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1.
Fluid inclusions of the H2O‐NaCl‐CaCl2 system are notorious for their metastable behavior during cooling and heating processes, which can render microthermometric measurement impossible or difficult and interpretation of the results ambiguous. This study addresses these problems through detailed microscopic examination of synthetic solutions during cooling and warming runs, development of methods to enhance nucleation of hydrates, and comparison of microthermometric results with different degrees of metastability with values predicted for stable conditions. Synthetic H2O‐NaCl‐CaCl2 solutions with different NaCl/(NaCl + CaCl2) ratios were prepared and loaded in fused silica capillaries and glass‐sandwiched films for microthermometric studies; pure solutions were used with the capillaries to simulate fluid inclusions, whereas alumina powder was added in the solutions to facilitate ice and hydrate crystallization in the sandwiched samples. The phase changes observed and the microthermometric data obtained in this study have led to the following conclusions that have important implications for fluid inclusion studies: (i) most H2O‐NaCl‐CaCl2 inclusions that appear to be completely frozen in the first cooling run to ?185°C actually contain large amounts of residual solution, as also reported in some previous studies; (ii) inability of H2O‐NaCl‐CaCl2 inclusions to freeze completely may be related to their composition (low NaCl/(NaCl + CaCl2) ratios) and lack of solid particles; (iii) crystallization of hydrates, which is important for cryogenic Raman spectroscopic studies of fluid inclusion composition, can be greatly enhanced by finding an optimum combination of cooling and warming rates and temperatures; and (iv) even if an inclusion is not completely frozen, the melting temperatures of hydrohalite and ice are still valid for estimating the fluid composition. 相似文献
2.
About 200 analyses have been made on late Roman and Sassanian silver objects using energy-dispersive X-ray fluorescence. This has shown that the main feature of the composition of the silver throughout the period and across the geographical area studied was towards high fineness (average silver percentage about 95%). Compositional differences are found between Roman and Sassanian silversmiths' products for the elements copper and lead. Much of the material analysed came from hoards, and using a statistical technique on the analytical data (Discriminant Analysis) broad compositional differences between hoards were found to emerge. The use of different compositions of silver for different joined parts of a single object are discussed. 相似文献
3.
A. Bonneau J. Moyle K. Dufourmentelle D. Arsenault C. Dagneau M. Lamothe 《Archaeometry》2017,59(5):834-851
Dating is perhaps the most frequently asked question in rock art studies, but still one of the most difficult to answer. However, chronology is vital in order to understand and interpret rock art sites. Unfortunately, attempts at dating the Mikinak site, at Lake Wapizagonke, Quebec, Canada were unsuccessful. But a multi‐instrumental protocol applied to characterize paintings shows that at least three different paint recipes were employed to create the site. These may reflect three different phases of paintings, and that at least three different artists contributed to the production of this site. 相似文献
4.
弦歌台又被称为绝粮祠,整体布局以中轴线为中心呈现东西对称,现存建筑的规制为三进院落,从南向北依次为正门、戟门、大成殿、弦歌书院。大成殿作为弦歌台最核心的建筑,外观气势宏伟,彩绘精美绝伦,是我国东部地区规格较高的孔庙建筑之一。弦歌台大成殿在自然环境和人为因素的长期影响下,彩绘表面出现了褪色、龟裂、颜料脱落等多种病害,彩绘修复工作已成为当前文物保护亟待解决的棘手问题。本工作对彩绘样本的层位和形制进行详细分析,从剖面和表面等多角度进行全面研究,发现大部分彩绘样本由内向外的结构依次为基底层、地仗层、颜料层,蓝色彩绘样本所使用的地仗层为传统的单披灰工艺,与之不同的是红色彩绘样本为无地仗彩绘,红色颜料层直接绘制于基底层上,推测这可能与时代的发展及工艺的变化有关。为了更好地服务文物进行科学保护,需要了解大成殿彩绘颜料成分及制作工艺等。采用超景深微观分析、扫描电镜及能谱仪分析、显微拉曼光谱分析等现代技术及方法,对彩绘颜料样本进行了层位结构、微观及成分检测分析。结果表明,在制作工艺上,大成殿彩绘颜料层剖面多为两层以上叠加,是明显的重层彩绘,说明历史上至少经历过两次以上重绘。同时发现大成殿彩绘颜料层既有重... 相似文献
5.
A. Ong J. Pironon P. Robert J. Dubessy M.‐C. Caumon A. Randi O. Chailan J.‐P. Girard 《Geofluids》2013,13(3):298-304
Accurate reconstruction of diagenetic P‐T conditions in petroleum reservoirs from fluid inclusion data relies on valid measurements of methane concentration in aqueous inclusions. Techniques have been developed (Raman spectrometry) to provide sufficiently accurate data, assuming measured methane concentration has not been modified after aqueous inclusion entrapment. This study investigates the likelihood that organic acids derived from petroleum fluids and dissolved in formation water might suffer decarboxylation upon postentrapment heating within the fluid inclusion chamber, thereby generating excess CH4 in the inclusions. Four different experiments were conducted in fused silica capillary capsules (FSCCs), mimicking fluid inclusions. The capsules were loaded with acetic (CH3COOH) or formic (HCOOH) acid solution and were heated to 250°C for short durations (<72 h) in closed‐system conditions, with or without applying a fixed PH2. Reaction products were characterized by Raman and FT‐IR spectrometry. Results indicate that decarboxylation reactions did take place, at variable degrees of progress, and that measurable excess CH4 was produced in one experiment using acetic acid. This suggests that methane may be produced from dissolved organic acids in natural aqueous inclusions in specific situations, possibly inducing errors in the thermodynamic interpretation. 相似文献
6.
山东危山西汉墓出土陶器彩绘颜料研究 总被引:6,自引:4,他引:2
为研究山东危山西汉墓出土彩绘陶器颜料成分,采用偏光显微镜、显微拉曼光谱仪和扫描电子显微镜-能谱仪进行了分析。研究结果显示,危山汉墓陶器彩绘颜料有朱砂、铅丹、中国紫(汉紫BaCuSi2O6)、铁红、铁黑、白土等。中国紫颜料首次在山东省的发现,扩大了该颜料的使用区域,具有重要的考古学意义。另外,还在紫色颜料中分析出了BaCu2Si2O7蓝色晶体,这是继中国蓝中国紫之后的又一重大发现。 相似文献
7.
J. P. Ogalde A. Korpisaari C. Riera‐Soto B. Arriaza C. Paipa P. Leyton M. Campos‐Vallette N. Lara J. Chacama 《Archaeometry》2021,63(1):53-67
The chemical and mineralogical characterization of seven ceramic fragments produced within Tiwanaku state (c.500–1000 ce ) is reported. The instrumental techniques used included X‐ray elemental and mineralogical chemical analysis, Raman spectroscopy, and scanning and light microscopy. The results indicate there are several clay types, although they show similarities, such as the use of a plant‐based temper. The red colour of the decoration is hematite, and manganese oxides such as jacobsite are present in the black. The white colour is a mixture of gypsum and clay, and the orange is a mixture of hematite and clay. The use of colours, the quality of the clays and the temperatures reached during pottery firing point to expertise in ceramic production and to complex decision‐making processes. The multi‐elemental archaeometric approach documented here could become an important tool to shed a light on ancient ceramic technology and the internal variance of Tiwanaku pottery. 相似文献
8.
Kevin D. Ingram Kenneth E. Daugherty James L. Marshall 《Journal of archaeological science》1993,20(6)
Several samples of pyramids from Giza were obtained. The samples were analysed by scanning electron microscopy, electron diffraction by X-rays, powder X-ray diffraction, inductively coupled plasmography, Fourier-transform infrared spectroscopy and other techniques. Some scientists who have recently studied the pyramids have suggested that the pyramids were poured into place, stone by stone. The prevailing theory among Egyptologists is, of course, that the pyramids were built from blocks of natural stone. All of the results obtained during this study directly support the concept that the pyramids are made of limestone and are not cementitious in nature. 相似文献
9.
Scanning electron microscopy/energy dispersive X-ray analysis has earlier shown that the white background layer (slip) on painted pottery sherds (Yangshao culture, Henan, China, 4200 BC) is composed of kaolinitic clay containing titanium in the assumed form of TiO2 at just 1 wt%. The same samples of white slip have now been studied by Raman microscopy, revealing bands characteristic of anatase, but none from the majority species, the matrix of kaolinitic clay. These results highlight the extraordinarily intense Raman scattering from even trace amounts of anatase and thus the need to recognise that, although the colours of archaeological artefacts are almost always determined by the nature of the matrix, the Raman spectrum may be determined by a highly scattering trace component such as anatase. The significance of anatase as a potential date-marker pigment on works of art and archaeological artefacts is discussed. 相似文献
10.
本文利用激光拉曼光谱仪和能量色散X-射线荧光光谱仪对21件取自故宫博物院院藏宋代官窑完整器及42件取自杭州老虎洞官窑窑址的青瓷样品表面釉层进行了测量与分析。通过计算瓷釉样品拉曼光谱中位于500cm-1附近宽带与位于1000cm-1附近宽带的面积比值(Ip值)及利用EDXRF分析样品的元素成分,讨论了这些样品的主要助熔剂成分Ca O、K2O含量与Ip值之间的关系,并通过对成分具有两类典型官窑瓷器釉料特征且在不同烧成温度下烧制的模拟釉块进行拉曼分析,对宋官窑青瓷样品的釉烧温度进行了讨论。 相似文献