments form part of a more widespread attempt to better understand the impact of taphonomic agents on burned bones in order to estimate the distortions between bone material originating from experimental combustion and the fossil material.

Five experimental series resulting from the combustion of fresh cow humeri were exposed for eighteen months to weathering in a Mediterranean context. Several criteria were observed in order to highlight the impact of this exposure on the burned bones: degree of fragmentation, loss of bone mass, alteration of bone surface, influence of the degree of combustion (carbonised vs charred) and of the bone tissue (spongy vs compact) on the preservation of the material.

The results of these experiments mainly show a high fragmentation of the material (the small burned bones being in the majority), associated with a reduction in bone mass. In addition, spongy and charred bones have an increased sensitivity to the action of weathering, leading to their destruction. A preferential preservation of charred compact bone is thus expected.

To cite this article

Gerbe M., 2010 – The Action of Weathering on Burned Bone: an Experimental Approach, in Théry-Parisot I., Chabal L., Costamagno S., The taphonomy of Burned Organic Residues and Combustion Features in Archaeological Contexts, Actes de la table ronde, 27-29 mai 2008, CEPAM, P@lethnology, 2, 185-196.

2009-06–CHESNAUX

Sauveterrian microliths:

Evidence of the Hunting Weapons
of the Last Hunter-gatherers of the Northern Alps

Lorène CHESNAUX

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Abstract

In this paper, I present interpretations of the stigmata of fabrication (observation of retouch methods) and use (observation of impact traces and hafting glue residues) of microliths and hyper-microliths (arrowheads) of the Middle Mesolithic Sauveterrian period. Based on the first results obtained from the sites of Grande Rivoire, Pas de la Charmate (Vercors, Isère) and Sinard (Trièves, Isère), a reconstruction of the hafting modes of these tools is proposed. The results of a first experimental test are also presented.

To cite this article

Chesnaux L., 2009 – Sauveterrian Microliths: Evidence of the Hunting Weapons of the last Hunter-gatherers of the Northern Alps, in Pétillon J.-M., Dias-Meirinho M.-H., Cattelain P., Honegger M., Normand C., Valdeyron N., Projectile Weapon Elements from the Upper Palaeolithic to the Neolithic, Proceedings of session C83, XVth UISPP World Congress, Lisbon, September 4-9, 2006, P@lethnology, 1, 133-146.