Factors Determining Magnetic Enhancement of Burnt Clay from Archaeological Sites

The magnetic susceptibility of a collection of 212 archaeological samples of burnt clay of different origin (burnt soil, ovens and bricks) taken from 60 archaeological sites from Bulgaria, were studied in order to determine factors which may have affected their magnetic enhancement. The highest magentic susceptibility values were obtained for bricks, and the lowest for burnt soils, suggesting that the firing temperature and the duration of burning are important conditions for determining magnetic enhancement. Specific spatial pattern of the low-field magnetic susceptibility was also observed, characterized by separation of sites situated in northern and southern parts of the country, divided by the west-east trending mountain chain Stara Planina. Maximum susceptibility values are obtained for burnt soils in southern Bulgaria and minima in northern Bulgaria. In contrast, burnt clay plasters and bricks show the opposite picture. It is supposed that the observed pattern is due to differences in the outcropped geological formations and variable climate conditions between the two regions which determine different iron-supply during burning of initial clay material. Results from the thermomagnetic analyses show that the dominant ferrimagnetic mineral in all burnt clay materials studied, is magnetite/titanomagnetite with low Ti content and different grain-sizes. High values of frequency-dependent magnetic susceptibility indicate the presence of significant amount of fine-grained (d<0·015 μm) superparamagnetic magnetite.     

Pottery firing temperatures: a new method for determining the firing temperature of ceramics and burnt clay

A new method for determining the maximum firing temperature of ceramics and burnt clay is presented. The technique relies on measuring the magnetic susceptibility on a step-wise re-fired sample. The validity of the method has been tested by determining firing temperatures of two sets of clay samples fired at temperatures ranging from 400 to 1000 °C. Aliquots of the same samples have been studied petrographically by optical microscopy on thin sections and analyzed by powder X-ray diffraction in order to monitor structural and mineralogical changes as a function of temperature. The method is demonstrated on samples from four geographically widely different sites and it is applied to a larger set of ceramics of Late (ca. AD 900–AD 1450) and Inca (ca. AD 1480–AD 1532) periods from the Northwestern Argentine region, dating to a limited period of time prior to the fall of the Inca Empire. The method is shown to be a powerful tool in revealing archaeological information about the change in firing technologies in the pre-Hispanic societies in the Andean area through time.     

Archaeometric study of medieval pottery excavated at Stari (Old) Ras,Serbia

A combined study of a series of polychromatic and monochromatic glazed medieval pottery shards excavated from the archaeological area of Stari (Old) Ras in southern Serbia, including petrographic and chemical analysis, powder X-ray diffraction (PXRD) and Fourier transform infrared (FTIR) spectroscopy, allowed us to clearly distinguish between two groups of ceramics. Ras pottery, made of fine-grained well-cleaned clay and characterised by a rich mineral assemblage, was produced by firing in a temperature range between 800 and 900 °C. Reljina Gradina ceramics were produced at similar temperatures from materials which, with regard to mineralogical and chemical composition, show clear similarity with local clay, suggesting that these samples are of local origin and production. This work is the first systematic archaeometric study of medieval pottery excavated on the territory of Serbia.     

Firing temperature of a clay core sample in a bronze tripod from Daxinzhuang Site in China using TL techniques

In this paper, we studied the thermal history of a clay core sample from one leg of a bronze tripod unearthed at Daxinzhuang Site, Shandong, China. The properties of the luminescence signals of quartz depend on the maximum temperature at which the quartz was annealed in the past. We examined the feasibility of measuring the thermoluminescence (TL) sensitivity change of quartz for exploring the firing temperature of archaeological materials. The sensitization factor of the 110°C TL peak (S₂/S₁) and the ratio of the 210°C TL peak to the 110°C TL peak at different annealing temperatures were utilized to unveil the firing temperature in the clay core sample. The firing temperature of the clay core sample was approximately 700°C–800°C, proving the clay core has been fired. This result proved that the clay core has been fired by human agencies and indicated on the temperature of the clay core in drying and firing given by the foundry workers before the actual casting step.     

Magnetic Sourcing of Obsidians in Southern South America: Some Successes and Doubts

Sourcing of archaeological obsidians is of great importance in unravelling the cultural, social and economic development of many ancient societies. Use of magnetic properties of obsidian fragments has been reported as a cheap, fast and versatile tool for these purposes. One hundred and seventy-six obsidians from archaeological sites and sources in Argentina and southern Chile were analysed magnetically using the weight-normalized intensity of JNRM (Intensity of Natural Remanent Magnetization), the intensity of JSIRM (Intensity of Saturation of Isothermal Remanent Magnetization) at 0·35 T and the bulk susceptibility. The method allowed identification of at least two different sources for archaeological materials found respectively to the north and south of the Lago Argentino, in SW Santa Cruz province, Argentina. Comparison of values from most samples in south and central Santa Cruz with those from a known source may lead to the interpretation that most of them belong to that source. In contrast, a critical analysis of the resolution of this using a larger than usual number of samples from three well distant obsidian sources in Argentina showed that two of the sources showed an almost complete overlapping of these three parameters, and all displayed a very large dispersion of values. This different result indicates that the magnetic sourcing of obsidians may not always have the resolution previously portrayed, but is applicable in certain localities.     

The Study of Attic Black Gloss Sherds using Synchrotron X-ray Diffraction

We have studied the mineral composition of the gloss and the ceramic body of three pieces of Attic Greek pottery by applying the technique of high-resolution powder diffraction using synchroton X-rays. The measurements were performed on Stations 2·3 and 9·1 at the Synchrotron Radiation Source, Daresbury Laboratory. High quality powder patterns from the bulk of the ceramics and from the gloss surfaces have been obtained. The diffraction results show interesting variations of mineral composition between the gloss of the different sherds as well as variations between the bulk and the gloss. This makes phase identification and comparison between different fabrics less ambiguous. Spinel minerals are present in the gloss which are absent in the main body of the ceramics. Diffraction lines from one surface match the patterns of hematite, magnetite/maghemite and hercynite, while solid solutions of spinel structures appear to be present in the gloss layer of another sample. Crystallite particle sizes and lattice parameters of the minerals in the gloss layer have been accurately determined. Supplementary scanning electron microscopy (SEM) reveals the gloss thickness to be approximately 20 μm but with variations down to 5 μm. Analysis of the diffraction profile for the hematite component reveals a particle size in the order of 0·027 μm.     

An attempt to estimate firing temperature using OSL pre-dose sensitization of quartz

The estimation of firing temperature of ceramics using methods based on pre-dose sensitization of the 110°C TL peak of quartz have yielded incoherent results. Recently the fast component of the CW-OSL of quartz has been observed to have pre-dose characteristics similar to that of the 110°C TL peak. The motivation for this study has been to look into the feasibility of this signal, the OSL counter part of pre-dosed TL emission, for the firing temperature identification. The variation in the sensitization ratio of the TL and OSL emissions with different heating temperatures was also utilized to unveil the firing temperature mark of the specimen.     

Infra-red Photoacoustic and Secondary Ion Mass Spectrometry Measurements of Obsidian Hydration Rims

A procedure has been developed for measuring obsidian hydration rim thicknesses on archaeological artefacts using infra-red photoacoustic spectroscopy (IR-PAS). Calibration of the IR-PAS values with depth was completed using secondary ion mass spectrometry (SIMS) and optical microscopy to relate the quantity of diffused water to the measured thickness of the hydration layer. By monitoring the absorbance intensity at 1630 cm⁻¹wavenumbers, hydration rims between approximately 1 μm and 12 μm may be accurately measured and used for chronometric age estimates. SIMS depth profiling has the ability to measure layers less than 1 μm thick, extending the age calibration to samples of less than 100 years in age.     

Immunoglobulin G in 1·6 Million-year-old Fossil Bones from Venta Micena (Granada,Spain)

We studied the presence of immunoglobulin G (IgG) in equid fossil bones from Venta Micena (Granada, Spain), dated at 1·6 Myr old, and from Atapuerca (Burgos, Spain) (0·12 Myr), and in ostensibly hominid fossils VM1960 and VM3691 (1·6 Myr) from Venta Micena and CV1 and CV2 (1·4 Myr) from Cueva Victoria (Murcia, Spain). Samples taken from the specimens were crushed to a fine powder and their mineral structure was dissolved in an ethylenediaminetetracetic acid (EDTA) solution. Fossil extracts were tested with antibodies against human IgG and against horse IgG with two independent immunological methods: dot-blotting (DB) and a modification of this latter method: quantitative dot-blotting (QDB). IgG was detected by DB and was quantifiable by QDB in some of the fossils tested. Equid fossils from Atapuerca and Venta Micena gave stronger reactions with the antibodies against horse IgG than with the antibodies against human IgG. Fossils VM3691 and VM1960 reacted more strongly with the antibodies against human IgG than with antibodies against horse IgG, whereas no IgG was detected in fossils CV1 and CV2. These findings show that species-specific IgG can be detected in fossils as old as 1·6 Myr. The immunological analysis of fossil proteins may help to solve palaeontological controversies.     

苏家村遗址烧土样品的过火温度研究

烧土制品作为最早的人工建筑材料,使人类的居住环境得到了根本性的改善。然而,学界关于烧土建筑的成因存在人为烘烤处理、缘自火焚、废弃习俗等多种观点。通过科技手段研究烧土制品的过火温度,有助于科学分析烧土建筑的成因,探讨与之相关的建筑工艺,丰富史前建筑史研究。磁学研究表明,考古遗址中的土壤及其他沉积物在受热后新生成了磁铁矿、磁赤铁矿等强磁性矿物导致磁性显著增强,且矿物成分和磁性几乎不会再发生变化;但当重烧的温度接近或大于原始烧成温度时,样品中原始矿物的破坏或新矿物的生成,会引起矿物磁性的改变。基于这一原理,实验室内分析受热黏土的磁化率随再加热温度的变化特征,可反映烧土制品的过火温度。苏家村遗址是大汶口文化晚期至龙山文化中期早段一处重要的聚落遗址,遗址中第5层为厚约20～40 cm的红烧土层且覆盖整个遗址,推测为房屋倒塌造成的建筑垃圾堆积层或人为堆积层,出土大量烧土块。本研究利用X射线衍射分析法、X射线荧光光谱分析法和磁化率法等对苏家村遗址出土的烧土样品开展了组成及构造特征和样品的过火温度的综合分析。结果表明,苏家村遗址烧土样品中的白灰层中人为地添加了白色陶土原料,土层中有意地添加了植物残骸作...     

A rock magnetic record of Pleistocene rainfall variations at the Palaeolithic site of Attirampakkam,Southeastern India

Attirampakkam, an open-air stratified Palaeolithic site in southeastern India is the focus of ongoing studies to investigate the nature of Lower and Middle Palaeolithic occupation in relation to changing Pleistocene environments. The paucity of faunal or palaeobotanical remains at the site required the use of rock magnetic properties (χ_lf, χ_fd, χ_fd %, χ_ARM, SIRM, χ_ARM/SIRM, SIRM/χ_lf, χ_ARM/χ_lf, χ_ARM/χ_fd, S-ratio, HIRM and HIRM/IRM_300mT) as proxies for deciphering the palaeoenvironments and palaeoclimates of the region. Rock magnetic data from stratified deposits within excavated trenches show that the bulk of the sedimentation was intermittent with no subaerial exposure of sediments for long periods, and points to fluctuating wetter and drier climates associated with the Acheulian to Late Middle Palaeolithic levels. There is a general trend towards a wetter climate from Layer 5 upwards. Layer 7 offers evidence of bacterial magnetite (χ_ARM/χ_lf > 40 and χ_ARM/χ_fd > 1000), suggesting the onset of micro-anaerobic environments as a result of floods. Greigite is indicated in Layer 5 (SIRM/χ_lf > 30 × 10³ A m^?1), which indicates a reducing environment. Layer 2 represents an arid climate (higher proportion of haematite and a coarser magnetic grain size). Layer 1a again is indicative of an arid climate (presence of calcrete, magnetically “hard” minerals and coarser magnetic grain size). Results indicate that the southeast coast of India experienced a mostly dry tropical climate during the Pleistocene. The detected occurrence of a few notably more arid intervals did not disrupt occupation of the site by successive groups of hominins.     

Storied landscapes makes us (Modern) Human: Landscape socialisation in the Palaeolithic and consequences for the archaeological record

The unusual nature of the Neanderthal archaeological record has attracted the attention of archaeologists for the past 150 years. On the one hand, the technical skill apparent in their lithic technology, the practice of symbolic cultural behaviours (such as burials), and their successful survival in harsh environmental conditions for more than 200,000 years demonstrate the adaptive success and underlying humanity of the Neanderthal populations. On the other hand, the apparent lack of abundant and repeated use of symbolic material culture has resulted in a number of researchers arguing that these populations were largely incapable of symbolism – a conclusion with significant implications for social organisation. This paper reviews ideas regarding the use of ‘place’ or ‘landscape’ by Neanderthals and argues that the identified differences between the archaeological records of Neanderthals and late Pleistocene Modern Humans is not so much the result of significant variance in cognitive capacities, but rather the use of contrasting approaches to interaction with the physical landscape. ‘Landscape socialisation’ is a Modern Human universal, but what if Neanderthals did not participate in this kind of landscape interaction? Would this difference in behaviour result in the apparently contradictory archaeological record which has been created? The ideas presented in this paper are drawn together as a hypothesis to be developed and tested.     

Methods for inferring paleohabitats from the functional morphology of bovid phalanges

The functional morphology of postcranial remains can be used to infer habitat preference. This approach is typically considered an “ecomorphological” method, and has frequently been applied to bovid postcranial remains. Methods for predicting habitat preference from bovid postcrania currently exist for femora, metapodials, and astragali. Here we describe three methods for predicting paleohabitats using measurements of African bovid phalanges (proximal, intermediate, and distal). The proximal phalanx method correctly predicted the habitat preference for 130 of 183 modern bovid specimens (71.0%, 2.8 times better than chance, p < 0.0001). The intermediate phalanx method correctly predicted the habitat preference for 115 of 163 modern bovid specimens (70.6%, 2.8 times better than chance, p < 0.0001). The distal phalanx method correctly predicted the habitat preference for 87 of 122 modern bovid specimens (71.3%, 2.8 times better than chance, p < 0.0001). These accuracies compare well with those of existing such methods (1.8–3.4 times better than chance). Analysis of the probabilities associated with the habitat predictions allows confidence thresholds to be established that identify specific predictions which have <5% chance of being in error. This raises the effective accuracy of the methods to 95%. Extensive exploration and manipulation of the underlying data demonstrate that the habitat predictions are generally robust, and are relatively independent of body weight, taxonomy, and sample composition. These methods are broadly applicable, relatively accurate, and can be used to generate independent predictions of habitat from different elements, and thus constitute a useful approach to inferring past environments.     

Reconstructing northern Chinese Neolithic subsistence practices by isotopic analysis

Stable isotope signatures of both human and non-human animal bone samples indicate that Neolithic farmers of the Yellow and Wei River basins in China potentially cultivated millet for two reasons: as a staple for human consumption and as fodder for domesticated animals, specifically pigs, dogs, and perhaps chicken. Bone samples were analyzed from four Neolithic sites: Jiangzhai, Shijia, Xipo, and Kangjia, spanning the time period from 7000 to 4000 years ago. A combination of very high carbon isotope ratios (δ¹³C = −7.7 ± 0.4‰) and low nitrogen isotope ratios (δ¹⁵N = 7.5 ± 0.5‰) in samples of Xipo pig and dog bone suggests that these monogastric animals consumed substantial quantities of C₄ plants, almost certainly millets. In fact, the proportion of C₄ plants in animal diets appears to have been even greater than that in human diet. Stable isotope values (δ¹³C = −10.0 ± 0.8‰; δ¹⁵N = 8.3 ± 0.5‰) of human bone collagen recovered at Jiangzhai and Shijia indicate a staple role for millets, as well as the consumption of both wild and other non-C₄ domesticated plant foods. As millet agriculture and animal husbandry apparently depended on one another, a strong mutualism between them was likely established in northern China during the Neolithic. We propose that variable redistribution of agricultural products between humans and animals, depending on the availability of wild resources and annual fluctuations in agricultural output, helped ensure the stability of Neolithic human subsistence in the Yellow and Wei River basins.     

Analyzing the process of domestication: Hagoshrim as a case study

Recent excavations at the Neolithic site of Hagoshrim, northern Israel, have yielded a large assemblage of skeletal fragments, representing mostly caprines, cattle and pigs. The three layers of the site's occupation span approximately 2000 years of a crucial period in the domestication of these taxa in the southern Levant, including Pre-Pottery Neolithic C (Layer 6, 7562 ± 85 BP and 7735 ± 55 BP) and the Pottery Neolithic cultures, Jericho IX (Layer 5, 6725 ± 120 BP) and Wadi Raba (Layer 4, 6505 ± 120 BP). Therefore, this site provides an outstanding opportunity to study the process of domestication in a comparative manner, both across taxa and through time. We used kill-off patterns, size reduction and changes in body proportions, and introduced statistical methods to discern the different stages of the domestication process for each taxon. Pig remains reflect simultaneous changes at the end of the 7th millennium BP: kill-off patterns, size and proportions of cranial and post-cranial elements all change between Layer 5 and 4 with no significant changes between Layer 6 and 5. Gradual changes—both between Layer 6 and 5 and between Layer 5 and 4—were found only for cattle, while caprine remains exhibit no changes throughout the site's occupation. These results can be explained in light of the differences between the taxa in terms of their life history strategies, among other things, that can be viewed as pre-adaptations to domestication.     

Methods for inferring paleohabitats from discrete traits of the bovid postcranial skeleton

Various “ecomorphological” methods exist for using the functional morphology of bovid postcranial remains to reconstruct paleohabitats. Most such methods use measurements, but both Gentry [The Bovidae (Mammalia) of the Fort Ternan fossil fauna, in: L.S.B. Leakey, R.J.G. Savage (Eds.), Fossil Vertebrates of Africa, vol. 2, Academic Press, London, 1970, pp. 243–323] and Köhler [Skeleton and Habitat of Recent and Fossil Ruminants, Münchner Geowissenschaftliche Abdhandlungen 25 (1993) 1–88] have identified numerous discrete (non-metric) traits of the bovid postcranial skeleton that are said to be indicative of habitat preference. However, these traits have not been systematically tested on a modern bovid sample. We report here such a test. Eighty-six non-metric characters were evaluated using a sample of modern African bovids (n = 197). Of the 86 characters, 48 were either insufficiently defined or exhibited too much intra-individual variation to be potentially indicative of habitat. Two characters were invariant in the sample. Of the remaining 36 characters, 11 were sufficiently correlated with habitat preference (Cramer's V > 0.5) to be of some potential use in reconstructing paleohabitats. These characters are primarily concentrated on the phalanges, and provide a means by which fragmentary phalanges can be used for habitat reconstruction, albeit at a broad level of resolution (open or closed habitat). The estimated accuracy of these methods is greater than 80%. Their use on fragmentary remains may lessen the bias introduced by basing habitat reconstructions on more complete fossils.     

Carbon isotope fractionation between diet,breath CO2, and bioapatite in different mammals

The carbon isotope fractionation between tooth enamel bioapatite, breath CO₂, and diet was measured for voles, rabbits, pigs, and cattle on controlled diets. The measured fractionation (expressed as isotope enrichment ɛ*) between enamel and diet was 11.5 ± 0.3‰, 12.8 ± 0.7‰, 13.3 ± 0.3‰, and 14.6 ± 0.3‰ for these respective species. There is a 1:1 correlation between ɛ*_{breath–diet} and ɛ*_{enamel–diet} (r² = 0.94, p < 0.01), whereas our data do not resolve significant inter-species differences in ɛ*_{enamel–breath}. These findings are consistent with the hypothesis that inter-species differences in ɛ*_{bioapatite–diet} are primarily a result of differences in digestive physiology, rather than differences in the magnitude of fractionation between mineral and body fluid.     

U-series Dating of Fossil Teeth and Carbonates from Snake Cave,Thailand

Snake Cave (Thailand) is an important site for the study of the evolution in Southeast Asia, leading to a discovery of rich and various faunas, including a human tooth. Fossils of large and small mammals converge to indicate, on the basis of faunal assemblage, a late Middle Pleistocene age for the fossiliferous layers; on the other hand, previous U-series dating of carbonates furnished a lower limit for the fossils of about 130 ky.In order to achieve a better comprehension of the chronology of the cave, the Uranium-series method for absolute age determination has been applied to some carbonates older than those studied previously and to fossils themselves.We used the isochron technique approach to yield valuable ages because spleleothem samples consist in a mixture of calcite and detrital contamination. The results obtained suggest that the main fossiliferous level is older than about 160 ky. The application of the U-series method to tooth samples from this tropical cave leads to erroneous ages, probably because of post depositional groundwater movements.     

Thermoluminescence dating

Over the last few years the Nordic Laboratory for Thermoluminescence (TL) Dating has obtained TL dates for a considerable number of archaeological samples, ceramics, bricks, burnt clay and burnt stones from the Nordic countries. The majority of TL dates have been consistent and in agreement with other dating evidence. Discrepancies caused primarily by excessive short‐term fading of the latent TL signal were encountered in a few cases. A procedure for eliminating errors caused by short‐term fading is described. A brief discussion of the sources of error in TL dating is given. Finally, results obtained by TL are compared with those obtained by radiocarbon for a number of sites.     

Assessment of material characteristics of ancient concretes,Grande Aula,Markets of Trajan,Rome

The Grande Aula, or Great Hall, of the Markets of Trajan (AD 96 to 115) is an intact example of the domed, concrete architecture of imperial Rome. Petrographic, x-ray diffraction, chemical, and SEM analyses demonstrate that wall mortars contain Pozzolane Rosse volcanic ash aggregate (harenae fossiciae) and strätlingite, a complex calcium aluminate cement hydrate (C₂ ASH₈) that gives modern cements good durability and compressive strength. Specific gravity tests and a new petrographic method for assessing bulk densities indicate unit weights of about 1750 kg/m³ for the wall mortars and 1430–1640 kg/m³ for the pumice bearing, vaulted ceiling mortars. Innovative point load source tests record the tensile strengths (f_t) of the aggregate and interfacial elements of the conglomeratic concrete fabric. These suggest f_t of about 2.7 MPa for brick, 1.2 MPa for Tufo Lionato tuff, and 0.9 MPa for Tufo Giallo della Via Tiberina tuff coarse aggregate (caementa), based on a tentative, approximate correlation with splitting (Brazilian) tests. The pozzolanic mortar and interfacial zones have lower f_t in the range of 0.8 MPa to 0.5 MPa. The relatively low mortar strength and its somewhat tenuous adhesion to the coarse aggregate suggests that the caementa may have arrested the propagation of tensile microcracks that formed in the mortar, thereby increasing the composite tensile strength of the concrete. Roman builders selected the complex aggregate mixes to optimize the performance of the wall and vault concretes.