Copper Mines,Chromite Copper Ores and Slags of the Ishkinino Bronze Age Archaeological Microregion,The Southern Urals

The study addresses copper mines structure and composition of copper ores and slags at the Ishkinino archaeological microregion, Orenburg Province. Both ores and slags contain chromites derived from the host ultrabasite rock. Chromites were subdivided into three categories in terms of Cr2O3 content: 45–50%, 50–55%, and 55–61%. The proportions are similar to those observed in chromites of the malachite ores of the Ishkinino cobalt-copper-pyrite deposit. The reguli found in the slag contain copper sul?des and iron phosphides with a high content of nickel. Our results evidence the exploitation of local copper mines in the Late Bronze Age. Finds of chromite ores and slag at the archaeological sites of the Southern Urals are listed, and goals for future research are outlined.     

3D modelling of magnetic data from an archaeological site in north-western Tlaxcala state,Mexico

In Archaeology, geophysical methods had been applied usually in a qualitative form, limited only to the use of filters that enhance the data display. The main objective in this work is the implementation of a modelling technique that allows us to reconstruct the geometry of buried bodies and the determination of their depths. This is done by means of the estimation of the magnetic moments of archaeological objects using a three-dimensional mesh of individual magnetic dipoles using the least squares method and the singular value decomposition of a weighted matrix to solve the linear problem. The distribution and shape of the underlying archaeological remains can be inferred. This methodology was applied to an archaeological site called Los Teteles de Ocotitla, in the state of Tlaxcala, Mexico. A high-resolution magnetic prospection was carried out in three selected areas (terraces). The most important total field anomalies found on each area were inverted, obtaining results that were corroborated by archaeological excavations. This investigation demonstrates the potential of quantitative geophysical methods for the characterization of archaeological structures, in extension and in depth.     

Late Bronze Age Copper Smelting Slags from Luserna (Trentino,Italy): Interpretation of the Metallurgical Process

In the Late Bronze Age, the extractive metallurgy of copper in north‐eastern Italy achieved a peak of technological efficiency and mass production, as evidenced by the substantial number of metallurgical sites and the large volume of slags resulting from smelting activities. In order to define the technological features of the Late Bronze Age metallurgical process, more than 20 slags from the smelting site of Luserna (Trentino, Italy) were fully analysed by means of optical microscopy, X‐ray powder diffraction, X‐ray fluorescence spectrometry and scanning electron microscopy. Three different slag types were identified based on mineralogical and chemico‐physical parameters, each being interpreted as the product of distinct metallurgical steps. A Cu‐smelting model is proposed accordingly.     

THE USE OF TRACE ELEMENT ANALYSIS OF ENTRAPPED SLAG INCLUSIONS TO ESTABLISH ORE – BAR IRON LINKS: EXAMPLES FROM TWO GALLO‐ROMAN IRON‐MAKING SITES IN FRANCE (LES MARTYS,MONTAGNE NOIRE,AND LES FERRYS,LOIRET)*

Knowledge of the iron trade in ancient times rests on determining the source of the objects recovered during archaeological excavations. Unfortunately, attributing the origin is not always possible using archaeological tools alone. Trace element data of the ore and the archaeological material (reduction and reheating slags, entrapped slag inclusions from the bloom, bar iron and iron blades) from two Gallo‐Roman iron‐making centres, Les Martys (Montagne Noire) and Les Ferrys (Loiret), were determined using ICP–AES/MS and LA–ICP–MS. The results highlight a continuity of composition that makes it possible to establish a link between the initial ore and the semi‐finished iron products.     

Determination of the influence of soil parameters and sample density on ground-penetrating radar: a case study of a Roman picket in Lower Bavaria

Ground-penetrating radar (GPR) surveys are very much influenced by the site-specific physical properties, soil parameters and the sample density of the radar pulses. According to the electromagnetic theory, the transmission and reflection of electromagnetic waves is dominated by the conductivity, dielectric permittivity and the soil moisture. Therefore, it is advisable to measure these parameters in advance of a GPR survey. Commonly, this is not possible directly with the standard common-offset GPR arrays. To overcome this problem, we adapted and applied a direct method called time-domain reflectometry to a selected case study of the Roman picket Hienheim at the Raetischer Limes in Lower Bavaria. Furthermore, we present some important results relating to the profile spacing and orientation of GPR surveys and the site-specific soil parameters. The location and the identification of the archaeological features were successful by all geophysical methods. However, the application of all these geophysical methods like magnetometry, resistivity and GPR in addition with aerial photography and Airborne Laserscanning exemplifies the advantages of an integrated survey to achieve a comprehensive result of an archaeological site. The Roman picket of Hienheim shows up differently in all results, as each one traces the archaeological remains according to a specific physical parameter. Resistivity and radar are best to resolve buried stone structures like the walls of the picket or stone-filled ditches. In contrary, magnetometry benefits of the magnetic contrast between the limestone walls and the surrounding soil.     

Electric and magnetic tomographic approach for the geophysical investigation of an unexplored area in the archaeological site of Pompeii (Southern Italy)

The joint application of electric and magnetic techniques for near-surface exploration represents a very useful tool for archaeological investigation and can provide a quantitative contribution to describe the spatial distribution of buried objects. In this work we show a new advanced tomographic approach, based on the parallel inversion of magnetic and electric observed data, aimed at the reconstruction of the subsoil of a still unexplored area of the archaeological site of Pompeii (Southern Italy). The survey was performed in collaboration with Pompeii's Archaeological Commission. The comparison between the results obtained from the tomographic inversions of both electrical and magnetic data was carried out in terms of the data inversions, which allowed us to obtain information about the location of the buried geophysical sources in the investigated subsoil. The results obtained seem to be in a good agreement, both for the position of the geophysical sources and for their dimensions.     

Marine electrical resistivity tomography for shipwreck detection in very shallow water: a case study from Agropoli (Salerno,southern Italy)

A marine electric resistivity survey was carried out over a submerged beach along the Agropoli shore (Salerno, Italy) to detect buried objects of archaeological interest below the sandy seabed. We found a shipwreck, a military vessel that probably sunk during the Salerno landing operations of the allied forces in the Second World War. Resistivity data provide information on the vertical and horizontal extension of the shipwreck, which is characterized by very low calculated resistivity values (about 2–5 ohm m). Such values differ significantly from the sand and the bedrock values (5–40 ohm m). Although the presence of the shipwreck is clearly visible from geoelectric data, the joint application of electric, magnetic and multibeam bathymetric techniques reduces the ambiguities inherent in each method. As shown in the Electrical Resistivity Tomography (ERT) and confirmed by the Digital Elevation Model (obtained from the processing of bathymetric data), the shipwreck extends more than 30 m in NE–SW direction and it is about 13 m wide. The global extension of the relic is consistent with the magnetic data, that are characterized by a magnetic anomaly with an amplitude of about 1800 nT and similar dimension, as inferred from the estimation of source boundaries obtained from the computation of the analytic signal. The results of our survey encourage the use of marine geoelectrical methods for the detection of buried archaeological targets, particularly in locations where the use of seismic prospecting is not effective (e.g. very shallow water with sandy sea-bottoms). The integration of different geophysical methods allows to better define the extension, depth and thickness of buried objects, suggesting that such an approach is the most effective for underwater archaeological investigations.     

电磁法在三星堆遗址祭祀区中的探索与应用

自2019年12月,三星堆遗址启动全面的勘探工作,相继在祭祀区新发现6座祭祀坑,为制定科学的考古发掘及文物保护预案,需在考古发掘之前对地下文物有一定的了解。根据一号、二号坑出土物情况,以金属埋藏物为探测对象,使用地球物理勘探方法中的电磁法先期通过实验获取经验值,然后再对祭祀区进行详细探测,并与实际发掘结果比对,说明电磁法对青铜器探测具有一定的可行性,可为前期考古发掘提供重要的参考信息。     

Indigenous African Furnace Types and Slag Composition—Is there a Correlation?

Within variation, three major iron smelting furnaces were used in the Iron Age of sub‐Saharan Africa, ranging from the natural draught driven tall shaft to the forced draught powered low shaft and bowl furnaces. These furnace types are, however, mostly known from the ethnographic context. Often, archaeologists are confronted with remnants from the smelting process, forcing them to speculate on the anatomy of the extant furnaces. The presence of multiple fused tuyeres has been used to identify natural draught furnaces in the archaeological record. However, working back from smelting remains such as slag to the furnace type using physical and chemical evidence has generally proved to be ‘undoable’. Thus, when randomly selected, the chances are high that one cannot separate bowl furnace slags from those that formed in their tall or low shaft counterparts. This observation is hardly unexpected; analogous thermodynamics and thermo‐chemical reactions governed bloomery smelting irrespective of furnace type. Rehren et al. (2007) have labelled this phenomenon the ‘tyranny of system driven constraints’. In this study, we argue that the hierarchical use of statistical methods may add another layer of evidence which, when coupled to archaeological indicators, may be useful in correlating slag chemistry to furnace types used in antiquity.     

The technology of tin smelting in the Rooiberg Valley,Limpopo Province,South Africa,ca. 1650–1850 CE

A substantial indigenous tin-smelting industry arose in the Rooiberg valley of northern South Africa in the second millennium CE. This study concentrates upon tin-smelting slags and refractory ceramics from two archaeological sites that date between ca. 1650 CE and ca. 1850 CE. These were studied by optical and electron microscopy, wavelength-dispersive x-ray fluorescence (WD-XRF), inductively-coupled plasma mass spectrometry (ICP-MS), and electron microprobe (EMPA). The slags are predominantly glassy; high SnO and relatively low SiO₂ contents indicate that tin is a major glass-forming element. Comparison of slag chemistries with the mineralogy of ore deposits and host rocks shows that alluvial cassiterite was used at one of the sites, while cassiterite from hard-rock mining was smelted at the other site. Since few preindustrial tin slags have been studied, we compare our findings to other published examples, mostly from southwest England.     

Integrated geophysical surveys at the archaeological site of Tindari (Sicily,Italy)

The results of geophysical survey carried out at the archaeological site of Tindari, located 70 km west-north-west of Messina (Sicily, Italy), are presented and discussed. The site is one of the most important archaeological sites, about 90 ha large, on the north-eastern side of Sicily and it was one of the last Greek settlements in Sicily. Keeping in mind the vastness of the site, according to the archaeologists an area, of about 1200 m² was selected, for a geophysical survey. Electrical resistivity tomography (ERT), including induced polarization (IP) measurements, and seismic refraction tomography were applied in the course of geophysical exploration in the area. The objective of this preliminary geophysical investigation was to verify the effectiveness of the technique for a spatial definition of the buried archaeological structures (mostly walls, columns, etc.) to determine their characteristics and to study the presence of collapsed columns within the zone of archaeological interest, in view of their application in the rest of the site, that, for obvious reasons, could not be entirely excavated in brief times. The geophysical data, visualized in 3D space, revealed a distribution of low-contrast shallow anomalies that indicate the presence of different types of buried structures in the surveyed area. Also, the probable accumulations of collapsed columns could be determined. These results confirm the hypothesis of a large northern extension of the archaeological site and provide useful information to design a more efficient excavation plan.     

Integration of geophysical surveys,ground hyperspectral measurements,aerial and satellite imagery for archaeological prospection of prehistoric sites: the case study of Vésztő-Mágor Tell,Hungary

An integration of geophysical surveys, ground hyperspectral data, aerial photographs and high resolution satellite imagery for supporting archaeological investigations at the multi-component Vészt?-Mágor Tell, located in the southeastern Great Hungarian Plain, is presented in this study. This is one of the first times that all these techniques have been combined and evaluated for retrieving archaeological information. Geophysical explorations, specifically magnetic gradiometry and ground penetrating radar methods, have revealed shallow linear anomalies and curvilinear rings at the Tell. The use of remote sensing images has confirmed the diverse anomalies with respect to geophysics through photointerpretation, radiometric and spatial enhancements. Moreover, several indices from ground hyperspectral data also have revealed stress vegetation anomalies. These integrated results were used to map the main areas of archaeological interest at the Vészt?-Mágor Tell and plan future excavations. It was found that these multiscalar data can be used efficiently for detecting buried archaeological features.     

Geographic Visualization in Archaeology

Archaeologists are often considered frontrunners in employing spatial approaches within the social sciences and humanities, including geospatial technologies such as geographic information systems (GIS) that are now routinely used in archaeology. Since the late 1980s, GIS has mainly been used to support data collection and management as well as spatial analysis and modeling. While fruitful, these efforts have arguably neglected the potential contribution of advanced visualization methods to the generation of broader archaeological knowledge. This paper reviews the use of GIS in archaeology from a geographic visualization (geovisual) perspective and examines how these methods can broaden the scope of archaeological research in an era of more user-friendly cyber-infrastructures. Like most computational databases, GIS do not easily support temporal data. This limitation is particularly problematic in archaeology because processes and events are best understood in space and time. To deal with such shortcomings in existing tools, archaeologists often end up having to reduce the diversity and complexity of archaeological phenomena. Recent developments in geographic visualization begin to address some of these issues and are pertinent in the globalized world as archaeologists amass vast new bodies of georeferenced information and work towards integrating them with traditional archaeological data. Greater effort in developing geovisualization and geovisual analytics appropriate for archaeological data can create opportunities to visualize, navigate, and assess different sources of information within the larger archaeological community, thus enhancing possibilities for collaborative research and new forms of critical inquiry.     

An assessment of the magnetic response of an iron‐smelting site*

The magnetic response derived from an iron‐smelting site was investigated by comparing magnetometry and magnetic susceptibility geophysical survey data and laboratory analyses of the magnetic characteristics of the furnace and slags. Magnetic analysis and microscopy (optical and SEM) of samples from the furnace lining and the slag deposits demonstrated the heterogeneity in the magnetic, morphological and mineral compositions of both materials. The comparison of the magnetic characteristics of the material with the geophysical survey data illustrated the importance of using both magnetometry and magnetic susceptibility survey techniques to maximize the information from an iron‐smelting site. The furnace was dated archaeomagnetically to the 14th century ad . The results demonstrate that the magnetic analysis of iron‐smelting sites is highly valuable, both to characterize sites and to improve the understanding of early iron‐working technology.     

Large-Area Remote Sensing Coverage of Archaeological Sites with a Dual-Track Cart-Mounted Cesium Magnetometer

Abstract

This paper describes the benefits of collecting total field magnetic data at archaeological sites with a mobile cart holding two cesium magnetometer sensors and a separate stationary base station magnetometer to correct for global-scale magnetic fluctuations. To date, the Texas Historical Commission has surveyed 40 sites from various time periods and geographical settings in Texas. The cart has allowed rapid surveys over large areas while minimizing signal-degrading noise. Four examples from Texas show that large-area and high-density magnetic surveys can be completed in relatively short periods of time producing maps that aid significantly in archaeological site interpretation. In some instances, no field excavation was required to understand quickly what the magnetic patterns represented in terms of buried archaeological features. In all cases, the magnetometer maps provided important information to help guide future field excavations.     

DATING ARCHAEOMETALLURGICAL SLAGS USING THERMOLUMINESCENCE*

Thermoluminescence has a great potential for dating archaeometallurgical slags, because the smelting process leads to a well‐defined resetting of the ‘luminescence clock’. However, the complex compositions of slags have unpleasant consequences for TL measurements if the bulk slag substance is used. To overcome this problem, quartz has been separated out of slag matrices by chemical and physical procedures. The TL measurements were carried out on this defined mineral phase. This method was tested with seven slag samples from different locations and ages. In most cases, the TL ages determined show good agreement with reference data.     

Multi-element soil prospection aiding geophysical and archaeological survey on an archaeological site in suburban Sagalassos (SW-Turkey)

In order to take full advantage of the archaeological information contained within buried archaeological sites, it is important to apply an integrative approach combining complementary prospection methods. In this study, geochemical prospection data are combined with archaeological and geophysical survey results on an unexcavated site in suburban Sagalassos (SW-Turkey), with the aim of obtaining better insights into the structural shapes and past functionalities of the area. Spatial and multivariate statistical analyses of the chemical data reveal anomalies of K, P and Zn on a location where archaeological and geophysical results suggest the presence of ceramic producing kilns. These elemental enrichments are thought to result from burning wood or dung as fuel for the detected kilns. In addition, local anomalies of Co, Cr, Fe, Mg, Mn and Ni were found to reflect the working and storage of ophiolitic clays, employed as a raw material for ceramic production. Radiocarbon dating of charcoal in a 2.5 m deep drill core in this zone provides ages between AD 120 and 350 at depths of 50 and 60 cm. Al, As, Ba, Ca, Na, Sr, Ti and Pb are considered geogenic elements in this study. The present study supports the theory that geochemical prospection holds potential as a surveying technique, as it was found that chemical data facilitate the interpretation of structures detected by geophysical and archaeological methods, thereby creating an extra dimension to the interpretation of survey data. The results further argue in favour of using strong-acid extractions and the consideration of a large suite of elements when applying chemical soil survey as an archaeological prospection technique, and highlight the importance of considering site lithology. Multivariate statistics proved to be invaluable in distinguishing anthropogenic from lithological soil patterns.     

THE INFLUENCE OF GEOLOGY ON THE MAGNETIC SUSCEPTIBILITY OF SOILS ON ARCHAEOLOGICAL SITES

A heating mechanism for the enhancement of the magnetic susceptibility of soils on archaeological sites is assumed. Data for the iron oxide concentration which is available for conversion to the strongly ferrimagnetic form is presented for soils derived from a wide range of geological strata. These data are then used, in conjunction with the concept of the fractional conversion of the iron oxide that has occurred as a result of fires associated with human habitation, to explain the wide range of soil susceptibilities observed on archaeological sites. The feasibility of employing magnetic surveying techniques for the location of buried features on archaeological sites, situated on the different geological strata, is then discussed.