francois LEVEQUE

The question of function of hearths in prehistorical caves is fundamental to characterize the nature of human occupation. The hearths could be used for lightning, cooking or heating. Their spatial repartition, as their paleotemperature, should allow to identify their function. The ...

ABSTRACT Magnetic survey realized with the simultaneous determination of the coordinates of the magnetic field measurement, with centimeter accuracy, at rates of 10 to 20 measurements per second, opens new horizon. It allow to realize a change of scale from the site to the objet. Few square meters can be covered at a sub-decimetric resolution. At this scale, a 3D information is required to discern changes in the local magnetic field produced by the relief of those resulting magnetization variations within the studied object. Complex environment such as cavities can be thus explored. Outdoors, the complexity of large heating structures or relics such as wrecks can also be revealed.

ABSTRACT In the cave of Les Fraux (Dordogne, France), the numerous traces of fires raise the questions of function of the site and of the way of life of the Bronze Age human groups inside the cave. The study of hearths is one possible way to answer those questions. This paper presents the methodology developed for the first time in the cave of les Fraux for the study of hearths. It consists in three parts: (1) the thermal characterization of sediment of the hearth; (2) the experimentation of fires; (3) the simulation of propagation of heat in the sediment. The thermal characterization is based on the examination of the thermoluminescence (TL) of quartz grains (from localized samples) and a map of magnetic susceptibility which is mainly brought by iron oxides contained in sediments. First, a map of magnetic susceptibility was built on the surface of the studied hearth and allowed the location of the heated zones. Then samples were extracted from the sediment along gradient of magnetic susceptibility located on the map. After the extraction of quartz grains, measurements of TL gave the paleotemperature attained by the sediment samples. This determination is based on the comparison between ’natural’ TL curves of samples and ’simulated natural’ TL curves of thermal references. The latter were made by heating, in laboratory, sediment from the cave with the same geological origin than hearth samples. They were heated according to an arbitrary and reproducible thermal cycle: heating at 20°C/min, one hour at the maximal temperature and subsequently cooling at 5°C/min. Thirteen thermal references were created with their maximal temperature ranged between 200°C and 650°C, keeping an unheated sample. The comparison allowed to associate one temperature to each sample. Then, the trend between paleotemperature and magnetic susceptibility permits to express magnetic susceptibility as a function of the paleotemperature and to obtain a map of temperature of the studied hearth. These results give some data about intensity of fires. To compare the fire effect observed on archaeological heated sediment and paleotemperature found, experimentations of fires were made. A substratum of sandstones and clay extracted from non-archaeological zones of the cave of Les Fraux was built. Temperatures in different positions and depths were recorded during firing and matched quite well with the surface paleotemperatures of archaeological hearth. Even the changing of sediment color seems to be identical. Finally, some tests of simulation of heat propagation were made in a homogeneous substratum. After a validation of the numerical modeling with the experimental data, it is possible to observe at different times the propagation of the heat. The methodology based on in situ and laboratory measurements, experimentations and simulations need to be supplement. The thermal characterization of a second hearth is begun, completed by a complete study of magnetic properties of the sediment in order to see if it is possible to obtain a new paleothermometer from magnetic mineralogy. A second step of experimentations of fires in underground environment and simulations in heterogeneous substratum are planned. Finally, it is hope that these reciprocal approaches will give clues to understand the function of the hearths and thus data on occupation of the site.

During the 10th Castel Meeting we have showed magnetic maps realized on agronomical soils with spatial resolution of 40 measures by m² (Mathé and Lévêque, 2003; Mathé et al., 2006; Lévêque and Mathé, 2006). The soils studied present pseudoperiodic magnetic ...

The archaeological cave « Les Fraux » (Saint-Martin-de-Fressengeas, Dordogne) forms a great network of galleries dated from the Bronze Age where several domestic fireplaces, ceramic and metal deposits, as well as fingerprints incised in the clayey-walls have been discovered. The study of this site is supported by the Institute of Ecology and Environment of the French Council of Scientific Research. Several data recording methods have been tested in this so-called observatory of global ecology, according to an interdisciplinary way. A partnership among archaeologists, geophysicists and surveyors has been working since 2008 on the 3D recording of the global volume of the cave, the high resolution digitizing of the parietal engravings and fingerings, ceramics and finds, as well as on the development of a protocol suitable for the underground magnetic survey. The aim of this paper is to present the 3D recording methods and their instruments and the resulting detailed documentation avail...

For six years, an interdisciplinary team carried out the study of a Bronze Age underground network. This program has been labelled by the Institute of Ecology and Environment of the French Research Council (CNRS), who wants to promote new methodologies and experimental studies in Global Ecology. It takes advantage of the support of the French Ministry of Culture. The archaeological cave of Les Fraux (Saint-Martin-de-Fressengeas, Dordogne) is the only protohistorical site in Europe wherein are gathered testimonies of domestic, spiritual and artistic activities. Fortunately, the cave was closed at the end of the Bronze Age, following to the collapse of its entrance. The site is currently registered in the French Historical Monuments. The cave forms a wide network of galleries, characterized by the exceptional richness of its archaeological remains such as ceramic and metal deposits, numerous parietal representations (engravings or fingerings incised in the clay-walls and paintings sometimes in association with deposits) and about sixty domestic fireplaces. In that framework, 3D models of the cave constitute the common work support and the best way for scientific communication for the various studies conducted on the site by nearly forty researchers. In this specific context, a partnership among archaeologists and surveyors from INSA Strasbourg allows the team to develop, in an interdisciplinary way, new methods of data acquiring based on contact-free measurements techniques in order to acquire a full 3D-documentation. All the surveys are conducted in compliance with the integrity of the site. Different techniques based on Terrestrial Laser Scanning, Digital Photogrammetry and Spatial Imaging System have been used in order to generate a geometric and photorealistic 3D model from the combination of point clouds and photogrammetric images, for both visualization and accurate documentation purposes. Various scales of acquiring and diverse resolutions have been applied according to the subject: global volume cave, parietal representations, deposits… The aim of this paper is firstly to issue a statement of 6 years of 3D-recording in the cave and secondly to display recent methodological developments as for the integration of heterogeneous data in 3D models (i.e. magnetic field recording combined with the 3D models in order to locate magnetic anomalies in the cave). Another purpose is to give an overview of methodological and technological limitations we experienced since 2008. Finally, we attempt to present work in progress as to 3D-modelling and simulating and thinking on the way we should use 3D in archaeological caves.

Les nombreuses traces de feux visibles au sein de la grotte des Fraux (Dordogne, France) posent des questions sur la
fonction du site et sur les conditions de vie des hommes de l’Âge du Bronze à l’intérieur de la grotte. L’étude des foyers
est une des voies pour répondre à ces questions. Cet article présente la méthodologie mise en place pour la
caractérisation thermique des foyers. Elle est fondée sur l’observation de la thermoluminescence (TL) de grains de
quartz (provenant d’échantillons ponctuels) et sur une carte de susceptibilité magnétique, laquelle est principalement
portée par les oxydes de fer contenus dans les sédiments. La carte de susceptibilité magnétique permet de repérer et
délimiter les zones chauffées. La TL permet d’obtenir une température équivalente maximum (paléotempérature)
atteinte par le sédiment, en comparant les courbes TL des échantillons avec celles de références thermiques (réalisées à
partir de sédiment de la grotte chauffé en laboratoire selon un cycle thermique arbitraire et reproductible). La
tendance observée entre la paléotempérature et la susceptibilité magnétique permet d’exprimer la susceptibilité
magnétique comme une fonction de la température. Ces informations nous renseignent sur l’intensité des feux. Des
expérimentations de feux et simulations de la propagation de la chaleur ont été réalisées pour observer et comparer
l’effet thermique des feux sur le substrat. Cette approche croisée apportera dans le futur des indices pour comprendre
la fonction des foyers et à travers elle, la fonction du site.

... 1 Centre Littoral de Géophysique, avenue M. Crépeau, 17042 La Rochelle cedex 01, France, and 2 Laboratoire HydrASA, CNRS-UMR ... XRD patterns were decomposed into elementary curves, Gaussian or Lorentzian functions, using the DECOMPXR software of Lanson (1997 ...

The marshlands of western France provide the opportunity to relate the magnetic properties of a recent sedimentary clay soil to pedogenesis, including the impact of agriculture and drainage on magnetic mineralogy. We studied a plot of drained land that had been ploughed up to 1998 and under grass since. A new thermomagnetic method was used to identify and to quantify roughly the magnetic minerals, which represent less than 1 g kg−1. The most abundant Fe oxides are haematite (45%) and goethite (45%). However, trace amounts of the ferrimagnetic minerals maghemite (4%), magnetite (3%) and, to a lesser extent, iron sulphides (1%) provide most of the magnetic signal. This signal allowed us to identify magnetic horizons that relate to the soil horizons. The topsoil is characterized by a strong magnetic enhancement (4-fold), and the thickness of this layer increases close to the drains. Relative contents of ferrimagnetic phase also increase laterally with decreasing distance to the drains. Magnetic enhancement coincides with the most aerated and developed layer, in which water circulation, root colonization and hence soil fertility are greater. Ferromagnetic minerals sensu lato, especially maghemite and magnetite, can be considered as mineralogical tracers partly and indirectly reflecting soil fertility of these clay-rich marshland soils.

This paper presents the results of high resolution magnetic cartography realized with a caesium vapor magnetometer on marshland plots in Western France. This site is interesting because of the clayey substratum homogeneity and the historical knowledge of plot exploitation. A wooden truck running on PVC rails allowed acquisition of accurate signals with dynamics of about 2 nT. Natural grassland presents weak decametric variations correlated to a micro-toposequence. Conversely, plots recently tilled show linear magnetic anomalies. These anomalies are interpreted as the effect of tractor tyre soil compaction which modify soil properties. In addition, the study of a drained plot, by a wavelet transform, reveals the presence of a frequency band close to the drain intervals. Moreover, the magnitude of the linear magnetic anomalies is higher above drains. This suggests that the compaction influence on the magnetic carriers is more important in drained, hence aerated, zones.

Caesium magnetometers are new tools for soil property mapping with a decimetric resolution [Mathé, V., Lévêque, F., 2003. High resolution magnetic survey for soil monitoring: detection of drainage and soil tillage effects. Earth and Planetary Science Letters 212 (1–2), 241–251]. However, when the magnetic anomalies are only a few nanoteslas (nT), the geologic and pedogenic signal must first be isolated from magnetic disturbances for this method to be useful. This paper investigates the instrumental artifacts and environmental disturbances to adapt the survey protocol to slightly magnetic soils.Among the possible instrumental sources of disturbances listed and quantified, the most significant are: 1) The battery effect upon sensors 2 m away (classic protocol, about ± 0.15 nT) while increasing this distance up to 10 m cancelled it; 2) The noise level of magnetometers and sensors, which, according to tests on two magnetometers and three sensors, rarely and randomly exceeds 0.1 nT, but seems to increase with the electronic component age.Among the environmental disturbances, temporal variations such as diurnal variation or fluctuations linked to the moving of metallic masses play a major role, although the pseudogradient or base-station methods have commonly cancelled them. The efficiency of the latter is strongly dependent on the source nature. However, the ground currents and electromagnetic fields propagating in soils cause more problems. As a first step to better understand such disturbance sources, uncommon magnetic signal variations supposedly due to electromagnetic wave conversions and likely linked to the railway traffic are presented.Based on previous results, an adapted protocol using one magnetometer and two caesium sensors (0.3 and 1.6 m above the surface) is proposed to increase the signal / noise ratio. At first, to maintain an accurate horizontal and vertical location of the sensors, the latter are affixed to a wooden handcart running on plastic rails. Rails adapt to micro-topography, thereby decreasing strongly the soil–sensors distance variations. Anomalies due to topography rarely exceed 0.1 nT. Finally, a method to remove diurnal variations from high-resolution magnetic maps is proposed. Parallel profiles performed successively are adjusted by a cross-profile. Assuming that the temporal variations during each profile are negligible (less than 0.05 nT), this technique, contrary to the pseudogradient, preserves both the decimetric and the metric anomalies (gain of more than 1 nT).

Caesium magnetometers are new tools for soil property mapping with a decimetric resolution [Mathé, V., Lévêque, F., 2003. High resolution magnetic survey for soil monitoring: detection of drainage and soil tillage effects. Earth and Planetary Science Letters 212 (1–2), 241–251]. However, when the magnetic anomalies are only a few nanoteslas (nT), the geologic and pedogenic signal must first be isolated from magnetic disturbances for this method to be useful. This paper investigates the instrumental artifacts and environmental disturbances to adapt the survey protocol to slightly magnetic soils.Among the possible instrumental sources of disturbances listed and quantified, the most significant are: 1) The battery effect upon sensors 2 m away (classic protocol, about ± 0.15 nT) while increasing this distance up to 10 m cancelled it; 2) The noise level of magnetometers and sensors, which, according to tests on two magnetometers and three sensors, rarely and randomly exceeds 0.1 nT, but seems to increase with the electronic component age.Among the environmental disturbances, temporal variations such as diurnal variation or fluctuations linked to the moving of metallic masses play a major role, although the pseudogradient or base-station methods have commonly cancelled them. The efficiency of the latter is strongly dependent on the source nature. However, the ground currents and electromagnetic fields propagating in soils cause more problems. As a first step to better understand such disturbance sources, uncommon magnetic signal variations supposedly due to electromagnetic wave conversions and likely linked to the railway traffic are presented.Based on previous results, an adapted protocol using one magnetometer and two caesium sensors (0.3 and 1.6 m above the surface) is proposed to increase the signal / noise ratio. At first, to maintain an accurate horizontal and vertical location of the sensors, the latter are affixed to a wooden handcart running on plastic rails. Rails adapt to micro-topography, thereby decreasing strongly the soil–sensors distance variations. Anomalies due to topography rarely exceed 0.1 nT. Finally, a method to remove diurnal variations from high-resolution magnetic maps is proposed. Parallel profiles performed successively are adjusted by a cross-profile. Assuming that the temporal variations during each profile are negligible (less than 0.05 nT), this technique, contrary to the pseudogradient, preserves both the decimetric and the metric anomalies (gain of more than 1 nT).

This paper presents the results of high resolution magnetic cartography realized with a caesium vapor magnetometer on marshland plots in Western France. This site is interesting because of the clayey substratum homogeneity and the historical knowledge of plot exploitation. A wooden truck running on PVC rails allowed acquisition of accurate signals with dynamics of about 2 nT. Natural grassland presents weak decametric variations correlated to a micro-toposequence. Conversely, plots recently tilled show linear magnetic anomalies. These anomalies are interpreted as the effect of tractor tyre soil compaction which modify soil properties. In addition, the study of a drained plot, by a wavelet transform, reveals the presence of a frequency band close to the drain intervals. Moreover, the magnitude of the linear magnetic anomalies is higher above drains. This suggests that the compaction influence on the magnetic carriers is more important in drained, hence aerated, zones.

... 1 Centre Littoral de Géophysique, avenue M. Crépeau, 17042 La Rochelle cedex 01, France, and 2 Laboratoire HydrASA, CNRS-UMR ... XRD patterns were decomposed into elementary curves, Gaussian or Lorentzian functions, using the DECOMPXR software of Lanson (1997 ...

A novel approach to the intensity of archaeological fires is proposed, based on a combination of archaeological
observations and analyses of sedimentary hearths with relevant proxies obtained from using experimental combustion structures. In this work, two different structures were built and monitored. They aimed at reproducing two types of archaeological hearth morphology encountered at the Bronze Age site of the cave of Les Fraux (Saint Martin de
Fressengeas, Dordogne, France). A series of fires was constructed and a large amount of data was collected: temperature curves, wood consumption and observations on substratum evolution. A numerical code for heat transfer was developed to model heat propagation from the surface to the underlying sedimentary layers, the input parameters of which were adapted to fit the thermal evolution observed with the
experimental fires. We found that two archaeological
parameters are fundamental to characterise the intensity of
the fire: the paleotemperature reached at the surface of the
burnt sediment (which in our case was determined by thermoluminescence analyses) and the depth of the rubefaction front as an indicator of a 250 °C isothermal surface. We then estimated the duration of an equivalent single fire that would correspond to one of the archaeological hearths investigated. Finally, with the wood consumption recorded during the fire experiments, and the estimated firing duration, the energy involved was evaluated. When generalised to the study of archaeological hearths, this approach could be of great interest in firing intensity evaluation (temperature/time/energy).

Numerous sorts of evidence of fires were observed in the cave of Les Fraux (Dordogne, France) and in particular the effects of fire on sediment were studied for a better understanding of their use centuries ago. Our present objective is the evaluation of the firing intensity by determining the past temperature (paleotemperature) attained by the topmost sediment of the archaeological fires. The principle of paleotemperature determination is based on the thermoluminescence (TL) properties of quartz and the magnetic susceptibility of the sediment. By comparing the TL signal of anciently heated quartz to the TL signal of thermal references made in the laboratory, we were able to obtain a maximal equivalent temperature attained for each sample extracted from ancient fires. The magnetic susceptibility (previously measured on the hearth surface) could thus be estimated as a function of temperature. The main result of this study is the temperature mapping of the hearth which can be used as meaningful information about the ancient firing intensity.

ABSTRACT This paper describes an interdisciplinary study of the Neolithic causewayed enclosure of Bellevue (Chenommet, France). Geophysical investigations and archaeological excavations were used alternately in order to optimize the acquisition of accurate data at different spatial scales: mapping of major structures was obtained by magnetic prospection of the whole site, while excavation identified small features weakly expressed in the prospecting results. Measurements of magnetic susceptibility and total magnetic field anomalies were also recorded during the excavation in order to identify the source of the magnetic signal of the ditches. This mutual transdisciplinary contribution is also methodological: the geophysics reveals archaeological information invisible to the eye of the archaeologist and, in turn, the excavation allows refinement of the interpretation of the geophysical data by identifying the sources of signal variations. This article presents the results of the first comprehensive magnetic mapping of a Neolithic causewayed enclosure in the west of France. Copyright © 2014 John Wiley & Sons, Ltd.

In the cave of Les Fraux (Dordogne,
France) numerous traces of fires are visible
in the galleries. A multidisciplinary investigation
was carried out to study these fires.
This paper presents the methodology applied
for the hearth study. It is based on the examination
of the thermoluminescence (TL) of
quartz and the magnetic susceptibility of iron
oxides. First of all, magnetic susceptibility
was measured on the surface of hearths.
Based on both susceptibility mapping and
visible sediment characteristics, small sediment
samples (1-2 g) were taken.
Subsequently, quartz grains were extracted
from the sediment samples. Fourteen thermal
references were obtained by heating
(from 200 to 650°C) fractions of the pristine
unfired cave sediment. Comparing the TL
signal of anciently heated quartz to the reference
samples allowed to obtain the maximum
equivalent temperature attained for each
sample extracted from ancient fires.
Consequently, the correspondence between
magnetic susceptibility and temperature
allowed for the reconstruction of a paleotemperature
map of the study area. This research
provides information about fire intensity in
the cave, which can help to understand its
function.

An interdisciplinary team of archaeologists, surveyors, environmentalists and archaeometrists has jointly carried out the study of the Bronze Age "Les Fraux" (Saint-Martin-de-Fressengeas, Dordogne, France) since 2007. This archaeological decorated cave, registered as a French Historical Monument, forms a wide network of galleries, characterized by the exceptional richness of its archaeological remains such as ceramic and metal deposits, parietal representation and domestic fireplaces. This cave is the only protohistorical site in Europe wherein testimonies of domestic, spiritual and artistic activities are gathered. This project has been labelled by the Institute of Ecology and Environment of the French Research Council (CNRS), who wants to promote new methodologies and experimental studies in Global Ecology. Accurate 3D models of the cave constitute the common framework for the different partners. We present in this paper an overview of methods of data recording based on contact-free measurement techniques in order to acquire a full 3D-documentation of the site. Different techniques based on Terrestrial Laser Scanning, Digital Photogrammetry and Spatial Imaging have been used in order to generate geometric and photorealistic 3D models from the combination of point clouds and photogrammetric images, for both visualization and accurate documentation purposes. Various scales of acquiring and diverse resolutions have been applied according to the subject, e.g. global volume of the cave, parietal representations, and deposits. Measurements from an original method of 3D indoor magnetic field recording are combined with the 3D models in order to locate magnetic anomalies in the cave. All the surveys are conducted in compliance with the integrity of the site.

"AFTER THE FLOOD: GEOMORPHOLOGICAL EVOLUTION OF THE DANUBE DELTA AFTER THE BLACK SEA - MEDITERRANEA
RECONNECTION AND ITS IMPLICATIONS ON ENEOLITHIC / CHALCOLITHIQUE SETTLEMENTS
In this work, we document the evolution of the upper Danube delta (i.e. blocked delta) using archaeological, geomorphological
and geoarchaeological approaches, after the discovery, in the 90’s, of the oldest human settlement (Eneolithic/Chalcolithic) close to Mila 23 district. In-site and out-site fieldwork allows us to refine the Danube delta early evolution from 5,600 to 4,000 cal. yr BC.
During this period, it functions like a fresh bayhead delta, flowing into a huge lagoon isolated from the open sea by the Letea-Caraorman spit. Then, lagoon water level rose rapidly due to an eustatic rise, and possibly from an unusual highstand of sealevel resulting from wet conditions. The settlement was then partially flooded and abandoned around 4,450 cal. yr BC."

Dans ce travail, l’évolution de la zone interne du delta du Danube est appréhendée à partir de travaux géoarchéologiques et
géomorphologiques réalisés dans le district de Mila 23, suite à la découverte de la plus vieille occupation humaine (énéolithique/
chalcolithique) du delta dans les années 90. Les travaux sur site et hors site ont permis de préciser les stades précoces de l’évolution
du delta entre 5 600 et 4 000 ans cal. av. J.-C. Celui-ci évolue comme un delta lagunaire en eau douce, s’épandant dans un large lagon séparé de la mer par la ride de Letea-Caraorman. La remontée rapide du niveau lagunaire, sous l’effet de la remontée eustatique et peut-être d’une sur cote liée à un événement humide, ont conduit à une submersion partielle du site et probablement à son abandon vers 4 450 ans cal. av. J.-C.

"The question of function of hearths in prehistorical caves is fundamental to characterize the nature of human occupation. The hearths could be used for lightning, cooking or heating. Their spatial repartition, as their paleotemperature, should allow to identify their function. The localization can be visual by the presence of ash and charcoal or by identication of rubefaction. The accumulation of ash and charcoal can also correspond to the emptying of hearths and the rubefaction can be chemical than thermal. The accumulation of ash and charcoal can correspond to the emptying of hearths and the rubefaction can be chemical instead of thermal.
The thermoremanent magnetization and the neoformation of magnetic minerals, together induced by heating, produce an importante deformation of the local magnetic field. Thus, the local variations of the magnetic field may allow to localize and to count the hearths without mistake even if the hearths are masked by a draping of clayed deposit.
The walls caves morphology are also sources of local deformations of the magnetic field. For this reason it is important to have a 3D information on the deformation of the magnetic field. Moreover, the geolocalisation is difficult in the caves. To resolve these different problems for such kind of prospect, the 3D mapping was realized by tracking the sensor position with a laser tacheometer during the deplacement of the sensor in the space.
The protocol was developed in the cave of “les Fraux” (Saint-Martin-de-Fressengeas, Dordogne, France), accidentally discovered in 1989 (Carozza et al., 2009). This cave is a rare example of a Bronze Age site (1300 BC) with archaeological vestiges (ceramics, bones, hearths) and rock art (incision, engraving, finger plot). The conservation of this site is exceptional as the cave entrance just collapsed after the last occupation by man, 3300 years ago.
The experimental contraint in this recent prehistorical cave are low compare to the older ones. This allows us to developpe a new approach to estimate the paléotemperatures of hearths (Brodard et al., 2012).
"

The cave of Les Fraux (Dordogne, France) is an exceptionally preserved Bronze Age site with both archaeological vestiges and rock art. Numerous traces of fires were observed and we were particularly interested in studying their effects on sediment to better understand their use centuries ago. Our present objective is the evaluation of the intensity of the fires by determining past temperature (palaeotemperature) attained by the sediment. The principle of palaeotemperature determination is based on thermoluminescence (TL) properties of quartz and magnetic susceptibility of the sediment. First, a cartography of magnetic susceptibility was made in situ. On the basis of both susceptibility cartography and visual patterns of sediment, small samples (1 - 2 grams) were taken out. Quartz grains were extracted from these sediment samples. Besides, fourteen thermal references were processed by heating fractions of the pristine sediment of the cave (unfired) that was also sampled. They were heated in air in an electric oven according to an accurately designed thermal protocol. Each fraction was heated at a maximum temperature varying from 200°C to 650°C, keeping an unheated sample as a witness. The TL signal shows significant variation allowing the palaeotemperature determination. By comparison of TL signal of anciently heated quartz to the reference ones, we were able to obtain the maximum equivalent temperature attained for each samples extracted from ancient fires. Thanks to that we could estimate magnetic susceptibility as a function of temperature and draw palaeotemperature cartography of the studied areas. The next step will be archaeological experimentations of fires that will allow us to validate our methodology and model fires by their intensity, issued energy (light and heat), quantity of wood consumed in a given duration. That project will contribute to a better identification of the function of the site.