Recent discoveries of rapid changes in the atmospheric
C concentration linked to solar particle events have spurred the construction of new radiocarbon annual calibration datasets
. With these ...datasets, radiocarbon dating becomes relevant for urban sites, which require dates at higher resolution than previous calibration datasets could offer. Here we use a single-year radiocarbon calibration curve to anchor the archaeological stratigraphy of a Viking Age trade centre in time. We present absolutely dated evidence for artefact finds charting the expansion of long-distance trade from as far away as Arctic Norway and the Middle East, which we linked to the beginning of the Viking Age at AD 790 ± 10. The methods developed here enable human interactions and cultural, climatic and environmental changes to be compared in archaeological stratigraphies worldwide.
High-definition approaches are currently revolutionizing our understanding of the archaeology of urban archives. Multi-proxy studies at a high spatial resolution offer especially an opportunity to ...capture their high data potential. Here we present a study of complex floor layers from an occupation phase dating to c. AD 790–830 uncovered in the Viking-age emporium Ribe, Denmark (c. AD 700–900). In order to better understand stratigraphy and the use of indoor space, mapping for soil geochemistry (portable X-ray fluorescence analysis, pXRF) on a high-resolution grid (0.25 × 0.25 m, n = 1059), was combined with targeted sampling for soil micromorphology and artefact distributions. The results show that the studied occupation phase was composed of several short-lived floor phases belonging to two consecutive houses that had been sampled in conjunction, and which exhibited a complex stratigraphy. The older house phase had a primarily domestic function, where ten functional areas could be defined, and are interpreted as designated spaces for food preparation, storage, sitting or sleeping, and weaving. A younger house phase contained a metal workshop in addition to domestic functions. Methodologically, a number of new, potentially anthropogenic, elements of archaeological interest, such as arsenic, manganese and sulfur, were identified that may contribute to interpretations, while the multi-proxy approach elucidates the refined scale at which we can understand a complex stratigraphic sequence and the integrity of its units. This study shows how the various aspects of Viking-age urban life (craft production, domestic life) were integrated, and sheds light on the dynamics of urban occupation.
Micro‐X‐ray fluorescence (XRF) screening of 244 glass sherds from Ribe, Denmark, identified 23 wood ash glasses. The closely dated finds pinpoint the arrival of the earliest wood ash glass produced ...in Western Europe in this important North Sea trading hub. This glass type was absent among glass from 700 to 790 CE but feature strongly from 790 to 810 CE. Electron microprobe analysis (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) analysis of 24 glasses show the presence of four types. We show the strengths of classifying wood ash glass based on the glass‐producing sands and conclude that the earliest production took place on a considerable scale and had a major impact on glass circulation in Northern Europe in the ninth century.
Recently, new augmented recording techniques have entered archaeological fieldwork. We review a major urban excavation in Ribe, Denmark, which has adopted a systematic use of 3D laser scanning and ...intensive soil and sediment micromorphological sampling as part of the excavation recording practice. Both methods represent a major advance in field documentation, achieving a higher degree of detail and precision for the recording of archaeological features. We aigue that these technologies also challenge the current paradigm of single-context recording, i.e. the separation of layers and features as all-encompassing units of recording. First, 3D digital recording implies that contexts are defined in a more definite way than previously, with less flexibility for recursive revision. Second, micromorphology demonstrates how the strata separated in excavation are only a subset of those created in deposition. We call for a new approach, which takes into consideration the fact that excavation units do not always mirror depositional events, as assumed by single-context theory, and that different kinds of observations may not overlap, as assumed in singlecontext practice. Instead, interfaces, matrices and assemblages are restored as separate units to record and feed into the interpretation cycle. This may be described as recording metacontext: observations that go across or between contexts. We demonstrate how a systematic metacontext registration can lead to a manageable and more detailed excavation record, more faithful to the archaeologists' observations.
Glass-bead production was a major craft industry in Northern Europe during the Early Middle Ages. This was a time characterized by a fragmentation of long-distance exchange networks in Eurasia, and ...of rapid change in raw glass production and distribution. We report results from glass recovered from two bead-making workshops within the trading emporium of Ribe, Denmark (eighth century CE). Ninety pieces of tesserae, vessel fragments, cullet, crucibles, workshop refuse and beads were analyzed for major and trace element by electron microprobe and laser ablation ICP-MS. Isotopic compositions were measured on thirteen samples for Sr and on six samples for Hf. For the Early workshop and contemporary material, the results demonstrate a use of recycled Roman and Late Antique glass including Egyptian HIMT, Foy 2.1 and Foy 3.2. White beads were made by remelting gold leaf tesserae at low temperature, creating bubbles and thus opaque white. Blue glass present as glass splinters is explained as melting blue tesserae together with mainly gold leaf tesserae thereby diluting Sb and Ca to obtain translucent glass by preventing crystallization of calcium antimonates. Vessel glass cullet is heavily contaminated Roman-type glass. The range of colours in the Late workshop shows evidence of glass mixing and addition of colourant for colours including black, red, green and yellow. Mixing of recycled glass with lead stannate in sherds from glass crucibles show that green and yellow colouring was carried out on site. Both workshops show a more complex processing from tesserae and cullet to beads than suggested by previous analysis.
This study explores the significance of spatial sampling resolution on portable X-ray fluorescence (pXRF) analysis of an archaeological settlement site with favorable preservation conditions and ...clearly defined stratigraphic contexts as a benchmark study to interpret geochemical mapping of anthropogenic elemental markers. We present geochemical elemental mapping of a Viking-Age house floor in Denmark based on an unprecedented sampling density of a 0.25-m grid. In order to establish a fast, cost-efficient, comparable approach of how different sizes of data resolution affect the spatial elemental patterns, the data is analysed using three different grid sizes: 0.25 m × 0.25 m, 0.5 m × 0.5 m, and 1.0 m × 1.0 m. We analysed each grid size with selected anthropogenic markers (CaO, Cu, P
2
O
5
, and Sr) using ordinary kriging. The CaO, P
2
O
5
, and Sr patterns display a strong inter-correlation between data points up to a distance of 1–1.5 m from one another. At the highest resolution (0.25-m grid), all of the elements display a high degree of detail in the variation of the elements across the indoor surface with low standard deviations. Hence, the precise position of hot and coldspots, and spread of bounded concentration zones, is easily recognized in the maps. With the low resolution (1.0-m grid), the borders between high and low concentrations become more blurred and the indications of smaller hotspots (possible activity areas) are completely lost. Especially, Cu displays a high degree of clustering, which the high-resolution sampling could best reveal. This benchmark study shows that it is realistic to perform large-scale geochemical surveys of archaeological settlements using pXRF spectrometry in a standard archaeological excavation context, but also that sampling distances of 0.5 m × 0.5 m or finer are best suited to in indoor contexts.
We present a pilot study using visible near-infrared spectroscopy (vis-NIRS) to investigate ancient geochemical activity signals from an excavation of the Viking-Age Ribe Emporia, Denmark. Our aim is ...to study whether vis-NIRS is applicable to archaeological soil analysis and if it can provide additional insight into the use of space inside houses. Using 1059 bulk soil samples sampled in a 0.25 cm grid, we test if vis-NIRS is useful for predicting magnetic susceptibility and anthropogenic elements such as Ca, Cu, P and Sr. Furthermore, we test both portable X-ray fluorescence (pXRF), magnetic susceptibility and bulk chemistry (by inductively coupled plasma mass spectrometry, ICP-MS) as reference data for training the vis-NIRS models. Predictions were performed using a partial least squares (PLS) regression with a non-linear iterative partial least squares (NIPALS) algorithm, and the best cross-validation predictions for each element based on both portable pXRF and ICP-MS as well as predictions for magnetic susceptibility were analysed spatially using ordinary kriging. The spatial analysis showed reduced precision for all elements and magnetic susceptibility compared to reference maps. Additionally, the spectral predictions had difficulties in predicting the entire elemental and magnetic susceptibility range and especially struggled with the prediction of hotspot areas. Elemental predictions based on the two different reference datasets, collected with pXRF and ICP-MS, performed equally well. The more cost-efficient approach was pXRF for calibration data. Further development is needed for the application of vis-NIRS to be fully implemented together with geochemical tools as a regular part of archaeological soil analysis on site.
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