Tracing firing technology through clay properties in Cuzco,Peru

The purpose of this study was to identify changes in firing practices that occurred during a timeframe that saw the introduction of European kiln technology to the Andes (AD 900–1800). Pottery from an excavated context at the archaeological site of Aqnapampa in the southern highlands of Peru was examined for changes in paste recipes that adapted local materials to increased firing temperatures indicative of evolving firing technologies. Sherds (60) and fragments refired to 890 °C from 12 stratigraphic levels were compared by style, surface treatment, paste color, and vitrification structures (ESEM). Four technological phases of the Cuzco pottery sequence emerged and were used to evaluate the trajectory of a single decorative style (Killke). Previously thought to have been produced in pre-Inca times and curated into later periods, the Killke sherds presented evidence that the style was produced using technologies introduced in the Inca and Spanish Colonial Period.     

FOCUS: Provenance of Ceramics Revealed by Magnetic Susceptibility and Thermoluminescence

A new method for provenance determination of ceramics is presented. The samples were measured for magnetic susceptibility and for the TL intensity produced by artificially induced radiation in a pre-heated sample. Characteristic differences in magnetic susceptibility and TL sensitivity were found to exist between different clay sources, and in a diagram of susceptibility versus TL intensity, ceramics of different provenances often plot in distinctly different areas. Samples of 0·01–1 g of burnt clay were used. The method has been tested on a dozen archaeological sites, three of which are presented here as examples. Choice of tempering material, firing temperature, and oxygen tension during firing affect the susceptibility and the TL signals somewhat, and these effects have been tested experimentally.     

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.     

A Bayesian AMS C chronology of the Classic Maya Center of Uxbenká, Belize

Archaeologists require precise chronologies of cultural change to understand the nature and timing, and causes and effects, of ecological and social transformations. The Uxbenká Archaeological Project (UAP) has made chronology building a main goal, employing epigraphic data, artifact seriation, and high-precision AMS ¹⁴C dating. With more than 60 ¹⁴C dates with measurement errors below ±25 ¹⁴C yr, primarily on single charcoal specimens, Uxbenká may be the most intensively dated Classic Period site in the tropical Maya Lowlands. Here we take the next step, combining this rich chronometric dataset with associated stratigraphic information in OxCal's Bayesian framework to generate a high-resolution chronology of Uxbenká's early development and expansion in southern Belize. We show how archaeologists may take advantage of complex architectural stratigraphy to constrain broad calibrated ranges during the Classic Period, and to estimate dates for observed construction events that can not be directly dated (e.g., clearing/leveling plazas, laying plaster floors, renovating/rebuilding structural elements). Our analysis confirms the antiquity of the ceremonial Stela Plaza (Group A), where first construction is estimated between 60 cal BC and cal AD 220 and is associated with a Pre-Classic structure obscured by later construction and reorientation of the group to a N-S alignment ca. AD 150–310. The analysis also indicates initial leveling and construction at plaza Group B from cal AD 60–310 and Group D from cal AD 20–240, both earlier than previously assumed. Though Late Classic contexts are not as well represented by direct dates, architectural modifications are documented at all three plaza groups after AD 550, including the extensive plastering, laying paving stones, and construction of facades on existing structures. The resulting chronology revises our previous thinking on the mode of settlement and development of Classic Maya society at Uxbenká and indicates specific areas of investigation to elucidate events in the Late and Terminal Classic at the site, including political and social fragmentation and the abandonment of the urban core late in the Classic Period.     

The technological development of stonepaste ceramics from the Islamic Middle East

The microstructures and chemical compositions of stonepaste bodies from the Islamic Middle East, typically produced from a mixture of ten parts crushed quartz, one part crushed glass and one part white clay, are investigated using analytical scanning electron microscopy. For comparison, replicate stonepaste bodies are produced in the laboratory at firing temperatures in the range 900–1200 °C, and are similarly examined. The stonepaste bodies are divided into four primary microstructural groups that reflect the increasing reaction during firing of the glass fragments with the clay and quartz particles. The observed microstructures are then used to assess the geographical and chronological variations in the production technology of stonepaste ceramics from Egypt, Syria, Iran, Uzbekistan and Turkey, spanning the period from 11th to 17th centuries AD.     

Strength,Toughness and Thermal Shock Resistance of Ancient Ceramics,and Their Influence On Technological Choice

The basic underlying theory for the strength, toughness and thermal shock resistance of brittle multiphase clay ceramics, together with the measurement procedures to determine these parameters, are first outlined. Published experimental data obtained for test bars containing different types of temper and fired to a range of temperatures are then compared both with theoretical predictions and between themselves. The results confirm that to produce pottery with high strength requires high firing temperatures and low temper concentrations. Conversely, to produce pottery with high toughness and thermal shock resistance requires low firing temperatures and high temper concentrations, with platy or fibrous temper being most effective. There is no convincing published evidence that strength and toughness requirements were a significant factor in determining the technological choices (clay type, temper type and concentration, and firing temperature) in the production of pottery used as containers for transport and storage. In contrast, the routine use of high temper concentrations and low firing temperatures in the production of cooking pots suggests that the requirement for high thermal shock resistance was a factor that at least influenced technological choice in this case. In addition, there is some evidence that limestone and shell were, on occasions, deliberately chosen as temper in cooking pots. The need to take into account the crucial role that the full range of environmental, technological, economic, social, political and ideological factors have in influencing technological choice is also emphasized. This review highlights the fact that our current understanding of the factors determining strength, toughness and thermal shock resistance of clay ceramics is still far from complete. Further systematic measurements of these parameters, together with the establishment of a systematic database of the range of technological choices associated with the production of cooking pots, are therefore to be encouraged.     

Determining the Firing Temperature of Low‐Fired Ancient Pottery: An Example from the Donghulin Site,Beijing, China

The traditional thermal expansion method using a dilatometer fails to accurately determine the original firing temperatures of low‐fired ancient pottery. For this reason, we have developed an improved method of determining firing temperatures for low‐fired pottery. This paper explains the theory of the improved method and presents the reasonably satisfactory results obtained on ancient pottery from the Donghulin site (c. 10 000 bp ). The method and the results are very important for the study of ancient pottery culture and clay moulds used for bronze casting.     

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...     

Taken with a Grain of Salt: Experimentation and the Chemistry of Archaeological Ceramics from Xaltocan,Mexico

Neutron activation analysis (NAA) of ceramics from Xaltocan (n?=?651) displays high values for sodium and potassium and low concentrations of many transition metals and rare earth elements compared to other sites in the Basin of Mexico. Given that Xaltocan was situated on an island in the middle of a saline lake, the potential reasons for this chemical signature are diverse. On one hand, if the sodium and potassium were elevated due to some behavioral aspect of the potters, the Xaltocan chemical groups provide a glimpse at the behaviors of Xaltocan potters that permit more precise source designations. On the other hand, if this chemical fingerprint arose due to contamination in a saline post-depositional environment, the Xaltocan chemical groups would not be valid references for provenance studies. To evaluate these alternative hypotheses, we employ several lines of evidence: (1) comparison of the Xaltocan ceramics to over 5,000 NAA assays of clays and ceramics from the Basin of Mexico, (2) experimental doping of clays with water of different salinities and fired to different temperatures, (3) leaching experiments of archaeological pottery sherds (n?=?22) recovered from the site of Xaltocan, and (4) laser ablation–inductively coupled plasma–mass spectrometry of the clay and temper fraction of a small sample of Xaltocan ceramics to determine which component is responsible for the elevated sodium and potassium values. The results suggest that the high sodium and potassium values were present in the ceramic paste before firing. We then use these newly established reference groups to better understand the role of Xaltocan in the regional economy. The type of experimentation employed in this study has proven to be an important method for determining the behaviors of ancient potters and distinguishing them from post-depositional processes.     

Palynological study of a Mi'kmaw shell midden,Northeast Nova Scotia,Canada

Before now, no palynological studies were made on shell midden deposits in Nova Scotia, despite a long history of archaeological research. A test study of samples taken from the shell midden at Maligomish (Indian Island) on the Northumberland Strait was conducted to determine if sufficient pollen, fern and moss spores, and other non-pollen palynomorphs (NPP's, including fungal remains, algal spores) could be recovered to allow interpretation of environmental conditions at the time of deposition. Several pollen processing methods were tested: sieving and swirling, chemical treatment with cold HCl, 5% KOH and brief exposure to 5% NH₄OH, and treatment with acetolysis solution. We recovered variable amounts of pollen, spores and NPP's from samples taken at 3–5 cm, 5–15 cm and 15–25 cm below surface. Abundant microcharcoal fragments prevented effective use of the swirling technique, but sufficient palynomorphs were recovered by chemical treatments to allow assessment of down-section changes in assemblages. Three radiocarbon ages from Mya arenaria and Crassostrea sp., and measurements of sediment grain size, moisture, organic and inorganic carbon, provide a framework for analysing palynological assemblage changes and context for interpreting differential palynomorph preservation. Despite some oxidation and microbial degradation of palynomorphs in the time interval (ca. 380–1600 cal yr BP), the midden assemblages correlate with pollen zones from marine and lake core sites within ca. 50 km of Maligomish. Shifts in abundances of algal spores, testate amoebae and aquatic plant pollen also indicate changes in depositional conditions during the time of midden use. The study provides the first reference for archaeologists attempting to use palynology for analysis of samples from Nova Scotian shell-bearing contexts.     

Holocene land-use evolution and associated soil erosion in the French Prealps inferred from Lake Paladru sediments and archaeological evidences

A source-to-sink multi-proxy approach has been performed within Lake Paladru (492 m a.s.l., French Prealps) catchment and a 6-m long sediment sequence retrieved from the central lacustrine basin. The combination of minerogenic signal, specific organic markers of autochthonous and allochthonous supply and archaeological data allows the reconstruction of a continuous record of past human disturbances. Over the last 10,000 years, the lacustrine sedimentation was dominated by autochthonous carbonates and the watershed was mostly forest-covered. However, seven phases of higher accumulation rate, soil erosion, algal productivity and landscape disturbances have been identified and dated from 8400 to 7900, 6000 to 4800, 4500 to 3200, 2700 to 2050 cal BP as well as AD 350–850, AD 1250–1850 and after AD 1970. Before 5200 cal BP, soil erosion is interpreted as resulting from climatic deterioration phases towards cooler and wetter conditions. During the Mid-Late Holocene period, erosion fluxes and landscape disturbances are always associated with prehistorical and historical human activities and amplified by climatic oscillations. Such changes in human land-used led to increasing minerogenic supply and nutrients loading that affected lacustrine trophic levels, especially during the last 1600 years. In addition, organic and molecular markers document previously unknown human settlements around Lake Paladru during the Bronze and the Iron Ages.     

ON THE USE OF COLOUR COORDINATES TO EVALUATE FIRING TEMPERATURES OF ANCIENT POTTERY*

Colour measurement was investigated as a means to evaluate equivalent firing temperatures of ancient pottery. Colour coordinates were determined on samples of six clays previously fired, and then refired, in the temperature range 600–1100°C. Under the adopted conditions, significant variations of colour hue and saturation were normally observed on refired samples only after the original firing temperature had been exceeded; less reliable information was provided by luminosity. Original firing temperatures of clay samples were correctly recognized in most cases by projecting the points representing samples’ colour on to the a*b* plane of the ClEL*a*b* colour space.     

Living and dying as subjects of the Inca Empire: Adult diet and health at Puruchuco-Huaquerones,Peru

Imperial strategies varied as the Inca expanded their empire from the capital in Cusco. Some communities were conquered violently while others were ruled indirectly with little evidence of Inca presence. According to ethnohistorical evidence, the central coast was peacefully annexed by the Incas ca. A.D. 1470, but little is known about how Inca imperialism may have affected the quality of life of subjects of the Inca Empire. We integrate multiple lines of evidence to assess diet, health and disease for a sample of human remains from the Late Horizon cemetery of Puruchuco-Huaquerones, Peru. Specifically, we examine and analyze osteological, dental and stable isotope data (n = 162, 90 and 46 respectively) in order to investigate whether the Inca period population at Puruchuco-Huaquerones experienced nutritionally insufficient diets and poor health under imperial policies. Diet at Puruchuco-Huaquerones incorporated a variety of foods, both plant and animal. Osteological lesions and stature indicate periods of stress, with males experiencing more illness relative to females. Stature sexual dimorphism, the presence of healed lesions and isotope data indicate a sufficiently nutritious diet and support the conclusion that, although disease was present, individuals were healthy enough to survive and recover. Geographical and temporal comparisons suggest that health changed little with the Inca annexation of this region, but future work is needed.     

A prehispanic Maya pit oven? Microanalysis of fired clay balls from the Puuc region,Yucatán,Mexico

Excavations of a kitchen at Escalera al Cielo in the Puuc Maya region of Yucatán, Mexico uncovered a concentration of fired clay balls (ca. 3–5 cm in diameter), in addition to other de facto domestic refuse. The kitchen pertains to an intensively excavated elite residential group that was rapidly abandoned sometime near the end of the Terminal Classic period (A.D. 800–950), resulting in floor assemblages that provide an opportunity to explore the types and distribution of daily household activities. The results of experimental replications and a suite of analyses comprising modal analysis, ceramic petrography, Fourier transform infrared spectroscopy (FTIR), and microbotanical residue analysis reveal aspects of clay preparation, firing temperatures, repeated use of the balls, firing conditions, and specific plant food or fuel residues adhering to them. We show that the fired clay balls were manufactured with local, clay-rich soil and employed by the inhabitants of Escalera al Cielo as heating elements; relatively high concentrations of microbotanical residues from edible plants adhering to them support the hypothesis that they were involved in kitchen activities related to food processing.     

Using hearths for temper: petrographic analysis of Middle Woodland charcoal-tempered pottery in Northeast Florida

Charcoal-tempered pottery is uncommon in North America, but was produced with notable frequency in Northeast Florida from ca. AD 300–600. Thirty-six thin sections of pottery were analyzed by petrographic analysis and compared to 10 clay samples in order to characterize the paste of charcoal-tempered wares in terms of charcoal and mineralogical composition and abundance, assess the number of clay sources used to make the pottery, identify the species of wood represented in charcoal inclusions, and infer techniques of ceramic production. This analysis identified four temper categories, three texture groups, and three distinct clay resources used to make charcoal-tempered pottery, all of which were likely local to Northeast Florida. Identified wood taxa include pine (Pinus sp.), cedar (cf. Juniperus sp.), cypress (cf. Taxodium sp.), and sassafras (Sassafras albidum), with pine suspected to be the most common. These genera of charred wood, which exhibit minimal shrinkage in the samples, along with the prevalence of bone and grog inclusions, indicate that hearth contents were processed as temper, sometimes in combination with quartz sand. Potential reasons for the use of hearth contents as temper are considered.     

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.     

An Etruscan ointment from Chiusi (Tuscany,Italy): its chemical characterization

This paper focuses on the chemical characterization of the original contents of an Egyptian origin alabaster unguentarium, found in an Etruscan burial in Chiusi (Tuscany, Italy) and dated 150/125–100 B.C. The unguentarium, found in an intact tomb belonging to a noble woman of Chiusine society, preserved a good part of its original contents owing to a protective layer of clay. The chemical characterization was carried out using a combination of two analytical procedures based, respectively, on Fourier transform infrared spectroscopy (FTIR) and gas chromatography–mass spectrometry (GC–MS).     

Temper mixture models and assessing ceramic complexity in the emerging Tarascan state

This study presents compositional data from ceramics drawn from surface survey and controlled excavations from three prehispanic sites within the relatively small Lake Pátzcuaro Basin, representing a ceramic sequence stretching nearly 1500 years, from the Preclassic to Late Postclassic Tarascan state (ca. 50 B.C.–1525 A.D.). Using neutron activation analysis, we identify compositional groups and model the importance of volcanic materials as temper in the construction of prehispanic ceramics by matching mathematical simulations of clay–ash mixes to the compositional groups. Rather than discreet clay resources and spatially circumscribed production, we argue for a broadly dispersed and highly varied organization of pre-Tarascan and Tarascan state ceramic production in which the potters' distribution and use of specific volcanic ashy additives, not clays, structured the organization of production.     

Combined archaeomagnetic and thermoluminescence study of a brick kiln excavated at Fontanetto Po (Vercelli,Northern Italy)

A combined archaeomagnetic and thermoluminescence study was carried out as part of a rescue archaeological excavation on a kiln discovered during the installation of methane gas pipelines beneath a rice field, along the southern border of Fontanetto Po village (Vercelli province, Italy). A total of 23 independent brick samples have been collected, oriented in situ with an inclinometer; the use of magnetic and sun compass was not possible due to the existence of metallic tubes beneath the kiln and a plastic cover above it. Standard archaeomagnetic procedures have been used for the determination of the archaeomagnetic inclination and absolute geomagnetic intensity. Stepwise thermal demagnetization shows a very stable characteristic remanent magnetization and the calculated mean inclination of the 23 samples is I = 65.3° with α₉₅ = 2.4° and k = 156. Archaeointensity experiments have been performed using the classical Thellier method as modified by Coe, with regular partial thermoremanent magnetization (pTRM) checks. The cooling rate and remanence anisotropy effects upon thermoremanent magnetization (TRM) have been investigated in all the specimens. A total of 19 archaeointensity determinations (at specimen level) that correspond to linear NRM–TRM plots were used for the calculation of the site mean archaeointensity that is 46.4 ± 2.9 μT. Archaeomagnetic dating results show two possible dating intervals for the last 1000 years, calculated at 95% confidence interval: a first one from 1511 to 1614 AD, and a second one from 1768 to 1872 AD. Thermoluminescence (TL) study has been also performed on two brick samples from the kiln's internal wall, using conventional laboratory procedures. According to the thermoluminescence results the kiln's last usage lies between 1796 and 1914 AD. This age is in good agreement with the second dating interval obtained by the archaeomagnetic analysis. The combined archaeomagnetic and thermoluminescence results suggest that the last firing of the kiln could have occurred between the end of the 18th century and the beginning of 20th century.     

Insights into immigration and social class at Machu Picchu,Peru based on oxygen,strontium, and lead isotopic analysis

The Inca Empire (AD 1438–1532) made common practice of relocating individuals, households and entire communities throughout their expansive realm for different reasons depending on subjects' assigned social class. Reconstructing patterns of immigration at Inca-period sites could therefore permit some estimation of the social class(es) among their constituents, and thereby provide insights into the functional dynamics of Inca political economy. However, this is a difficult endeavor using only archaeological lines of evidence. This study presents oxygen, strontium and lead isotopic results from the well-preserved, well-contextualized skeletal population (N = 74) from the Inca site of Machu Picchu, Peru. Isotopic data are used to reconstruct patterns of immigration at the site, which are in turn used to directly estimate the social class of the population. The resulting isotopic data are widely distributed with no apparent modality, matching the expected distribution of a particular class of nonelite retainers. A novel application of multivariate statistics coupled with geological and faunal isotopic reference data also permits tentative estimation of individuals' regions of origin. This study provides empirical and analytical frameworks for future research in reconstructing residential movement and class dynamics in the late prehistoric Andes.