Archaeomagnetism of four pottery kilns in central Portugal: Implications for secular variation and dating

We report archaeomagnetic results from four pottery kilns in Portugal which are thought to belong to the period of Roman rule (3rd Century BCE-4th Century CE). Very few details have been published to date, so this broad assignment is based on the general archaeological context at each site. Our motivation was to see if a more precise chronology could be established by means of archaeomagnetic dating. Concomitant goals were to compare these results from Portugal to their counterparts in Spain and to expand geographic coverage of the regional geomagnetic secular variation reference curve. Experimentally, all the samples behaved in a very coherent manner during progressive alternating-field demagnetization and yielded high-precision mean archaeomagnetic directions (a95<3°) for each site. The results suggest that two of the kilns, Castelo de Vide and Peniche, were most likely in use during the late 1st/early 2nd centuries CE, whereas the two kilns at Seixal are somewhat younger, dating to the late 2nd to early 4th centuries CE.

Provenance analysis of human cremations by 87Sr/86Sr isotopic ratios: migration into an Iron Age mining region in North-Rhine Westphalia

The Siegerland (North-Rhine Westphalia, FRG) is famous for its early mining industry and ore exploitation. The archaeological context of cremated burials as well as grave goods indicate parallels to today's Wetterau (Hesse), suggesting migration into the Siegerland. After morphological examination of the cremations augmented by a histological age-at-death determination, provenance analysis by use of stable strontium isotope analysis was carried out. 60 individuals from the burial mound at Netphen-Deuz in the Siegerland were available for anthropological examination. The 87Sr/86Sr isotopic ratio was measured in 29 dentine and 15 bone samples. At least 19 individuals exhibited a non-local isotopic signal which was compatible with a provenance from the Wetterau region. Since 87Sr/86Sr isotopic ratios in the bioapatite are thermally stable, provenance analysis of cremated finds is thus possible, whereby a testable archaeological hypothesis is prerequisite. Histological examination of cremated bones proved indispensable for the age-at-death estimation.

Expect the unexpected: the vital need for wild plants in a Bronze Age farmer’s diet

Wild plant gathering and consumption has previously been described as being unimportant during the Bronze Age in the western Netherlands. It was believed that the people were full-time farmers and that the food produced on the settlement was enough for people to be self-sufficient. However, the analysis performed here to re-evaluate this statement has shown that wild plants were also essential to life in the Bronze Age. The combined information obtained from ethnography, ethnobotany, archaeology, ecology, nutritional studies, and physical anthropology has indeed indicated that wild plants, and especially their vegetative parts, would have had to have been gathered yearround in order for people to remain healthy.

Just a crush? Contamination of archaeological samples by different grinding media

A chert cobble from an archaeological quarry on southern Baffin Island, Canada, was divided and crushed using five different methods: i) agate mortar and pestle, ii) stainless steel shatterbox, iii) tungsten carbide shatterbox, iv) alumina ceramic shatterbox, and v) zirconia ceramic shatterbox. Powders produced by each method were submitted for acid digestion and analysis by inductively coupled plasma mass spectrometry. The trace element results indicate that different crushing media can contribute significant trace element contamination to chert during the grinding process. These results demonstrate the need for an informed approach to the selection of sample preparation methods when submitting archaeological samples for solution or pellet based geochemical analysis.

Marble provenance investigation of the Roman Sabine sarcophagus

The provenance of marbles used for making sarcophagi during the Roman period is an important question and scientific analysis can provide a strong confirmation and basis for future studies determining when and where the materials were obtained for manufacture. By using three different techniques (<em>i.e.</em>, electron paramagnetic resonance spectroscopy, stable isotope analysis and maximum grain size measurements) plus <em>in situ</em> examination, it is possible to resolve fully the provenance and date range of the ancient marble.

Characterisation of copper alloy antique ornamental accessories found in Northern Albania

This study was performed to determine the chemical elements used to produce ancient metallic alloys and to understand the manufacture technique of three archaeological founds. It also presents an evaluation method of the objects’ authenticity based on the observation of the corrosion products. This article also includes three ornamental accessories ca. VII-IV century BC found in the vicinity of Shkodra (Albania). A necklace, a belt application and a button are examined using X ray fluorescence (XRF) to determine the chemical composition and optical microscopy (OM) with reflected and polarised light in order to study the microstructure and the corrosion products. From the XRF results all the objects are bronze, copper-tin and copper-tin-lead alloys. After the OM analysis they are authentic objects (not fake replicas) and might have been produced after a casting process in moulds.

The dynamic celestial Native American calendar of Devil’s Den Gettysburg, Pennsylvania, USA

Gettysburg’s legacy is a well-chronicled highlight of American history. However, its significance as a revered battleground overshadows a forgotten Iroquoian group (Susquehannock) that occupied the region. The battlefield contains a diabase outcrop known as Devil’s Den that displays rounded blocks and weathered rectangular joints. Field reconnaissance identified a leaning rock slab that forms openings aligned to the summer and winter solstices. Moreover, the rock openings align with the rising and setting of Pleiades and Sirius, respectively, stellar objects tracked by northeastern Native Americans for agricultural and religious purposes. A petroglyph-bearing rock shadowed by the slab is the first known occurrence of petroglyphs in Adams County and only the 22nd documented case in Pennsylvania. Petroglyphs relating to select cardinal directions, Ursa major, and Manitou (Great Spirit manifestations) were situated for sunlight to interact with them during certain times of the year. The discovery of an Iroquoian calendar implies the region was utilised by a sedentary society.

Thermal characterisation of Bronze Age hearths from the cave of Les Fraux (Dordogne, France) by thermoluminescence and magnetic susceptibility techniques

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.

Prehistoric pigment characterisation of the Abri Pataud rock-shelter (Dordogne, France)

Iron oxide pigments found in archaeological context constitute an important source of information for the understanding of cultural and subsistence activities of ancient human cultures. In order to complete archaeological contextual information, many analytical methods have been applied to characterise pigments and to provide further information on this material (<em>e.g.</em> supplies, selections, mechanical or physical transformations of raw material, use and application processes). Several studies have demonstrated that the elemental composition of iron oxide pigments can be used to discriminate between several geological provenances. In this study, non-destructive micro-particle induced Xray emission analysis was applied in order to distinguish different kinds of reddish pigments from the prehistoric site of Abri Pataud, more especially from the Layer 2 attributed to Final Gravettian period (22,000 BP). By using an external beam, this technique required no sampling, and enabled us to perform localised analyses directly on raw material, on ochre residues applied on artefacts or on fragments of the wall of this rock-shelter. The results obtained by this technique demonstrate that the pigments covering the decorated fragments of the rock-shelter wall, found during the excavation of the Layer 2, have elemental compositions similar to the composition of a raw pigment found in the same layer. These results suggest that the shelter was decorated during the Final Gravettian period and thus provide new insights for the understanding of the archaeological context of this occupation layer.

The metal production at Düzen Tepe (Southwest Turkey): an archaeological and archaeometric study

At the Classical-Hellenistic settlement at Düzen Tepe (SW Turkey), magnetite particles were observed in the majority of the excavation contexts and a considerable amount of metal production waste and metal objects was found in a wide variety of archaeological contexts. In order to find out the origin of the magnetite ore and to determine whether or not the ores, production waste and objects all originated from local metal production activities, a series of archaeological and archaeometric studies were executed. A petrographic study of production waste samples and X-ray fluorescence analysis of production waste and a magnetite ore sample indicated that indeed magnetite was used in the process from which the waste samples resulted. Several inherent characteristics of the magnetite sample used in this study, are likely reflected in the production waste samples. Through a combination of geomagnetic survey and archaeological test soundings a couple of areas probably related to iron production activities could be determined. One location was identified as an area for ore preparation. Although mutual links could not be determined for all three find categories related to metal production (ore, production waste and objects), the study yielded sufficient arguments to assume that metal was produced locally, local magnetite sources were exploited for that reason and at least part of the metal finds from the excavations resulted from that local production.