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.     

内蒙古阿尔寨石窟壁画制作工艺和颜料的分析研究

为了解阿尔寨石窟壁画的制作工艺和颜料成分,采用偏光显微镜分析、剖面分析,并结合X射线衍射分析对6个洞窟的23个样品进行了分析。为了进一步研究阿尔寨石窟壁画颜料,还通过偏光显微法对其他地区和年代的壁画颜料进行了对比研究。结果表明,其绘制方法是先用加有麦秸的粘土将洞窟壁面抹平,然后用石灰涂白。再施以彩绘。所使用的颜料为矿物质颜料,多为绿、白、红、蓝色等。其绿色颜料为氯铜矿,白色颜料为碳酸钙,红色颜料为朱砂和铅丹,蓝色颜料为石青。     

青海民和县出土马家窑文化彩陶的科学分析研究

为了解青海民和回族土族自治县(以下简称民和县)阳山墓地(半山类型)和马牌墓地(马厂类型)出土的马家窑文化彩陶颜料成分及制作工艺,采用偏光显微技术、显微拉曼光谱、X射线衍射及扫描电镜-能谱对其进行综合分析。结果表明:民和县马家窑文化彩陶黑彩的呈色物相为磁铁矿和黑锰矿;红彩的呈色物相为赤铁矿;白彩的呈色物相为石英;黑彩的Fe/Mn比值,从半山时期的0.31增长到马厂时期的2.45左右,Fe/Mn比值呈现上升趋势。民和县铁矿颜料的应用是继化隆县纳卡遗址发现的又一实例,为研究矿物颜料在甘青地区史前时期彩陶中的使用历史提供重要的线索。结合地质文献资料,推测青海民和县所使用的矿物颜料为就近取材。陶胎岩相主要由石英、长石、角闪石及碳酸钙组成;以强烈铁染为特征;孔隙较多,大多拉长定向分布;在900℃左右焙烧成器。在此基础上将对甘肃和青海地区史前彩陶岩相组成进行对比研究,深入探析彩陶贸易及陶器产地信息,进而为陶器的研究与保护提供依据。     

Pb and Sr Isotopes and the Provenance of the Painting Materials of Cornelius Krieghoff in 19th‐Century Canada

Radiogenic lead and strontium isotope data are presented for lead‐ and calcium carbonate/barium sulphate‐containing paint and ground samples from 15 paintings, executed between 1844 and 1871, by 19th‐century Canadian artist Cornelius Krieghoff. Like many artists of this era, Krieghoff used lead‐based pigments such as lead white, chrome yellow and Naples yellow, and extenders such as calcium carbonate and barium sulphate. The lead isotope analyses of the majority of these pigments are consistent with the isotopic compositions of lead mined from European lead deposits in England and/or Germany. However, three samples from Krieghoff's early career yield lead isotope compositions that are much more radiogenic than European sources. The lead isotope compositions of these three samples are consistent with the addition of a more radiogenic lead component that is similar to the lead derived from North American lead deposits in Missouri and Illinois (Mississippi Valley Pb–Zn type deposits). The strontium isotope compositions of the extenders suggest that the raw materials for calcium carbonate or barium sulphate extenders were largely derived from Palaeozoic to modern‐day marine environments. This study shows that pigments manufactured from North American lead were being incorporated into Canadian paintings as early as 1844.     

基于铅同位素比值的古代矿料混合模型分析法

为深入研究古代青铜器示踪矿料来源中矿料混合问题,通过铅同位素研究数据构建矿料混合模型,从理论上探讨满足条件的青铜器数据样本其矿料混合的情况。基于模型,通过对铅同位素数据的处理,不仅能够匹配相应的矿料混合模式,而且可为器物分类提供依据。此外,还可计算出相应的铜料中表观含铅量,为相关研究提供参考依据。     

馆藏唐代彩绘人物俑颜料分析与修复保护

为确定深圳博物馆藏唐代彩绘人物俑颜料的矿物成分,利用X射线荧光能谱仪、X-射线衍射仪等对这批俑的颜料成分进行了分析,结果表明:红色颜料为铅丹、朱砂;黑色颜料为无定形碳黑;白色颜料为铅白和高岭土等.同时,将其与陕西省内相关地区的彩绘陶俑或壁画颜料进行了对比,得知其所使用的颜料与后者基本一致.在此基础上,针对这批人物俑的保存现状,遵循最小干预等文物保护的基本原则,对其实施了表面附着物清理、拼对、粘接、修复补全等保护修复技术措施,使其恢复了原有面貌,取得了较为理想的保护效果.     

千手观音试验区的彩绘修复研究

本文详细地调查了试验区域的法器和彩绘的病害,对彩绘的病害机理和绘制工艺进行了研究,确定了修复技术路线和修复工艺.此次修复研究的重点放在法器和彩绘的补色上,在补色过程中遵循了全彩的原则.针对法器彩绘残存不同的情况,本文采用三种不同的补色方案,并通过研究总结出法眼和背景云纹的补色规律.     

皖南沿江地区部分出土青铜器的铜矿料来源初步研究

根据要想追溯青铜器铜矿料来源,必须先了解古铜矿及其冶炼金属产物的微量元素和同位素特征,研究其输出方向这一思路,以前期提出的以较高含量的Se、Te、Ni(Co／Ni大多小于1)、Ag、Au等及相对低含量的Sb、Bi、Mo等作为安徽铜陵等地古铜矿冶炼产物一铜锭产地的特征指示元素为综合判别标志,用等离子发射光谱仪对皖南沿江地区出土的部分青铜器进行多元素分析。结果表明,样品Tc2007、Tc2005、fc12所用铜料不大可能来自铜陵地区,其余样品可能来自当地。鼎、(虚瓦)等大件样品可能在其它地区铸造后传人本地。研究结果说明,利用微量元素判断青铜器铜矿料来源是可行的。     

A technological transition in Mongolia evident in microstructure,chemical composition and radiocarbon age of cast iron artifacts

Metallurgical examination of cast iron objects from the Khitan period (AD 10th–12th) in Mongolia shows that they might be classified into two groups. The first is based on Fe–C alloys of near eutectic composition and the second is based on Fe–C–Si alloys with reduced carbon content and numerous sulfide inclusions. By contrast, all the objects from the succeeding Mongolian empire period (AD 12th–15th) belong to the second group, indicating that a technological transition had occurred during the Khitan period. Accelerator mass spectrometry (AMS) on carbon samples extracted from artifacts in both groups and measurement of alloy compositions suggest that the use of mineral coal in smelting was a major factor for this transition.     

A comparative study of wall paintings at the Cypriot monastery of Christ Antiphonitis: one artist or two?

The central church of the monastery of Christ Antiphonitis near Kalogrea, within the district of Kyrenia in Cyprus, is decorated with wall paintings that date from the last decades of fifteenth century. Two large and elaborate scenes, the Last Judgement and the Root of Jesse, had been preserved in the church until the Turkish invasion (1974) after which they were cut into tetragonal pieces, separated, and sent by looters to Germany for selling at illicit markets. The German Police returned thirty-two of the pieces to the Archbishop Makarios Foundation in Nicosia.