Raman microprobe analysis of stucco samples from the buildings of Maya Classic Copan

Micro-Raman spectroscopy has been applied to painted stucco samples from three buildings at the Maya site of Copan, Honduras. The buildings, Clavel (AD 450–550), Ani (AD550–650) and Structure 10L-22 (AD730,) date from three phases of the Classic Period (AD400–820) acropolis construction. The red pigment has been identified as haematite and the stucco as a mixture of calcite particles dispersed throughout a calcite based lime wash stucco. The physical structure of the stucco changed through time, indicating a refining of production techniques over this period. By combining Micro-Raman spectroscopy with other micro-ATR infrared spectroscopy and environmental scanning electron microscopy a detailed investigation of the materials and production techniques used to decorate these buildings has been made. Differences in the mineralogy of the red pigment used on each building indicate a different geological pigment source for each period.     

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.     

Evaluating copper isotope fractionation in the metallurgical operational chain: An experimental approach

Until today, raw material information of copper (Cu) objects is mostly gained from impurities and trace elements and not from the Cu itself. This might be obtained using its stable isotopes. However, isotopic fingerprinting requires the absence of fractionation during the smelting process. The Cu isotope evolution during outdoor smelting experiments with Cu sulphide ore was investigated. It is shown that external materials, in particular furnace lining, clay, manure and sand, alter the isotopic composition of the smelting products. Cu isotopes are fractionated within low viscosity slag derived from matte smelting. The produced metallic Cu has a Cu isotope signature close to the ore.     

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.     

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.     

阿尔寨石窟壁画颜料的拉曼光谱分析

本文利用拉曼光谱对内蒙古阿尔寨石窟壁画不同颜料进行了鉴定和分析。结果表明．绿色颜料为碱式氯化铜、蓝色颜料为蓝铜矿、白色为方解石、红色为朱砂、黑色为碳黑。这为阿尔寨石窟壁画进行研究及保护工作提供了科学的依据。同时也表明,拉曼光谱简便、快速、对样品要求量小．对样品无损分析,符合文物材质分析的要求,并可得到准确的信息。     

Identification of psychoactive alkaloids in ancient Andean human hair by gas chromatography/mass spectrometry

Various ethnographic sources have demonstrated the symbolic and ritualistic importance of psychoactive plants in Native American societies. The social milieu of these mind- altering plants appears to be ancient. Archaeological evidence during the Tiwanaku empire expansion along the Atacama Desert of Chile, circa 500–1000 A.D., shows the presence of highly decorated snuffing tablets and tubes as grave goods. The preservation of mummified human bodies in the Azapa Valley, northern Chile, provided an opportunity to test the exact nature of the psychoactive plants used in this region. Using gas chromatography/mass spectrometry (GC–MS), here we show that ancient Andean populations from northern Chile consumed Banisteriopsis, a vine that contains harmine. This is the first direct archaeological evidence of hallucinogenic and medicinal ethnographic practices. Interestingly enough, this rainforest plant does not grow along the Atacama coast, thus our findings suggest extensive plant trade networks in antiquity as far as the Amazon.     

U/Th-rich bitumen in Archean granites and Palaeoproterozoic metasediments, Rum Jungle Mineral Field, Australia: implications for mineralizing fluids

Uranium/thorium (U/Th)‐rich bitumen has been discovered within both Palaeoproterozoic black pelites and the Archean granitic basement of the Rum Jungle Mineral Field, Northern Territory, Australia. Granite‐hosted bitumen occurs as small (up to 400‐µm diameter) discrete individual nodules, which exhibit many morphological similarities to those observed in Phanerozoic siliciclastic rocks. Thorium, the dominant radioelement, occurs primarily as a hydrated Th–Y–Si–P phase. Uranium‐rich inclusions are rare, and correspond to a hydrated U–Th–Y–Si–P phase, identified as coffinite–thorogummite. Metasediment‐hosted bitumen is more variable in morphology, occurring as massive (<2 cm in width) veins that cross‐cut all foliations, as discrete individual nodules or as elongate seams (up to 500 µm in length), interpreted to represent a series of coalesced individual nodules. In all examples, uranium, the dominant radioelement in the metasediment‐hosted bitumen, is present as Th‐poor uraninite, with variable Y₂O₃ contents (up to 3.21 wt.%). Raman investigation of all types of bitumen indicates that it is a poorly organized carbonaceous matter, which has not been subjected to metamorphism. Consequently, a post‐metamorphic timing for hydrocarbon emplacement can be inferred and a magmatic origin can be precluded. Potential source rocks for the bitumen are black shales of the Whites Formation (up to 8 wt.% total organic carbon (TOC)) and the Koolpin Formation (approximately 13 wt.% TOC). Post‐metamorphic sericitization of rocks within the Whites Formation is accompanied by a near‐complete removal of organic matter. Alteration was possibly the catalyst for hydrocarbon generation. The Th–Y–Si–P phase within the granite‐hosted nodules is interpreted to be the result of the alteration of antecedent monazite. During this alteration, U, LREE and P were fractionated and removed, while Th, Y and Si remained immobile, and recombined to form a hydrated Th–Y–Si phase. This pervasive alteration within the basement U/Th‐rich granites is proposed as a genetic model for the formation of uranium deposits in the Rum Jungle Mineral Field and possibly unconformity associated uranium deposits on a global scale.     

The production technology of Egyptian blue and green frits from second millennium BC Egypt and Mesopotamia

The microstructures and chemical compositions of some 55 Egyptian blue and green frit samples from New Kingdom Egypt and 15th century BC Mesopotamia are determined using analytical scanning electron microscopy, the main focus being on frit cakes, powder residues, and frit vessel and bead fragments from one of the “factory areas” at Amarna in Middle Egypt. Replicate Egyptian blue frits produced in the laboratory are similarly investigated. Comparison of the microstructures of the ancient and replicate samples suggest that frit cakes are the primary product, and that these were ground to produce the powder, and then moulded to shape and refired to produce the vessels and beads. Egyptian blue and green frits are shown to be distinct pigments, the pigment produced depending on the relative proportions of copper oxide and lime in the mixtures. The bulk and glass phase compositions are used to try to infer the different sources of the quartz, lime, copper and alkali flux used in the production of frits from Egypt and Mesopotamia. An estimate is made of the scale of production of Egyptian blue frit in New Kingdom Egypt.     

横岭山商周时期玉器的质地、白化现象和玉料产地研究

为研究广东博罗横岭山商周时期墓地出土玉器的质地、白化现象和玉料产地,对玉料样品进行常规矿物学、红外光谱、X射线粉晶衍射、扫描电镜和拉曼光谱的测试。结果显示,该墓地出土玉器的材质包括石英、水晶、透闪石（软玉）和杂砂岩。其中,透闪石质的玉器呈白色、不透明的外观,被认为和酸性土壤的腐蚀有关;出土的石英质玉器（含水晶器）的包裹体特征及包裹体均一温度显示该墓地出土的石英质玉器（含水晶器）的玉料较可能来自变质石英岩。伟晶岩或高温石英脉,将其与博罗本地、台山地区（近环珠江口地区）的石英及水晶样品进行对比,未有证据显示该墓地出土的石英质玉器（含水晶器）的原料来自上述地区。本研究可为揭示商周时期珠江三角洲地区的先民对自然资源的认识和利用能力以及当时社会的生产力水平、物品交换及贸易路线等方面提供基础科学依据。