Statistical tool for dating and interpreting archaeological contexts using pottery

Analyzing chronological patterns is one of the major issues in archaeology. How can the date of a specific context be estimated? Is it possible to identify residual and intrusive material in it at the same time? Numerous statistical methodological approaches have been developed and implemented to estimate dates but have less often addressed the issue of socio-economic area or the functional interpretation of contexts. This article deals with the construction and analysis of two different probability estimate density curves of context dates using pottery. By contrasting the two curves we can define the boundaries of the socio-economic area and make a chrono-functional interpretation of a context. This statistical tool allows the archaeologist to visualize and analyze chronological patterns easily. The method is applied to the analysis of contexts in the town of Tours in particular and more generally in the centre-west of France, based on collected pottery finds.     

A re-assessment of Basketmaker II cave 7: massacre site or cemetery context

Our ongoing investigation of early maize farming in the American Southwest has entailed stable isotope analysis and accelerator radiocarbon dating of Basketmaker II remains from sites in the Four Corners region. Here we report radiocarbon dates on a large mortuary assemblage excavated by Richard Wetherill in 1893 from a burial cave in southeastern Utah. It has long been thought that all individuals interred in Cave 7 were massacred in a single violent attack given embedded projectiles and evidence for blunt force trauma. However, accelerator radiocarbon dates on purified bone collagen (n = 96) do not lend strong support to this argument, even among the subset of individuals with clear evidence for violent injuries. Moreover, nearly 80% of Cave 7 burials examined in the study show no evidence of perimortem trauma and no adult females or subadults under the age of 12 appear to have suffered violent deaths. Rather than an anomalous single-event massacre, the Cave 7 radiocarbon dataset suggests that raiding and intra-group, male/male violence was episodic among Basketmaker groups in southeastern Utah. Population densities were relatively high and individuals interred in Cave 7 and elsewhere in the region were heavily dependent on maize agriculture, a prehistoric economic strategy typically characterized by high amplitude fluctuations in productivity. Variability in the array of grave goods accompanying Cave 7 male burials and elsewhere suggests competitive social differentiation likely heightened during periods of resource shortfall leading to intra-group conflict, raiding and perhaps ritualized acts of violence.     

Chronologies in wood and resin: AMS C dating of pre-Hispanic Caribbean wood sculpture

This paper establishes a chronological framework for selected pieces of Caribbean (Taíno/Lucayan) wooden sculpture, enabling previously ahistoric artefacts to fit back into the wider corpus of pre-colonial material culture. Seventy-two ¹⁴C AMS determinations from 56 artefacts held in museum collections are reported, including 32 ceremonial duhos, or seats. Far from being constrained to the last few centuries prior to contact, the dates for these objects extend back to ca. AD 250, and include the artistic legacies of various cultures. Duhos in both low and high back styles are present from about AD 600, if not earlier, in a distribution that spans the Antillean island chain from Trinidad to Cuba. Complex, drug-related paraphernalia and elaborate ancestral reliquaries are in evidence by AD 1000, as are some distinctive regional styles – such as the unique iconography from the Bahamas and Turks and Caicos islands. This paper explores relevant methodological issues – from the challenges of working with museum pieces (e.g., uncertain provenance, discrete sampling techniques, impact of previous conservation treatments on dating results), to dealing with potential ‘in-built’ age in tropical hardwoods.     

Croatian Appoxiomenos alloy composition and lead provenance study

An ancient bronze statue of an athlete with a strigil (known as Apoxiomenos) – was raised from the north Adriatic Sea in 1999. In order to help to determine its place and date of manufacture various scientific techniques were used. ¹⁴C dating performed by the Accelerator Mass Spectrometry (AMS) on the organic material found inside the statue gave calibrated dates between 100 B.C. and 250 A.D. Non-destructive analysis performed by portable X-Ray Fluorescence (XRF) system and external beam Particle Induced X-Ray Emission (PIXE) spectroscopy could not provide representative results for metal alloy composition due to the electrochemical deterioration of the surface of bronze in seawater. This was observed by the analysis of alloy cross-sections performed by the proton microprobe. The analysis showed much higher lead concentrations on the surface of the bronze than inside, confirming that realistic alloy composition can be only performed on samples taken from at least 0.6 mm below the surface. Subsequent micro-PIXE analysis on metal cross-section showed inhomogeneous lead concentrations between 1 and 12%. Lead isotope analysis for provenance investigation has been done on 15 samples using Multi Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). Analysis showed that lead isotope composition is consistent with some of the lead ores originating either from the Eastern Alps or from Sardinia. Altogether, the results lead to the conclusion that the statue is not of a Greek origin, but most probable it is a Roman copy of the Greek original.     

Dating Danish textiles and skins from bog finds by means of C AMS

This study presents the results of 44 new ¹⁴C analyses of Danish Early Iron Age textiles and skins. Of 52 Danish bog finds containing skin and textile items, 30 are associated with bog bodies. Until now, only 18 of these have been dated. In this paper we add dates to the remaining finds. The results demonstrate that the Danish custom of depositing clothed bodies in a bog is centred to the centuries immediately before and at the beginning of the Common Era. Most of these bodies are carefully placed in the bog – wrapped or dressed in various textile and/or skin garments. The care with which these people were placed in the bog indicates that they represent a hitherto unrecognised burial custom supplementing the more common burial pratice for this period.     

New age constraints for hominid footprints found on Jeju Island,South Korea

In 2004 numerous hominid footprints, along with diverse animal footprints, were found in the Late Quaternary strata of Jeju Island, South Korea. However, the age of the sediments in which the footprints were found is still controversial. Previous age estimates included radiocarbon ages of ca. 15,000 yr BP (Late Pleistocene) and quartz optically stimulated luminescence ages of ca. 7000 yr BP (mid-Holocene). In this study we report on 11 AMS ¹⁴C dating results from a new set of samples collected from the footprint-bearing strata and from associated sediments. Despite some variations and age reversal, all samples collected from the footprint-bearing strata yielded ¹⁴C ages of late Pleistocene. These ages are comparable with previous radiocarbon dating results. Furthermore, the presence of the proboscidean footprints attributable to woolly mammoths in the footprint-bearing strata supports the radiocarbon dating results. Based on the new radiocarbon dates and the presence of the alleged mammoth footprints, the age of the hominid footprints found at Jeju Island is thought to be late Pleistocene (about 19,000–25,000 cal yr BP). Therefore, this is the second discovery of hominid footprints dated to the Pleistocene age in Asia, and the first to be discovered in Korea.     

瓷器热释光断代中β平均剂量计算方法研究

瓷器热释光测定年代的样品一般都是用厚度为 0 .2 0 .5mm的瓷片 ,这样厚度的瓷片 ,用实验室 β源进行辐照时 ,由于瓷对 β剂量的积累和衰减作用 ,已不能将它作为一个均匀受照体 ,所以瓷器的 β吸收剂量只能用平均剂量来表示。本工作用铝代替瓷 ,用实验和理论计算的方法 ,得到了 β辐照吸收剂量在瓷器中随深度变化的函数 ,根据这个函数 ,可以方便地计算出任何厚度瓷片的 β平均吸收剂量。     

瓷器热释光高温峰测年的初步研究

对陕西耀州窑4个古瓷器碎片的热释光高温峰测量的结果表明,瓷器样品具有天然热释光信号,而且,其信号增长呈良好的线性,高温峰可以用于瓷器的年龄测定和真假鉴定之中,瓷器热释光高温峰技术有望成为热释光测定瓷器年龄的一个方法。     

Radiocarbon Dates from the Oxford AMS System: Archaeometry Datelist 36

This is the thirty‐sixth list of AMS radiocarbon determinations measured at the Oxford Radiocarbon Accelerator Unit (ORAU). Amongst some of the sites included here are the latest series of determinations from the key sites of El Mirón (Spain) and Sutton Courtney (UK), as well as others dating to the Palaeolithic, Mesolithic and later periods. Submitters of the material provide comments on the significance of the results.     

古陶瓷热释光测定年代发展

对古陶器热释光测定年代的两个标准方法——“细粒混合矿物技术”和“粗粒石英技术”作了详细的论述,介绍了这两个方法中古剂量和年剂量测量方法的发展和现状,对影响古剂量和年剂量测量准确性的一些复杂因素和解决的方法进行了分析,着重叙述了古瓷器热释光测定年代的新发展——“前剂量饱和指数法”。几十年的研究结果表明,热释光测定年代在古陶瓷真伪鉴定上已经取得了很大的成功,但是在年代测定的精确度和准确度上还不够,需要深入研究。