Developing FTIR Microspectroscopy for the Analysis of Animal-Tissue Residues on Stone Tools

The analysis of microscopic residues on stone tools provides one of the most direct ways to reconstruct the functions of such artifacts. However, new methods are needed to strengthen residue identifications based upon visible-light microscopy. In this work, we establish that reflectance Fourier-transform infrared microspectroscopy (FTIRM) can be used to document IR spectra of animal-tissue residues on experimental stone tools. First, we present a set of reflectance FTIRM standards for the most commonly identified animal-tissue residues on stone tools: skin, meat, fat, hair, blood, feather barbules, fish scales, and bone. We provide spectral peak assignments for each residue and demonstrate that high-quality reflectance FTIRM spectra can be generated under ideal circumstances. Second, we document the spectra for these residues when they are located on a stone substrate such as flint or obsidian. We discuss procedures for correcting spectra that are affected by specular reflection and explain the effects of spectral interference from the stone. Our results show that reflectance FTIRM is sensitive to small intra-sample differences in composition. This means that it will record the effects of decomposition in ancient residues. The methodological developments we present here will help lithic residue analysts incorporate in situ reflectance FTIRM into their analysis protocols to strengthen identifications.     

Extracting residues from stone tools for optical analysis: towards an experiment-based protocol

The identification of residues is traditionally based on the distinctive morphologies of the residue fragments by means of light microscopy. Most residue fragments are amorphous, in the sense that they lack distinguishing shapes or easily visible structures under reflected light microscopy. Amorphous residues can only be identified by using transmitted light microscopy, which requires the extraction of residues from the tool’s surface. Residues are usually extracted with a pipette or an ultrasonic bath in combination with distilled water. However, a number of researchers avoid residue extraction because it is unclear whether current extraction techniques are representative for the use-related residue that adheres to a flaked stone tool. In this paper, we aim at resolving these methodological uncertainties by critically evaluating current extraction methodologies. Attention is focused on the variation in residue types, their causes of deposition and their adhesion and on the most successful technique for extracting a range of residue types from the stone tool surface. Based on an experimental reference sample in flint, we argue that a stepwise extraction protocol is most successful in providing representative residue extractions and in preventing damage, destruction or loss of residue.     

First results on thermally induced porosity in chlorite cooking vessels from Merv (Turkmenistan) and implications for the formation and preservation of archaeological lipid residues

Excavations at the ancient city of Merv in Turkmenistan have yielded a significant assemblage of ceramic and stone vessel fragments from contexts dating to the Sasanian and medieval periods (5th–13th centuries AD). Many of the vessel fragments are encrusted with apparent food residue deposits offering scope for organic residue analysis and the potential to compare the use of these two very different vessel types. To enable meaningful comparison we sought to establish whether the vessel stone (a talc-chlorite schist) can absorb and preserve organic residues indicative of past use. This paper reports the first investigation to address this question using standard methods for archaeological residue analysis coupled with study of the properties of the schist fabric and basic absorption experiments. The results demonstrate that heating during cooking, even at relatively low temperatures, modifies the stone microstructure by increasing its porosity. These pores enhance the absorption capacity of the schist fabric such that chlorite cooking pots can absorb and preserve sufficient organic residue to reflect the original processing of foodstuffs, as has been previously demonstrated for ceramic fabrics. Comparison of pore capacity, archaeological residue yield and experimental absorption indicates the significance of pore-size distribution for the relative retention and preservation of organic residues in these fabrics. The results of this study indicate that a wider range of archaeological material may be suitable for absorbed residue analysis than has previously been recognised. The findings also challenge previous assumptions concerning the relationship between the properties of chlorite vessels and their mode of use in Central Asia and Near East in antiquity.     

Swept under the rug: the problem of unacknowledged ambiguity in lithic residue identification

Microscopic analysis of organic residues on stone tools is used to interpret prehistoric stone tool functions. The morphology of some residues can be difficult to interpret, yet this ambiguity is rarely acknowledged in the literature. Our research seeks to understand the nature of this ambiguity by objectively identifying ambiguous residues in our reference collection. We trained four archaeologists in residue analysis using one part of our reference collection, then tested their ability to identify sixty-eight residues in another part of the same collection. Forty-eight of the residues in the test (70%) were correctly identified by three or all four subjects. We considered the remaining twenty residues, which were correctly identified by two or fewer of the subjects, to be ambiguous. These are most often in the hide-scraping, bone-scraping, and hardwood-scraping (macerated) categories, and tend to have an atypical morphology which falls in the range of variability of another residue category. Some of these residues also have optical properties which make them more difficult to image than others. We explore the potential for scanning electron microscopy (SEM) to improve residue identification in a second test. This test shows a modest improvement in identification success rates of ambiguous residues when SEM images are included. We conclude that while images from different types of microscopes can improve reliability of identification, some residues will always be ambiguous. Rather than being ignored, these ambiguities should be brought to light, closely examined, and published as such.     

DNA from ancient stone tools and bones excavated at Bugas-Holding,Wyoming

DNA residues may preserve on ancient stone tools used to process animals. We studied 24 stone tools recovered from the Bugas-Holding site in northwestern Wyoming. Nine tools that yielded DNA included five bifaces, two side scrapers, one end scraper, and one utilized flake. The excavators did not handle three of these tools with bare hands, and they were sealed in separate plastic bags to minimize contact with modern DNA. Five sediment samples did not yield mammalian DNA. One tool contained DNA from three species, and these templates competed during polymerase chain reaction (PCR) amplification. DNA identifications suggested a butchery pattern indicative of a human population under resource stress or a broader range of industrial activities at Bugas-Holding. We describe several improvements in DNA residue analysis, including a more effective DNA recovery protocol, methods to measure sensitivity and inhibition of PCR in each sample, and strategies to surmount competition between templates during PCR.     

Clues to Stone Tool Function Re-examined: Comparing Starch Grain Frequencies on Used and Unused Obsidian Artefacts

The identification of plant residues observed on prehistoric stone artefacts has often been used to inform on tool function without adequate consideration of potential contamination due to post-depositional processes. The paper redresses this balance by proposing a methodology which combines use-wear and residue analyses with systematic testing of depositional context to distinguish residues formed during tool use from accidental contamination. A case study involving obsidian artefacts from an open site in Papua New Guinea is used to illustrate the new approach. Starch grains, a class of residue which has had little attention outside Australia, were chosen as the focus of study because of their abundance at this site. The frequency of starch grains extracted from residues on stone artefacts was compared with those in sediments adhering to and adjacent to the artefact. A use-wear study conducted as a blind test provided an independent measure of whether the artefacts had been used. The frequency of starch grains was shown to be significantly correlated with used artefacts and not correlated with unused artefacts or the sediments. The case study demonstrates the importance of testing for contamination and also illustrates the benefit of studying starch grains as a class of plant residue.     

Assessing the reliability of pRIA for identifying ancient proteins from archaeological contexts

The use of immunological techniques for identifying the origin of proteins and inferring foodstuffs exploited by prehistoric occupations has been conducted for several decades. Cases of experimental laboratory and archaeological studies have shown the potential of these techniques for reliable results. However, very few of these case studies employ archaeological sites that have excellent preservation and high-resolution spatial contexts between identifiable faunal remains, features, and stone tools. We present an assessment of the identification reliability of one immunological technique, protein radioimmunoassay (pRIA), using faunal remains and stone tools from two sites from arctic and subarctic contexts. The results of this research indicate that, even in contexts with excellent preservation, the identifications produced by the pRIA technique are subject to misidentification and cross-reactions due to diagenetic alteration of proteins. We propose a higher minimum reaction value (percent binding of labeled antibody) that mitigates these effects, and renders the pRIA results more reliable for ancient, poorly preserved organic remains.     

Starch residues on museum artefacts: implications for determining tool use

A sample of 11 museum artefacts was examined to assess the preservation of any adhering organic residues, particularly starch granules, and to assess the potential for the identification of cooked starchy foods. The primary aim was to examine starchy deposits, extract starch granules and examine their physical condition to increase our understanding of the taphonomy of starch granules and associated organic residues in archived material and archaeological deposits. The study shows that organic plant residues could be recovered from archived artefacts and makes a significant contribution to understanding the function of this material. Recovered starch granules showed an interesting pattern of varying organic preservation on the surface of stone and wooden artefacts. Some starch granules were found to be well preserved while others in the same sample appeared to have been affected by enzyme degrading micro-organisms. Recovered residues included fully gelatinised starch.     

Hunter-gatherer tobacco smoking: earliest evidence from the Pacific Northwest Coast of North America

Chemical analysis of residue extracted from stone pipes and pipe fragments excavated at sites in the southern Pacific Northwest Coast of North America demonstrate that hunter-gatherers smoked the psychostimulant tobacco (Nicotiana sp.) by at least AD 860. Non-farming ethno-historic Native Americans throughout the west gathered and sometimes cultivated tobacco for ritual and religious purposes, but until now the antiquity of the practice on this part of the continent was unknown. Method validation includes chemical characterization of a suite of smoke plants and experimental reproduction of “smoked” pipe chemistry; results indicate biomarkers are traceable for several species commonly smoked by ethnographic native peoples, including tobacco (nicotine, cotinine), tree tobacco (anabasine), and kinnikinnick (arbutin). Developed methods—where residue is extracted directly from the stone or clay matrix of whole and fragmentary archaeological pipes—may be applied in similar studies investigating the spread and use of ritual smoke plants in the ancient Americas and elsewhere.     

Where were the hearths: an experimental investigation of the archaeological signature of prehistoric fire technology in the alluvial gravels of the Southern Plains

The interpretation that a rock has been subjected to cultural utilization is a basic element of hunter-gatherer research. The fracture mechanics of the flaked stone tool production process are well understood and the material residues are routinely identified during fieldwork. Conversely, non-percussion processes such as hot-rock technology, which can result in rock fracture, are less well understood. An experimental study has been developed to examine the fractured gravels observed at a prehistoric site on the Southern Plains (USA). The experiment has sought to determine whether cultural or natural agencies were responsible for the production of the angularly fractured rocks. The positive results of the experiment indicate that not only were humans most likely responsible for the breakages, but also that the fractured rocks often exhibit distinctive morphologies that may be identified during fieldwork. This simple experimental methodology is applicable to other hunter-gatherer sites where the depositional environment is not conducive to the structural preservation of features such as hearths.     

Chemical and Microscopic Study of Masonry Mortar in Ancient Pagodas in East China

Ancient mortars played a crucial role in the construction of historical architectures due to their physical and chemical compatibility with traditional building materials such as stones and bricks. Therefore, the analysis and optimization of the ancient mortar formula are significant in the restoration and preservation of historical sites. In this work, 20 mortar samples selected from five ancient stone pagodas in Zhejiang Province, China, were analyzed. The results showed that mud, lime-soil mortar, lime-sand mortar, and lime-gypsum mortar were used as binders in these pagodas. The Ca(OH)₂/aggregate ratio ranging from 0.3 to 2.7 was usually used to prepare lime mortar. Protein and polysaccharide were also found in some samples.     

Examination of prehistoric artifacts via fatty acid methyl ester (FAME) techniques using modern environmental stewardship

Elucidating the specific use and purpose of archaeological specimens such as stone axes and grinding stones can improve the understanding of an area's ecosystem and civilization. Chemical analysis of residues preserved on these tools may provide key information in identifying how the tool was implemented. The arid US Great Basin provides an ideal environment for the preservation of fatty acid residues.     

浙江旧石器考古综述

从2002年开始,浙江进行了一系列旧石器考古调查与发掘,成果表明古人类在浙江活动频繁、从早更新世晚段开始一直延续到晚更新世的某一阶段,持续时间很长。石制品的组合大多数归属于南方主工业,但也表现出了一些小流域的特色。从目前所发现旧石器地点分析,浙江旧石器考古研究的前景广阔。     

免疫学方法在科技考古学中的应用

通过免疫学的分析可以鉴定不同来源血液的种属。对古代器物表面的血液残留物进行种属鉴定,在石器用途研究、动物区系重建以及古人类食物来源分析等领域具有重要意义。介绍了免疫学在考古学中应用的基本理论及方法,对国外学者运用免疫学方法进行考古学研究的概况做了综述,对相关问题进行了探讨。     

The Role of Fire in the Life of an Adhesive

The use of fire is essential for the preparation of hafting adhesives; both are suggested to be a proxy for distinguishing the technological expertise and complex cognition among Palaeolithic populations. While use of fire has been argued to exist from about 1.0 Ma onwards, evidence for adhesives in the Palaeolithic record is rare and fragmented. In spite of the close link between fire places and adhesives, no study has ever focussed on examining the impact of heat on adhesive deposition and preservation. This paper discusses the results of a combustion experiment that was undertaken to understand the impact of heat exposure on hafting adhesives. The results have significant implications for archaeological interpretations. Deposition in or near a fire proves to severely impact the types of residues that preserve on a stone tool. The vertically transferred heat is responsible for the loss of adhesives but also for the incidental production of adhesives and their deposition on stone tools. It can be hypothesised that the rare survival of adhesives on archaeological stone tools might not only be the result of direct contact with the fire but also the result of degradation due to heat from overlying fireplaces. If we are to improve our understanding of the preservation of adhesives, it is important to unstand the taphonomic processes that affect these adhesives, in particular heat alteration.     

安徽何郢遗址植物残体切割形态与脱粒农具的关系

石器和植物残体的相关研究证明,脱粒板曾大规模应用于近东地区。为探索古代中国或远东是否也曾使用过这种工具或类似工具,本研究对何郢遗址植物残体形态进行了研究,结果表明中国商周遗址存在切割形态植物残体的证据,以此推测类似脱粒板的农具在商周时期曾被使用。无疑,这一发现对我国古代农作物的脱粒加工方式具有重要的启示,可望深化我国农业考古的探索。     

Study on the lithology of stone chimes (stone musical instruments in ancient China) and Lingbi stone

The oldest extant musical instruments in the world are stone chimes. This music was created by the ‘eight tones’ that could be produced by these ‘stone’ voices. Although many of these stone chimes have been unearthed from sites predating the Spring and Autumn Period and the Warring States Period in China, their discussion in archaeological reports is usually not very thorough. In this paper, the ancient and modern samples are analysed from the point of view of lithology. The aim is to explore how the ancients chose to make these stones, and to check that the type of stone from which these ancient Chinese stone chimes are made is actually those recorded in previous studies. The results show that most of the ancient stone chimes in China are made of limestone. These chimes required a material with a single, homogeneous and compact mineral composition. Lingbi chimes (a kind of ‘lithophone’ produced in Lingbi county, China, are pure in composition and have a fine microcrystalline structure, which is the best choice for making stone chimes. This paper makes a systematic study of the lithology of Chinese stone chimes. The results supplement a significant lacuna in the study of ‘lithophone’ and ancient stone instruments both in China and on a more global scale.     

Molecular evidence of bitumen in the Mousterian lithic assemblage of Hummal (Central Syria)

Evidence for bitumen use in Middle Palaeolithic sites is an exception in Pleistocene archaeology. This paper presents the discovery of three tar-bearing Levallois artefacts found in the Mousterian sequence in Hummal (Central Syria). The organic residues were submitted to geochemical study. Gas chromatography–mass spectrometry analyses of saturated and aromatic hydrocarbons and isotopic data show the presence of bitumen. The most likely location of natural asphalt provisioning is the Shaaf outcrop in the Bichri desert. The bitumen-bearing stone tools add further important data to the growing knowledge about bitumen processing in the Middle Palaeolithic spring sites of El Kowm. Identification of the provisioning place for natural asphalt enables a more precise assumption about the site's catchment area. From a technological point of view, the tar-bearing specimens provide information on the range of tool forms selected for hafting. Ballistic features arguably indicate that the pointed Levallois blanks seem to be spear points that were fitted to a wooden handle. In at least one case, this technical procedure was seemingly executed during a brief episode of occupation and replacement of worn out implements. This small, bracketed window of detailed insight into Mousterian technology is linked with the more general relationship between Levallois technology and stone tool hafting.     

Experiments with Lithic Tools: Understanding Starch Residues from Crop Harvesting

Stone knives were used widely in Neolithic East Asia, presumably in the harvesting of grain crops, but their function has not been clearly understood due to the lack of study of residues from these tools. To address this issue, starch grain analysis was employed to study the residues on the surface of ancient stone knives and large amounts of starches were recovered. The sources of these starches, however, were not well understood, because harvesting of crops involves the cutting of stems rather than direct contact with starchy seeds. To determine whether harvesting could deposit these types of residues, we designed a simulation experiment using stone flakes to harvest ears of wheat, rice and foxtail millet, then analysed the residues on both the flakes and in the plant tissues. A large number of starch grains were found in the stems, including both typical morphotypes from seeds and newly described types that occur only in stems, which can be used as indicators of harvesting. Our study demonstrates that starch grains from residues on the surfaces of archaeological stone knives can indicate not only that the tools were used to harvest ears, but also the type of crops harvested.     

岩石材料工程性能的研究——石质文物保护科技的基础性研究方向

从既有岩石材料构筑物的研究、保护和利用出发,提出了岩石材料工程性能研究是石质文物保护科技保护的基础性研究方向,在总结了岩石力学、地球化学、地球物理学、环境地质学、矿物学五个相关领域的研究现状后指出目前存在的三大基础性问题。在此基础上提出了岩石材料工程性能研究的基本框架和首要问题,并对首要问题内的基本研究内容进行了较为详细的论述。