A new protocol for the chemical characterisation of steatite – two case studies in Europe: the Shetland Islands and Crete

Steatite has been one of the most difficult materials of archaeological interest to characterise by physico-chemical methods of analysis with a view to identifying its origin. This paper presents a new protocol for the chemical characterisation of steatite based on the analysis by ICP-MS in tandem with INAA of rare earth elements (REE) and some transition metals in geological steatite from several outcrops on the Shetland Islands and on Crete. The major advance over earlier work has been the secure determination of REE at low concentrations. The results have demonstrated the ability to discriminate chemically three of the known Viking Age sources on Shetland. On Crete, although the situation is complex, four sources in the centre of the island have been partially differentiated. This study has also shown that first mineralogical analysis (by XRD) of steatite provides valuable supplementary characterisation data, and second strontium isotope analysis has promising potential for the sourcing of steatite.     

STEATITE SOURCE CHARACTERIZATION IN EASTERN NORTH AMERICA: NEW RESULTS USING INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS*

Doubts have recently been cast on the ability to characterize steatite sources using rare earth elements (REEs). By increasing the number of samples and elements examined using instrumental neutron activation analysis (INAA) and multivariate statistics, this study shows that, with unhomogenized samples, transition metals, not REEs, make the greatest contribution in characterizing steatite sources in the Middle Atlantic region of eastern North America. Preliminary results suggest that INAA has the potential to assign provenance to steatite artefacts, at least at a regional level.     

RESEARCH NOTES AND APPLICATION REPORTS ELEMENT DISTRIBUTION MAPS IN FOSSIL BONES

The combined application of fission track analysis and neutron activation-induced β-autoradiography to map the trace element distributions of scandium, cobalt, uranium and rare earth elements in fossil bone samples from East Africa is described. Both uranium and the rare earth elements are incorporated into bone apatite during fossilisation, whereas scandium and cobalt occur additionally in any iron-manganese minerals precipitated in pore spaces within the bone cortex. The distribution of uranium is different from that of the rare earth elements in the fossil bone cortices; it enters fossil bone more rapidly and is sensitive to changes in the redox potential of the palaeogroundwater.     

THE APPLICATION OF INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS TO A STUDY OF PREHISTORIC STEATITE ARTIFACTS AND SOURCE MATERIALS

A study of the trace and minor element content of steatite artifacts from the Eastern United States has been carried out. Samples from both quarry and habitation sites ranging from New York to North Carolina have been analyzed through the use of instrumental neutron activation analysis. The most successful method of evaluating data has involved the study of a very coherent group of elements known as the Rare Earths. Geological processes cause fractionation of this group and it is this fractionation which is of use in terms of characterizing the source deposits of this material. Promising but less definitive results have been obtained with the elements scandium, chromium, cobalt and others. Sufficient variations have been found to be present in the source deposits of steatite in this area to enable differentiation, and the successful linking of samples from habitation sites to their quarry deposits has been achieved in some cases. This paper discusses the results of this study to date, the methods employed, and the potential value of this work in helping to reconstruct prehistoric trading systems.     

DISCRIMINATING SOURCES OF MEDITERRANEAN MARBLES: A PATTERN RECOGNITION APPROACH

A computer-based pattern recognition procedure has been applied to trace element data obtained from marble samples of different Mediterranean quarries. Nineteen elements, mostly hydromagmatic and rare earth elements were first determined by neutron activation analysis. These elemental concentrations are then used as the data for further multivariate analysis. The results indicate significant differences in chemical patterns of the marble sources.     

Quantitative EDXRF Studies of Obsidian Sources in Northern Hokkaido

Quantitative trace element data from six obsidian sources on the Japanese island of Hokkaido is presented. Previous work by Japanese scholars has utilized neutron activation analysis (NAA) focusing on the rare earth elements, or qualitative energy dispersive X-ray fluorescence (EDXRF). In this study, non-destructive EDXRF is used to generate trace element data for 9 elements. Bivariate plots of the incompatible trace elements (Ba, Rb, Sr, Y, and Zr) can be used to separate the obsidian sources in this study. Source separation was confirmed by using linear discriminant analysis. Stepwise discriminant analysis indicates that Ba, Sr, Rb, Ti, Y, and Zr are the most discriminating elements.     

Changes in chemical composition caused by water–rock interactions across a strike‐slip fault zone: case study of the Atera Fault,Central Japan

In some cases, water–rock interactions in fault zones can affect radionuclide migration. Here, we analyzed the chemical compositions of well‐exposed fault rocks from the strike‐slip Atera Fault, Central Japan, in order to understand the variability and behavior of major and selected trace elements. The fault zone has a 1.2‐m‐wide, smectite‐rich fault core and paired damage zones that developed within welded tuff on one side of the core and within granite on the other side. The 30‐cm‐wide, kaolinite‐rich fault gouge is developed in granite cataclasite, and it shows indications of the latest fault activity, while the 1.2‐m‐wide fault core appears to be older. Hydrogen and oxygen isotope ratios in the clay‐rich fault gouges, and carbon and oxygen isotope ratios in carbonates indicate that the two major clay‐rich zones formed in bedrock near the surface, consistent with observed deformation structures. Based on chemical analyses, we identified (1) a slight depletion in SiO₂, Na₂O, K₂O, and light rare earth elements at the edges of the 1.2‐m‐wide fault core, (2) a clear depletion in SiO₂, Na₂O, K₂O, and all rare earth elements except Eu in the 30‐cm‐wide fault gouge, and (3) an increase in CaO, MnO, and heavy rare earth elements across the entire 1.2‐m‐wide fault core. Findings (1) and (2) reflect water–rock interactions in the 1.2‐m‐wide fault core and in the 30‐cm‐wide fault gouge that resulted in the formation of smectite and kaolinite. Finding (3) reflects carbonate precipitation caused by the addition of basalt fragments from a nearby site to the 1.2‐m‐wide fault core during faulting, and subsequent sorption reactions of heavy rare earth elements via processes such as complexation with the carbonates.     

DATA ON 61 CHEMICAL ELEMENTS FOR THE CHARACTERIZATION OF THREE MAJOR GLASS COMPOSITIONS IN LATE ANTIQUITY AND THE MIDDLE AGES

Sets of 20 soda ash, 16 soda lime and 23 wood ash glasses mainly from excavations in Europe were analysed by microprobe and LA–ICP‐MS for 61 elements and are presented as average concentrations with standard deviations. Concentrations of sodium, potassium and magnesium allow the major glass type to be identified. Specific compositions of the raw materials of glass production indicate certain sources, technical processes and ages. Heavy minerals etc. of quartz sands contain rare earth elements (REE) from crustal fractionations that are different for the three major glass types. Accumulations of P, B, Ba, Mn and K in wood from soils by organic processes can characterize glass from certain regions.     

Sourcing Iron Age softstone artefacts in southeastern Arabia: results from a programme of analysis using Inductively Coupled Plasma-Mass Spectrometry/Optical Emission Spectrometry (ICP-MS/OES)

Iron Age softstone vessels manufactured in southeastern Arabia are widely distributed across that region and in lesser amounts throughout Western Asia. Results from a pilot programme of analysis using Inductively Coupled Plasma Mass Spectrometry/Optical Emission Spectrometry on vessel fragments from two southeast Arabian sites are presented. These results indicate the existence of geochemically distinct groups that are separated by both transition metals and rare earth elements. While this indicates the potential for the application of the provenance postulate in softstone analysis, these promising results need to be further tested by an expanded programme of analysis which includes quarry fragments.     

Deciphering the inorganic chemical record of ancient human activity using ICP-MS: a reconnaissance study of late Classic soil floors at Cancuén,Guatemala

Inorganic chemical analysis of soil floors using inductively coupled plasma-mass spectrometry (ICP-MS) was undertaken to provide information on the nature and location of past human activity in the ancient Maya city of Cancuén, Guatemala. The use of ICP-MS to detect trace and ultra-trace elemental enrichment of two excavated soil floors from the late Classic period is the first study of its kind in Mesoamerican archaeology. Geochemical background of the site was established by the analysis of palaeosols and nearby undisturbed ‘off-site’ soil profiles. Robust statistical methods used in the study clearly distinguished the level of anthropogenic enrichment across the former floors. Many elements measured showed only minor departures (10–20%) from the site's background soil chemistry. The greatest levels of elemental enrichment were detected in the rare earth elements, mercury, and gold. The latter is of particular interest considering the consensus that gold was absent from the world of the Classic-period Maya. Comparisons of the spatial pattern of mercury enrichment with lithic and archaeological data show strong linkages to past industrial and ritual activities. Elevated rare earth element concentrations were recorded broadly across both soil floors and are considered to be related to concentrated human occupation in antiquity.     

三峡出土宋元青白瓷产地的判别

为研究重庆地区三峡工程抢救性发掘出土了一批宋元时期青白瓷的产地,采用中子活化方法,分析了28枚三峡出土宋元时期的青白瓷残片和20枚时期相近、窑口已知的青白瓷残片,利用SPSS软件对上述样品胎体的微量元素数据进行统计分析.结果发现:江西产青白瓷的稀土元素含量与福建、安徽、湖北等地差异显著,而Rb、Cs、Hf、Th等微量元素含量也明显不同;三峡出土的青白瓷样品中,除编号为荣阳5和涂山窑5这两枚残片外,其余残片的元素特征与景德镇所产青白瓷颇为一致,拟断定这些青白瓷源自景德镇.     

THE UTINKA BURIAL

New Middle Bronze Age fi nds are described originating in the Achinsk-Mariinsk forest-steppe, southwestern Siberia which represents a contact zone between the Okunev and Samus cultures. A burial discovered near Lake Utinka by local inhabitants, northeastern Kemerovo region, was found to contain steatite beads and unusual pendants in the form of a bear and a bird. The subsequent fi eld survey revealed characteristics of the burial construction and fragments of clay vessels. The designs on the vessels suggest that the burial was associated with the Samus culture. However, their manufacturing technology and the features of the steatite beads indicate Okunev affi nities. Based on the totality of available evidence, it is suggested that contact existed between the Samus and Okunev cultures in the Achinsk-Mariinsk forest-steppe area.     

An Experimental Investigation into the Accidental Invention of Ceramic Glazes

Glazed objects, mainly in the form of glazed quartz and steatite solid stones, first appeared during the fifth millennium bc . At the present time, it is generally accepted that the accidental discovery of glazing was associated with ancient copper production. However, the replication experiments already conducted on glazed stones were unable to provide a convincing explanation for the accidental invention of ceramic glazes. This paper attempts to suggest a possible explanation for the accidental invention of glazes on solid stones (i.e., steatite and quartz) during the Chalcolithic period. A series of replication experiments were undertaken and the resulting objects were examined using SEM–EDS.     

A multivariate analysis of pottery from southwestern Cyprus using neutron activation analysis data

Neutron activation analysis is employed to geochemically characterize 129 pottery sherds collected from 38 sites during an archaeological survey of the Paphos District of southwestern Cyprus. Cluster analysis identifies three significant groupings using 26 trace elements and rare earth elements. These compositional groupings appear to reflect differences in the geographical locations of the sherd collection sites and particularly the influence of the surficial geology. In particular, the rocks of the ultramafic Troodos Ophiolite Zone, the Mamonia Complex, and various formations of the Circum Troodos Sedimentary Sequence appear to impart a detectable imprint on the sherds of the study area. Discriminant analysis identifies Ce, Th, Cr, Na, Fe, Hf, Ba and Co as the most significant chemical discriminators between the three compositional groupings and derives two discriminant functions that between them account for 100% of the variance between the groups. Discriminant analysis also confirms that 82% of the sherds classified by cluster analysis are correctly classified. Based on probability measures, the large majority of the sherds (98%) are considered to be local in origin.     

NEUTRON ACTIVATION ANALYSIS OF ARCHAEOLOGICAL MATERIALS: AN OVERVIEW OF THE ITN NAA LABORATORY,PORTUGAL

Instrumental neutron activation analysis (INAA) has been applied to archaeological samples at the Portuguese Research Reactor (RPI) since 1973, and the number of samples analysed has increased steadily since the mid‐1990s. Archaeometric applications of INAA at RPI include the analysis of archaeological ceramics and the stones used in monumental architecture (menhirs) and other historical monuments. A programme of analysis also exists for measuring the precision of and contributing to the certified values of geochemical reference samples. In addition, the study of interference factors is performed to obtain better accuracy in the determination of concentrations of some elements (e.g., corrections for spectral interferences from uranium fission products in the determination of barium, rare earth elements and zirconium).     

THE BROCH CULTURES OF ATLANTIC SCOTLAND. PART 2. THE MIDDLE IRON AGE: HIGH NOON AND DECLINE c.200 BC–AD 550

The basic features of broch architecture are discussed. There were probably a large number of classic, hollow-walled, dry-stone towers, as opposed to lower, less architecturally sophisticated 'Atlantic roundhouses'. Various kinds of dating imply that most were built – probably by professionals – in the Middle Iron Age, from c.100 BC to AD 200, although a few emerged earlier in Shetland, perhaps from 400–300 BC. Wheelhouses seem to have emerged from these early Shetland brochs. The MIA material culture includes many new items found all over the province, though much of the pottery is regional. Everted Rim ware was clearly connected somehow with the spread of the brochs from Shetland. The details of the MIA mixed farming economy are reviewed, as is the varied if indirect evidence for the social organization of the broch families; a hierarchical clan society is implied. The MIA now seems to have lasted until the sixth century AD and in the west at least its end may have been precipitated by a drastic climatic downturn.     

First Finding of Early Medieval Iron Slags in Sardinia (Italy): A Geochemical–Mineralogical Approach to Insights into Ore Provenance and Work Activity

At Santa Filitica, a Roman settlement in north‐western Sardinia occupied until the ninth century ad , archaeological excavations have found the remnants of a furnace consisting of a semi‐circular base made of stony slabs and tiles bound with clay. The furnace is attached to a wall of Roman age. Layers of the sixth century ad , bearing several variously oxidized slags, were found close to the furnace. These findings first testify to an ironworks in Sardinia, within a well‐defined context. XRPD and SEM–EDS mineralogical and textural analyses suggest that the slags derive from a bloomery and smithing work that was the first evidence of this type documented in Sardinia during the Early Middle Ages. Chemical analyses (performed with ICP and INAA) of rare earth elements and trace elements in two slags and in two Sardinian iron deposits allow some conclusions to be drawn on the local provenance of the ore. Our comparison of the Sardinian findings and some slags representative of archaeological smelting sites at the front of Elba island—the largest and longest lived iron‐working sites in the Mediterranean—also improves the methodology with which iron slags derived from different ores are compared.     

Main and trace elements in KTB-VB fluid: composition and hints to its origin

The pilot hole (VB) of the German Continental Deep Drilling Program (KTB) was drilled to a depth of 4000 m, where large amounts of free fluids were met. The KTB‐VB 4000 m fluid can be related to either Mesozoic seawater or formation water from Permo‐Carboniferous sedimentary rocks of the Weiden embayment. During the Upper Cretaceous uplift of the Bohemian Massif both fluids could have passed organic‐rich Triassic to Carboniferous formations of the Weiden embayment before invading the uplifted and fractured basement rocks of Devonian amphibolites and metagabbros, where the chemical composition of the fluids was changed by albitization, adularization, and chloritization. Results of chemical mass balances for both sources are presented. In order to concentrate the formation water from the Weiden embayment significant amphibolitization has to be assumed. During a 1‐year pumping test the chemical composition of the 4000 m fluids remained constant. The accuracy of chemical analyses is critically reviewed. An improved preconcentration method of rare earth elements and yttrium in high‐Ca‐bearing saline fluids is described.     

First discovery of ancient soft‐stone (chlorite) vessel production in Arabia: Aqir al‐Shamoos (Oman)

Soft‐stone vessels are a prominent feature of ancient culture throughout south‐east Arabia and the Gulf. Chlorite and steatite occur naturally in the al‐Hajar Mountains of the United Arab Emirates (UAE) and Oman; but until now, apart from the discovery of a few unfinished pieces, ancient production of soft‐stone vessels had yet to be documented in Arabia. This paper reports the discovery and preliminary analysis of soft‐stone vessel production at the site of Aqir al‐Shamoos. At this small and secluded mountain village, a range of soft‐stone vessels that are well known in the south‐east Arabian Iron Age were produced on a scale far beyond what was needed for local consumption.