ETEC

The environmental impact of the Norse landnám (colonization) in Greenland has been studied extensively. But to date, no study has quantified the soil erosion that Norse agricultural practices are believed to have caused. To resolve this problem, a high resolution sedimentary record from Lake Igaliku in South Greenland is used to quantitatively reconstruct 2500 years of soil erosion driven by climate and historical land use. An accurate chronology, established on 18 AMS 14C, and 210Pb and 137Cs dates, allows for the estimation of detritic fluxes and their uncertainties. Land clearance and the introduction of grazing livestock by the Norse around 1010 AD caused an acceleration of soil erosion up to ∼8 mm century−1 in 1180 AD which is two-fold higher than the natural pre-landnám background. From 1335 AD to the end of the Norse Eastern Settlement (in the mid-fifteenth century), the vegetation began to recover from initial disturbance and soil erosion decreased. After an initial phase of modern sheep breeding similar to the medieval one, the mechanization of agriculture in the 1980s caused an unprecedented soil erosion rate of up to ∼21 mm century−1, five times the pre-anthropogenic levels. Independently, a suite of biological and geochemical proxies (including Ti and diatom concentrations, C:N ratio, δ13C and δ15N of organic matter) confirm that the medieval and modern anthropogenic erosion far exceeds any natural erosion over the last 2500 years. Our findings question the veracity of the catastrophic scenario of overgrazing and land degradation considered to have been the major factor responsible for Norse settlement demise. They also shed light on the sustainability of modern practices and their consequences for the future of agriculture in Greenland.► First quantification of soil erosion from a lake deposit of South Greenland. ► Medieval agriculture caused a two-fold increase in soil erosion. ► Early soil erosion decrease contradicts the theory of land degradation by the Norse. ► Modern hay-making caused an unprecedented acceleration of soil erosion (x5).

Interdisciplinary research was carried out in mid-level mountain areas in France with the aim of documenting historical mining and smelting activities by means of pollen and geochemical analyses. These investigations were made on cores collected in French peatlands in the Morvan (northern Massif Central), at Mont Lozère (southern Massif Central) and in the Basque Country (Pyrénées). Different periods of mining were recognised from Prehistory to modern times through the presence of anthropogenic lead in peat. Some of these were already known from archaeological dates or historical archives, especially for mediaeval and modern periods. However prehistoric ancient mining activities, as early as the Middle Bronze Age (ca. 1700 b.c.), were also discovered. They had all led to modifications in plant cover, probably related in part to forest clearance necessary to supply energy for mining and smelting.

Interdisciplinary research was carried out in mid-level mountain areas in France with the aim of documenting historical mining and smelting activities by means of pollen and geochemical analyses. These investigations were made on cores collected in French peatlands in the Morvan (northern Massif Central), at Mont Lozère (southern Massif Central) and in the Basque Country (Pyrénées). Different periods of mining were recognised from Prehistory to modern times through the presence of anthropogenic lead in peat. Some of these were already known from archaeological dates or historical archives, especially for mediaeval and modern periods. However prehistoric ancient mining activities, as early as the Middle Bronze Age (ca. 1700 b.c.), were also discovered. They had all led to modifications in plant cover, probably related in part to forest clearance necessary to supply energy for mining and smelting.

Klasifikace seker s lištami datovanými do střední doby bronzové je velice složitá. V literatuře se lze setkat s obrovským množstvím různých typů seker, mnohé z nich se navíc skládají z řady variant. Například v současně uznávané francouzské terminologii jsou sekery s lištami prezentovány dvěma velkými skupinami: „atlantickými“ a „orientálními“ formami. Obě skupiny jsou nicméně velice polymorfní a často lze podle nich obtížně typologicky klasifikovat. Dokládá to například i fakt, že sekery typu Armorican tumuli (atlantická skupina) a Neyruz (orientální skupina), obě sestávající z celé řady variant, jsou si na první pohled vizuálně velice podobné. Tyto skutečnosti nicméně nebrání archeologům v interpretaci některých důležitých otázek; týkajících se například vlivu orientálního typu na atlantický a vice-versa. V prvé řadě jsme proto pomocí analýzy uzavřených kontur (Eliptická Fourierova Analýza) aplikované na siluety 268 seker testovali vhodnost stávajícího klasifikačního modelu. Jelikož tento model dobře nevysvětloval strukturování seker založené na tvarové podobnosti, navrhli jsme novou tvarovou klasifikaci za použití neřízených modelů shlukové analýzy a diskriminačních metod založených na Gaussovských modelech. Tato klasifikace byla následně validována pomocí prostorové distribuce nálezů za použití multinomiální skenovací statistiky. Poslední krok sestával z přiřazení jedinců s neznámým členstvím (sekery-ingoty) do jedné z nově vytvořených skupin.

The classification of flanged axes dated to the middle Bronze Age is very complex. Many types of axes exist, and most of them are composed by numerous variants. For example, in the recent and well-established French terminology, those axes are represented by two generic groups: namely “atlantic” and “oriental” forms. Both groups are nevertheless very polymorph so that it is often very difficult to classify the individuals. It can be illustrated for example by the fact that axes of armorican tumulus type (Atlantic group) and Neyruz type (Occidental group), both consisting of number of variants, are at the first sight visually very similar. Nevertheless, those facts do not prevent archaeologists from interpreting some important questions, for example those concerning the influences of oriental type on atlantic and vice-versa. At the first stage, we aimed at checking the pertinence of the current typology at the light of a morphometric analysis based on the treatment by a closed contour approach (Elliptic Fourier Analysis) of 268 axes. As the current typological model does not explain well the structuring of axes based on the shape similarity, we proposed a new formal classification, using an unsupervised clustering and discriminant methods based on the Gaussian mixture modelling. Once this step performed, we validated this classification via a spatial distribution of findings using a multinomial scan statistics. The final step consisted in introducing new individuals (axes-ingots) of unknown membership to attribute them to the one of the newly established groups.

Tato prezentace představuje kvantitativní určení konkordance mezi morfometrickými metodami a tradiční typologií. Jako case study byl zvolen soubor 154 kompletně dochovaných keramických nádob z oppida Bibracte ve Francii. Byly zvoleny dvě metody založené na analýze kontur: eliptická Fourierova analýza a diskrétní kosinová transformace. Byly kombinovány několika standardizačními a normalizačními technikami. Tento přístup může být jednoduše generalizován a jednoduše aplikován na jakýkoliv druh archeologických artefaktů za účelem studia standardizace produkce a vývoje tvaru artefaktů v čase a prostoru stejně jako ke studiu materiálních a kulturních vztahů.

This presentation presents the quantitative evaluation of the concordance between morphometrical methods and traditional typology, with a corpus of 154 complete ceramic vessels from the Bibracte oppidum, France, used as a case study. Two outline-based approaches were selected: the Elliptic Fourier Analysis and the Discrete Cosine Transform. They were combined with numerous methods of standardisation/normalisation. The approach described here can easily be generalised and adopted for other kinds of artefacts, to study the level of production standardisation and the evolution of shape over space and time, and to provide information about material and cultural exchanges.

Although the potential of geometric morphometrics for the study of archaeological artefacts is recognised, quantitative evaluations of the concordance between such methods and traditional typology are rare. The present work seeks to fill this gap, using as a case study a corpus of 154 complete ceramic vessels from the Bibracte oppidum (France), the capital of the Celtic tribe Aedui from the Second Iron Age. Two outline-based approaches were selected: the Elliptic Fourier Analysis and the Discrete Cosine Transform. They were combined with numerous methods of standardisation/normalisation. Although standardisations may use either perimeter or surface, the resulting morphospaces remain comparable, and, interestingly, are also comparable with the morphospace built from traditional typology. Geometric morphometrics also present the advantage of being easily implemented and automated for large sets of artefacts. The method is reproducible and provides quantitative estimates, such as mean shape, and shape diversity of ceramic assemblages, allowing objective inferences to be statistically tested. The approach can easily be generalised and adopted for other kinds of artefacts, to study the level of production standardisation and the evolution of shape over space and time, and to provide information about material and cultural exchanges.

We provide a new paleoenvironmental record of lead concentrations and lead isotopic compositions from southern Greenland.The geological background is not favorable to the direct determination of anthropogenic fluxes.We used inverse modeling to estimate anthropogenic lead deposition through time.The model is validated by the coherence of the results obtained from two independent records.The aim of this study is to model atmospheric lead fluxes in two different paleoenvironmental records located in southern Greenland. Fifty five sediment samples collected from the Lake Igaliku sedimentary sequence were analyzed for lead and aluminum concentrations, and lead isotopic compositions. The second archive consists in a previously published dataset, obtained from a minerogenic peat deposit, located at Tasiusaq, 16 km northwest from Lake Igaliku. A flux model fitted to both dataset produces similar results, allowing past anthropogenic atmospheric deposition to be reconstructed. This original method can be easily adapted for other studies where natural inputs dominate over discrete anthropogenic inputs.

The classification of Western European flanged axes dating to the Middle Bronze Age (1650–1350 BC) is very complex. Many types of axe have been identified, some of which have numerous variant forms. In the current French terminology, all axes are divided into two generic groups: namely “Atlantic” (Atlantique) and “Eastern” (Orientale). Each of these generic groups, however, is highly polymorphic, so that it is often very difficult for the operator to classify individual axes with absolute confidence and certainty. In order to overcome such problems, a new shape classification is proposed, using morphometric analysis (Elliptic Fourier Analysis) followed by unsupervised model-based clustering and discriminant analysis, both based on Gaussian mixture modelling. Together, these methods produce a clearer pattern, which is independently validated by the spatial distribution of the findings, and multinomial scan statistics. This approach is fast, reproducible, and operator-independent, allowing artefacts of unknown membership to be classified rapidly. The method is designed to be amendable by the introduction of new artefacts, in the light of future discoveries. This method can be adapted to suit many other archaeological artefacts, providing information about the material, social and cultural relations of ancient populations.

For archaeologists, metallic artifacts are key materials to assess Middle Bronze Age production areas and cultural exchanges. Here, a set of 629 bronze palstaves excavated in northern France, belonging to Breton and Norman typological groups, was treated by (open) outline-based morphometrics with orthogonal polynomial regression. Using robust statistics developed for outlier detection, these Norman and Breton
palstave outlines can be divided into two groups: those for which the shape fluctuates close to the standard shape, called “congruent” axes, and those which are far enough from this standard to be considered as “non-congruent”, although they possess most of the features of the typological group. The
highest density of discovery (whether congruent and non-congruent in shape) is in the extreme east of Brittany for the Breton axes, while the Norman axes are concentrated in northern Normandy, hence the choice of names. However, the distribution of congruent and non-congruent artifacts appears to be spatially dependent for the Norman group, and to a lesser extent for the Breton group, as there are
proportionally more congruent specimens inside the  supposed production areas than outside. This contradicts the generally accepted archaeological scheme which hypothesizes that all axes in a group originate from the same production center, and that some items were exported from there to supply neighboring regions. Other minor production centers probably existed, copying the original model with greater shape variation.

The present study proposes a technological transfer from modern mining prospection to the field of
archaeology, providing a methodology to facilitate the discovery of ancient mining sites. This method
takes advantage of the thousands of geochemical analyses of streambed sediments, performed by national
geological surveys to inventory mineral substances. In order to delineate geochemical anomalies,
the datasets are treated following two different approaches: Exploratory Data Analysis and a fractalbased
method often recognised as more powerful. Mineral prospectivity maps are then obtained by
combining the results with a geographical information system. The surroundings of the Celtic oppidum
of Bibracte, French Massif Central, known to have been mined at least since the Late Bronze Age until
Modern Times, have been chosen to exemplify the method’s potential in archaeology. First, an exhaustive
record of the mining sites was undertaken over a pilot area by pedestrian prospection. If mineral prospectivity
maps had been used as guidelines, w70% of these mines would have been discovered by
prospecting only w15e20% of the whole area whatever the method used to treat the dataset. At least for
our specific case, the multifractal approach is as powerful as EDA. Besides saving a significant amount of
time and effort, the methods described here may supply clues for determining the nature of mineral
substances exploited in the past, when such information cannot be straightforwardly obtained from the
field or from textual archives. It should however be noticed that this approach is proposed as a first step
before peer archaeological investigation following more conventional methods. Technically, there is no
real obstacle to the application of the methodology proposed here, because (i) software and associated
packages are freely available from the web, as well as original geochemical datasets (at least in France),
and (ii) minimal mathematical skills are required.

This study evaluates the potentialities of a lab-made pLIBS (portable Laser-Induced Breakdown Spectroscopy) to
sort volcanic rocks belonging to various magmatic series. An in-situ chemical analysis of 19 atomic lines, including
Al, Ba, Ca, Cr, Cu, Fe, Mg,Mn, Na, Si, Sr and Ti, from21 sampled rockswas performed during a field exploration
in Iceland. Iceland was chosen both for the various typologies of volcanic rocks and the rugged conditions in the
field in order to test the sturdiness of the pLIPS. Elemental compositions were also measured using laboratory
ICP-AES measurements on the same samples. Based on these latter results, which can be used to identify three
different groups of volcanic rocks, a classification model was built in order to sort pLIBS data and to categorize
unknown samples. Using a reliable statistical scheme applied to LIBS compositional data, the classification capability
of the pLIBS system is clearly demonstrated (90–100% success rate). Although this prototype does not provide
quantitative measurements, its use should be of particular interest for future geological field investigations.