The application of Mössbauer spectroscopy to the characterisation of western mediterranean obsidian

Iron-57 Mössbauer absorption spectra have been measured for samples of obsidian from known geological flows and from archaeological site material from the western Mediterranean region. Of the four main sources available to prehistoric man it is possible to distinguish Sardinian (SA) and Pantellerian obsidian from Lipari obsidian on the basis of differences in the local atomic surroundings of iron atoms, as determined from the Mössbauer spectra. There is, however, some overlap between Lipari and Pontine Island obsidians. The Gabellotto flow on Lipari is readily identified through the presence of magnetite inclusions. The ratio of ferric to ferrous ions is found to be much higher in the surface layers (< 60 μm) than in the bulk obsidian as detected using Mössbauer backscattering.     

古代文物表面常见天然有机物的显微共聚焦拉曼光谱研究

为了鉴别文物表面常见的天然有机物,采用显微共聚焦拉曼光谱技术采集了古代常用的蛋白类、多糖类、脂肪酸类、树脂类4类6种有代表性的天然有机物的拉曼光谱。通过对皮胶、桃胶、蜂蜡、棕榈蜡、达玛树脂和琥珀标准样品的拉曼光谱分析,发现蛋白类的特征振动峰位于1657cm-1、1305~1252cm-1、1033cm-1及1003cm-1附近;多糖类的特征振动峰位于1463cm-1、1328cm-1、1258cm-1、1088cm-1、977cm-1等;蜡类的特征振动峰位于1470~1350cm-1区间,1659cm-1、1303cm-1、1636 cm-1及1610cm-1;树脂类的特征振动峰位于1660~1650cm-1区间和1460~1440cm-1区间。在对6种天然有机物光谱特征分析的基础上,得出了使用拉曼光谱法可实现古代文物表面常见天然有机物种类鉴别的结论。     

The Intentional Use of Lead–tin Orange in Indian Islamic Glazes and Its Preliminary Characterization

We describe the historical appearance, composition and texture of a little‐known orange pigment in 17th‐century northern India. The pigment shares similarities with lead–tin yellow type II, but has between 6 and 7 wt% zinc oxide instead of silica as a minor element in its structure, in addition to the dominant lead and tin oxide. The consistency of its occurrence and composition across several important and highly decorated monuments and relatively wide chronological and geographical ranges of use indicate the controlled and intentional production of this pigment. We propose to use the name lead–tin orange for this material, indicating its similarity to lead–tin yellow but highlighting its independent character and distinct colour.     

Degradation of mud brick houses in an arid environment: a geoarchaeological model

A common assumption in Near Eastern tell archaeology is that the majority of sediments originate from degraded mud bricks. Little is known about the mechanism of mud brick wall degradation. Here we present a detailed macro- and microscopic ethnoarchaeological study of the degradation of a mud brick house and propose a comprehensive mechanism for tell formation processes in arid environments. The study took place in southern Israel by trenching a ca. 60 year old abandoned mud brick house, followed by extensive sediment sampling. Macroscopic observations showed that mud brick walls degrade by collapse of single bricks and/or collapse of intact wall parts, either inwards or outwards. In addition, infill sediments within the house and outside it, in close proximity to its walls, form alternating sedimentary layers of various colors and textures. The degraded mud brick material lost its distinctive macroscopic structure, which makes it impossible to accurately identify this material by field observations alone. Mineralogical and elemental analyses established the sources of the house infill sediments, namely mud bricks and wind blown sediments. Alternating layers mostly originate from mixing between degraded mud brick material and wind blown sediments. Micromorphological observations revealed microscopic mechanisms of mud brick degradation and include processes of mud slurry gravity flows, sediment coatings and infillings, wind abrasion of walls, small-scale puddling, and bioturbation. This study provides a working scheme for site formation of abandoned mud brick structures in arid environments. It provides a set of criteria by which it is possible to differentiate floors from post-abandonment sedimentary features and thus improves the reliability of activity area research.     

The Persistence of the Black Colour in Magnetite‐Based Pigments in Prehispanic Ceramics of the Argentine North‐West

The persistence of the black colour in magnetite‐containing paints in polychrome ceramics of the Argentine North‐West processed under conditions considered as oxidant has generated questions about ancient production technologies. In this work, the thermal oxidation reaction of magnetite to hematite under different temperatures, atmospheres and physicochemical characteristics of the materials is experimentally evaluated. The causes of this behaviour are elucidated, and it is concluded that in the archaeological context, a double‐firing process was not necessary to achieve the coexistence of different colours.     

Multi-method (FTIR,XRD, PXRF) analysis of Ertebølle pottery ceramics from Scania,southern Sweden

A combination of Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD) and portable X-ray fluorescence spectroscopy (PXRF) was used on the clay fraction of Ertebølle ceramics from several Late Mesolithic sites in Scania, southern Sweden. The aim was to provide up-to-date information about clay types used during that period within the Scanian Ertebølle cultural unit, and to elucidate social aspects relevant to the organization of pottery production and the role of ceramics in the local societies. The results suggest similar clay preferences across the sites, site-based pottery production using local clays and zero mobility of ceramics between the sites. The chemical separation of the ceramics from the site of Soldattorpet into two compositional groups suggests possible multigroup occupation. The origins of aromatic hydrocarbons, extracted previously from the ceramic matrix of the vessels during a lipid residue study, were also investigated, and a discussion is provided.     

Identification of Suspected Horn from the Queen Anne's Revenge (1718), North Carolina,USA

Infrared spectroscopy can be a valuable tool for conservators and archaeologists to help identify archaeological artefacts. We present a case‐study on the identification of an artefact recovered by North Carolina Department of Cultural Resources (NCDCR) Underwater Archaeology Branch from an early‐18th‐century shipwreck (31CR314). The wreck is assumed to be the remains of Queen Anne's Revenge, which sank off the North Carolina coast in 1718. A sample of the artefact was analysed by infrared spectroscopy to identify it. Prior to spectroscopic analysis it was speculated that the sample could be animal horn or leather. © 2011 The Authors     

便携式X射线荧光现场分析壁画颜料适用性研究——以西藏拉萨大昭寺壁画为例

便携式X射线荧光光谱仪作为快捷的无损分析技术,广泛应用于壁画文物的现场分析中.本文利用便携式X射线荧光光谱仪分析了西藏拉萨大昭寺转经廊壁画,选取部分样品,利用实验室X射线荧光分析,发现所分析颜料的主要显色元素具有一致性,并利用拉曼光谱确定了壁画颜料的成分.通过比较研究,发现便携式X射线荧光光谱仪可确定大部分色彩较为纯正的颜料的成分,同时,由于西藏拉萨大昭寺壁画颜料的杂多性,对于含砷的橙色颜料、含砷或含铅与含铁的黄色颜料、含铜砷的绿色颜料、含钙硫的白色颜料、群青与孔雀石的混合颜料则需结合拉曼光谱确定之.本研究工作显示,利用便携式X射线荧光光谱仪开展现场检测,可极大地减少实验室分析样品的取样数量,有利于壁画颜料的无损分析与微损分析.     

激光诱导击穿光谱分析法及其在彩绘文物分析与表征中的应用

激光诱导击穿光谱分析法是基于激光辐射与物质相互作用产生等离子体而进行实时、快速测定、表征的一种光谱分析新方法。其具有高灵敏度、高分辨率,分析速度快,样品用量少,无需样品预处理,一次光谱可测定多种元素组分等特点,且可在非破坏和非接触的条件下进行在线和实时分析测定,已广泛应用于材料、生物、环境、冶金、医学和文物等领域的测量和表征研究。本文从激光诱导击穿光谱分析法的基本原理、仪器装置及其在彩绘文物研究中的应用和进展进行了综述。     

Non-destructive chemical characterization of ceramic sherds from Shipwreck 31CR314 and Brunswick Town, North Carolina

The purpose of this study was to chemically and texturally characterize ceramic oil jar sherds from North Carolina Shipwreck 31CR314 and to explore the utility of environmental scanning electron microscopy/X-ray energy dispersive spectrometry (SEM/EDS) for that purpose. The oil jar sherds, widely dispersed about Shipwreck 31CR314, are morphologically similar to each other, which suggests they could be from a single jar, but with so few joins this could not be concluded with certainty. Therefore, an aim of this study was to investigate whether chemical or textural characterization of the sherds might reveal unique attributes that could distinguish individual jars; results of characterization perhaps could give information on their origin and possibly site formation processes, such as whether environmental forces could have scattered sherds of a single jar during and after sinking of the ship. Previous studies have indicated this shipwreck is likely the remnants of the Queen Anne's Revenge, flagship of the pirate Blackbeard. Sherds from this shipwreck were compared with similar oil jar sherds excavated from a land site, Brunswick Town, North Carolina, to explore the use of composition and texture as hallmarks. The chemical components of the artifacts were determined by SEM/EDS. This method of analysis is valuable for archaeological research because it is rapid and non-destructive to the ceramic artifacts. Both groups of lead-glazed coarse red earthenware sherds were texturally similar except for the glazed sides of all 31CR314 sherds that exhibited small tracks of unique crescent-shaped marks. These marks may be due to manufacturing effects and immersion in seawater, and the marks may serve as hallmarks for individual jars or potentially individual manufacturers. The sherds were generally similar in composition, but the two groups exhibited distinct differences. Brunswick Town sherds consistently contained more phosphate on unglazed sides, an average 1.46 wt.% P₂O₅, and also contained trace elements not detected in the Shipwreck 31CR314 sherds. These distinct differences could be due to different manufacturing origins for Shipwreck 31CR314 and Brunswick Town ceramics but also could reflect their subjection to different environments during use and loss prior to archaeological recovery.