劣化石刻表层生物矿化加固材料的探索性研究

许多濒危石质文物表层劣化现象严重。但是,以往使用的表层加固材料很难令人满意,探索新的疏松岩石表层加固材料已是当务之急。由于天然生物矿化物耐候性优越,与基底岩石相容性良好,具有较好的加固作用,本工作依据生物矿化的原理,以不同生物大分子溶液作为有机模板,分别控制草酸钙、磷灰石和碳酸钙过饱和溶液于室温下在疏松岩石仿制样品的表层及孔隙内结晶生长。通过抗压强度、表面硬度和耐水浸泡等试验进行了加固效果评价,以考察仿生物矿化材料对含钙疏松岩石的加固能力。实验结果表明,仿生合成的生物矿化材料均具有一定的加固效果,其中以磷灰石仿生矿化材料的加固强度最大,以硫酸软骨素为模板的加固效果为佳。并且,在考察的3种加固方式中,以"直接混合"的加固强度更好,以"表面渗透"的耐水浸泡能力更强。本工作为开发濒危石质文物表层加固材料提供了新的思路。     

Chemical and mineralogical characterization of Aguada Portezuelo pottery from Catamarca,north-western Argentina: PIXE,XRD and SEM-EDS studies applied to surface pre- and post-firing paints,slips and pastes

Particle-induced X-ray emission (PIXE), X-ray diffraction (XRD), electron microprobe analysis (EDS) and scanning electron microscopy (SEM) analytical techniques were used to characterize surface paints in pre- and post-fired Aguada Portezuelo decorated pottery. Surface paintings in black, white, red, brown, burgundy and ochre were analysed. Major, minor and trace elements were detected by PIXE, whereas XRD and SEM-EDS gave information on the main mineral phases and the characteristic morphology for each analysed pigment. The results obtained indicate that the main colour groups can be easily discriminated by PIXE, and they are characterized by only one pigment for each colour: hematite (red) and manganese mineral oxides (black), respectively, whereas white pigments are characterized by calcite, ghelenite and gypsum.     

Early Islamic pigments at Nishapur,north-eastern Iran: studies on the painted fragments preserved at The Metropolitan Museum of Art

Pigments appearing on ninth–twelfth-century AD-carved stucco, wall painting, and terracotta friezes excavated at Nishapur in north-eastern Iran were investigated by optical reflectance spectroscopy, micro X-ray fluorescence spectrometry (μ-XRF), X-ray diffractometry (XRD), micro-Raman spectroscopy (μ-Raman), and scanning electron microscopy (SEM). Many of the pigments identified including vermilion, red lead, hematite, limonite, carbon black, atacamite, calcite, and gypsum have been identified in previous studies of pigments used in later Islamic periods. However, a series of unusual pigments such as wulfenite, pyromorphite, phoenicochroite, and jarosite were also found in the present study. The association of kaolinite and alunite with limonite and other Fe-bearing yellow pigments points to a local provenance for these pigments. In addition, the presence of orpiment in the vermilion may be indicative that the vermilion was artificially manufactured. These findings suggest that pigment use and manufacturing during the ninth to eleventh centuries in Nishapur was still in a trial-and-error stage and the palette known from the twelfth century onwards had not yet been systematized.     

Differentiating between anthropogenic calcite in plaster,ash and natural calcite using infrared spectroscopy: implications in archaeology

Infrared spectroscopy provides information not only on the type of calcium carbonate polymorph, but also on the extent of atomic order. In calcite, three major infrared absorption peaks are identified: ν₃, ν₂, and ν₄. It was shown that the ratio between ν₂ and ν₄ bands reflects the order of the calcite crystal structure. In this paper we analyse this ratio in geologically formed calcites, archaeological plasters, modern plasters and experimentally prepared plasters. For the geological calcite, the values of the ν₂/ν₄ ratio are around 3, whereas for the experimentally prepared plasters, the values are around 6.5. The ν₂/ν₄ ratio for archaeological plasters varies from 3 to 6. This shows that a high ratio is indicative of disorder in the crystal, and implies that the calcite was formed from calcium oxide at high temperatures. It also implies that this disorder can be preserved for at least 14,000 years. The ν₂/ν₄ ratio of calcite from archaeological sites can thus be used to differentiate between anthropogenic calcite, such as in plaster, mortar and wood ash, from geogenic calcite, such as in limestone. The ratio may also be used to identify plaster or ash that still retains its original crystals and therefore carbon-14 content.     

Moisture content measurement and surface water absorption test in the inner gallery of Bayon for the conservation of the bas-relief

The bas-relief carved on the sandstone wall in the central part of the inner gallery of Bayon in the Angkor monuments, Cambodia, has been severely damaged mainly due to calcite crystallization. In order to confirm the mechanism of salt weathering and help determine conservation measures for the bas-relief, measurements of the annual change in the moisture content in the bas-relief were conducted. We found that water supplied from the platform behind the bas-relief is the cause of calcite crystallization. It is therefore indispensable for the conservation of the bas-relief to prevent the water permeating from the inside of the platform behind it. As precipitated calcite from the water block pores near the surface of the sandstone, the surface water absorption test is a useful method to evaluate the degree of the salt weathering.     

Scientific study of the pigments and binders used in mural painting from the 16th-century ce St Mary's Church of Cheriapally,Kottyam, Kerala,and its relevance to conservation

The aim of this investigation was to analyze the materials and techniques of the paintings in the 16th-century ce St Mary's Church, to evaluate deterioration of the paintings, and to propose a suitable conservation treatment for their preservation. The material analysis of ground, pigments, binders, and plasters was undertaken using binocular microscopy, field emission scanning electron microscopy (SEM)–energy dispersive X-ray spectroscopy, X-ray fluorescence, Fourier transform infrared spectroscopy in reflectance (KBr) and transmittance mode (attenuated total reflection), thin-film X-ray diffraction, and micro-Raman spectroscopy. Gas chromatography–mass spectrometry (GC-MS) was used for identifying proteinaceous and lipidic materials extracted from the micro-samples. The study generated data on two different red and green pigments used as decorative materials. The red pigments were identified as cinnabar along with traces of hematite and clay minerals, and green as malachite and the minor presence of other minerals. SEM analysis identified cotton fiber embedded in the coarse plaster layer that provided better strength to the plaster. Plant oils and proteins found as the binder in the pigment samples suggested that the painting technique was executed as tempera. Lead white and gypsum materials were used in previous restoration works.     

天梯山石窟9窟彩塑与壁画地仗矿物 及颜料分析

天梯山石窟,即北凉石窟,在国内史学界誉为中国古代石窟鼻祖。据考证,9窟彩塑与壁画制作始于唐代,后经历代多次重绘。针对目前彩塑与壁画的保存现状及需要修复的状况,本研究运用现代分析仪器与技术,对9窟现存的彩塑、壁画进行了科学分析。其中,对彩塑及壁画地仗土层矿物进行了X射线衍射分析,对重层彩绘颜料进行了X射线衍射、X射线荧光分析;另外,对清理彩塑地仗时发现的植物茎秆及附属物,采用偏光显微分析技术进行了材质鉴定。分析和鉴定结果表明:9窟现存彩塑及壁画地仗土层具有相同的矿物组成,基本包括石英、长石(斜长石、少量的K-长石)、云母(白云母、绿泥石、伊利石、斜绿泥石)、方解石、少量石膏,并确定植物茎秆材质为稻草;在使用的彩绘中,黑色为墨,红色颜料有朱砂、铅丹和铁红,蓝色颜料为石青,白色颜料以方解石为主,有少量的石膏。本结果可为后期天梯山石窟的全面复原修复提供参考资料。     

Physico‐Chemical Characterization of Pigments and Binders of Murals in a Church in Ethiopia

Here, we report the physico‐chemical characterization of wall paintings from the Petros and Paulos church in Ethiopia. This work represents the first technical study of paintings located in Ethiopia, rather than paintings in museum collections outside the country, using diverse analytical techniques. In situ examination with a portable X‐ray fluorescence spectrometer (pXRF) was followed by analysis of samples using optical microscopy (OM), scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy (SEM/EDS), micro‐Raman spectroscopy (MRS), attenuated total reflection – Fourier transform infrared spectroscopy (ATR‐FT–IR), X‐ray powder diffraction (XRD) and pyrolysis gas chromatography – mass spectrometry (Py‐GC/MS). The paint stratigraphy, the compositions of the support material, the preparatory and painting layers were studied, as well as the morphology of the pigment particles. The results revealed the use of earth pigments and carbon black. The preparatory layer was uncommon; composed of dolomite, clay rich in clinochlore and sand, in contrast to the more common gypsum and calcite. The binder and the stratigraphic analyses suggested a distempera technique.     

Painted plaster from Bronze Age Thebes, Boeotia (Greece): a technological study

From the rather difficult excavations that have taken place in Thebes since the beginning of the last century, many fragmentary but often well-preserved paintings on plaster have been unearthed. These belong to several contexts and periods: House of Kadmos (Late Helladic IIIA), Treasury Room (Late Helladic IIIB1) and Oikopedon Spourli (Late Helladic III). Their iconography, style and technology fit well with other paintings from the Late Bronze Age sites found in the vicinity of Thebes (e.g. Gla and Orchomenos). This paper presents a technological study of the Bronze Age painted plaster from Thebes, Greece. The paintings were investigated by means of X-ray diffraction; stereo, reflected light and scanning electron microscopy; some by laser-induced breakdown spectrometry and by micro-Raman spectroscopy, in order to identify the pigments and the composition of the plaster layers, and to determine the painting technique(s) that the artisans may have employed. The plaster layer onto which the paint layer was applied was often the only layer and consisted mainly of calcite, while a clay plaster formed the backing between the lime plaster coat and the actual wall surface. The pigments identified were: yellow ochre, haematite (red), cuprorivaite (Egyptian blue), indigo and possibly riebeckite for blue, charcoal (black), calcite (white), and a combination of black and red for purple. A detailed macroscopic study of the painted surface revealed several features, which indicated that the technique of al fresco painting was employed extensively, a technique already in use since the start of the Late Minoan I phase on Crete. A generally lower level of quality in the appearance of the later paintings (Treasury Room and Oikopedon Spourli) was also noted, but this was not reflected in the materials used or in their overall manipulation.     

Archaeometric study of natural hydraulic mortars: the case of the Late Roman Villa dell’Oratorio (Florence,Italy)

This paper shows the results of a multidisciplinary study carried out on the mortars from the Late Roman Villa dell’Oratorio (fourth-sixth ad), an aristocratic mansion built in the lower Valdarno (Florence, Italy). Thirty-one bedding mortar and plaster samples were analysed through optical microscopy, thermogravimetric analysis, X-ray powder diffraction and scanning electron microscopy with energy-dispersive X-ray spectroscopy for determining the chemical, mineralogical and petrographic characteristics, while their main physical properties were measured by geotechnical procedures. The collected data indicates that the analysed mortars are made up of very fine to coarse river sand aggregate mixed with white to yellowish-white natural hydraulic lime binder mainly consisting of mixtures of prevailing calcite and hydraulic compounds. With regard to the origin of the raw materials, the aggregates were recognized to be selected Arno river sands, and the binders are the burning product of a local marly limestone (ex Alberese). Therefore, the mortars of the Late Roman Villa dell’Oratorio are one of the first uses of natural hydraulic lime in the lower Valdarno.     

龙门石窟张夏组鲕粒灰岩特征及溶蚀试验研究

张夏组碳酸盐岩是龙门石窟主要造窟地层,水岩作用强烈。近年来酸雨进一步加剧了龙门石窟碳酸盐岩的溶蚀。为了对龙门石窟的保护提供相关资料,需进一步探讨鲕粒灰岩的抗风化能力。为此,对东山石窟区所在张夏组分层、取样,进行成分、微观结构分析,并通过室内酸雨溶蚀模拟实验来研究张夏组地层的溶蚀规律。研究表明,龙门石窟张夏组各地层溶蚀差异较大,其单位面积溶蚀质量与钙镁比正相关;鲕粒灰岩风化后表面粗糙度与鲕粒含量密切相关;研究区张夏组鲕粒成分主要为白云石,鲕粒灰岩的抗化学侵蚀能力比普通灰岩更强。通过对张夏组地层岩性的分析及其溶蚀规律的研究,为龙门石窟的保护提供了基础科学资料。     

徐州狮子山汉楚王陵彩绘陶俑的保护研究

为对徐州狮子山出土的彩绘陶俑进行保护,我们对陶俑本体进行了分析,采用扫描电子显微镜（SEM）对陶俑表面进行微观形貌分析;X射线荧光光谱仪（XRF）分析化学成分;通过岩相分析,并结合XRD分析、热重和差示热分析（TG-DSC）从而推测陶俑的烧成温度;电子能谱仪（EDS）对彩绘表面颜料的进行成分分析。在此基础上,采用7种化学材料进行对比实验,对外观、颜色光泽度变化、固化物形成期、防水接触角、吸湿等温线、吸水率、抗压强度进行了观察和分析,同时,还进行了紫外光耐老化试验。试验表明,氟橡胶不仅有较好的渗透率和膜层外观及相对较强的抗压能力的优点,而且还有较好的耐老化性能。经过对狮子山出土的一尊彩绘陶俑利用氟橡胶进行保护后10多年的观察,陶俑的表面色泽、防水与接触角、颜料表面的固结强度等状态保持良好。因此,在保护彩绘陶俑方面,氟橡胶是值得考虑的一种材料。     

STUDY ON THE PIGMENTS IN THE CRUCIFORM GALLERY OF ANGKOR WAT,CAMBODIA

In the cruciform gallery of Angkor Wat in Cambodia, red, orange, white and black pigments were widely painted on the surfaces of pillars, walls and friezes. The application sequence of the pigments is different from area to area. The following substances were confirmed from the pigments: hematite (laterite), minium, calcium oxalate hydrates (whewellite and weddellite), Pb–Cl compounds (cotunnite, laurionite and blixite), calcium phosphates (whitlockite), gypsum, hydrocerussite, calcite, anglesite, lead dioxide, azurite and carbon black. The orange pigment (minium) underlies the red pigment (hematite). The former may have been applied at the time of the foundation (the Angkor Wat style period), and the latter in the Bayon style period or later, but mainly before the early 17th century of the current era.     

Micro‐Raman And Micro‐Stratigraphic Analysis Of The Painting Materials In The Rock‐Hewn Church Of The Forty Martyrs In Şahinefendi,Cappadocia (Turkey)

This paper presents the results of analyses carried out on the paintings on the rock‐hewn walls of the Forty Martyrs church at ?ahinefendi in Cappadocia (a UNESCO World Heritage Site), a central region of Turkey, performed during conservation work from 2007 to 2012. The micro‐samples were investigated by spectroscopic, micro‐stratigraphic and scanning electron microscopy analysis in order to study the painting technique, the materials and the degradation products. The micro‐stratigraphic analysis showed a white, sometimes pinkish, plaster. Micro‐Raman analysis, performed on cross‐sections of the mortars, enabled the detection of calcite, gypsum, anhydrite and calcium oxalate. Scanning electron microscopy and energy‐dispersive spectroscopy revealed a similar composition among all investigated phases, aside from minor differences such as the presence of diatoms in the second and third phases and of biotite, lime lumps and plants fragments in the fourth one. Apart from traditional pigments of medieval wall paintings, micro‐Raman analysis revealed the presence of lead‐based compounds and jarosite.     

降雨时长对土壤结皮发育性能的影响研究

室外土遗址经常因遭遇降雨、水淹等发生结皮,造成土遗址表层性能改变,影响土遗址的进一步保护。以定量纯净黄土在等降雨大小下,通过控制不同降雨时长,试验了不同降雨时长下土壤结皮发育的过程,分别测试了降雨前后的结皮厚度、密度、硬度及孔隙结构。结果表明,在降雨量未达到饱和状态时,随降雨量增大,结皮层的厚度、密度、硬度迅速增大,表皮土壤颗粒被击碎,孔隙迅速减小;在降雨量达到饱和状态时,随降雨量增大,结皮层的厚度、密度、硬度缓慢增大,但表皮土壤裂缝迅速发育,由周围向中心形成同心圆状或辐射状裂隙。研究结论可为室外土遗址的保护提供参考。     

The painting of the Etruscan “Tomba della Quadriga Infernale” (4th century BC), in Sarteano (Siena, Italy): technical features

This work presents the results of an investigation of the painting technique used in the Etruscan tomb “Tomba della Quadriga Infernale”. This tomb was discovered in Sarteano (Siena, Italy) in October 2003 and dated back to the second half of the 4th century BC. Red, dark red, pink, yellow, white, black, and grey colours were used in the tomb in order to create paintings, which now represent a very precious record of the Etruscan art of wall painting in a hypogeal environment. The technical features of the painting were revealed by stratigraphy using optical and electronic microscopy. The components and preparatory layers of the painted areas were characterized using Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray microanalysis (SEM-EDS), X-ray diffraction (XRD), and gas chromatography/mass spectrometry (GC/MS). XRD, SEM-EDS, and optical microscopic techniques were also used for mineralogical analysis of the rock substrate. The SEM-EDS and FTIR analyses showed that red and yellow ochre, calcite, and vegetable charcoal were used to paint the walls of the tomb: the pigments, either alone or mixed together, were utilized to produce pure colours (red, yellow, white, and black) and intermediate tonalities (pink, dark red, and grey). SEM-EDS, FTIR, and XRD highlighted that the painting was made on a preparatory layer of calcite, applied onto a levelling material made up of calcite, clay minerals, quartz, and iron oxides. GC/MS analyses revealed that egg was used as an organic binder to disperse the pigments.     

Damage or protection? The role of smoked crust on sandstones from Yungang Grottoes

Black crusts, such as dust deposit and smoked smudge, are the main pollutants in Yungang Grottoes, the world famous Buddhist heritage site. It is always considered that the black crust should be removed during the conservation process of stones. In this paper, the investigation of the role of smoked crust on the Yungang sandstones was performed to verify if the smoked layer on the stone surface would be harmful or protective. The results of SO₂ corrosion experiments with and without water both show that the samples covered with smoked layer can play a protective role on the sandstones, which means that the smoked layer on the stones can prevent the attack of SO₂ and water, the major deterioration agents in Yungang area. The multi-factor deterioration cycle experiments, including salt crystallization, freeze–thaw damage, wet–dry cycle and acid corrosion, also indicate that the smoked samples are less deteriorated and salt crystallization is the most severe damage to the sandstones.     

Red calcite: an indicator of paleo‐karst systems associated with bauxitic unconformities

A unique red calcite generation, which fills fractures/cavities, is hosted by Mesozoic carbonates in the Transdanubian Range, Hungary. Solid inclusions are located along growth zones of calcite. Hematite, the most abundant solid inclusion, gives the red colour of it. Outcrop‐scale geometry, mineralogical features and detrital mineral assemblage (hematite, gibbsite, goethite, kaolinite, smectite, illite, Cr‐spinel, monazite, xenotime, zircon, apatite and Ti‐oxide) of calcite precipitates suggest strong correlation between the calcite and nearby karst bauxite deposits. Fluid inclusion petrography and microthermometry (T < 50°C; salinity from 0 to 0.17 NaCl eq. w%) of primary fluid inclusions, and the stable isotope trend of the calcite, following the meteoric water line, clearly indicate vadose and phreatic meteoric origin in a near‐surface karst system. The late Cretaceous to mid‐Eocene unconformity‐related cavity‐filling deposits occur close to the surface; indicating that the most recent Quaternary exhumation re‐exposed those surfaces that existed at the time of calcite mineralization. Thus, red calcite precipitates are interpreted as being speleothems, vestiges of the subterranean part of the pre‐Middle Eocene karst. The infiltrated, fine bauxite particles enclosed by the calcite are the witnesses of the once areally extensive pre‐Middle Eocene bauxitic blanket that became partially eroded by the time of the deposition of the cover beds. Red calcite when found in core samples may provide good evidence on bauxite formation associated with the overlying unconformity, even if it was later removed by erosion. Therefore, presence or absence of red calcite may be used as distinguishing criteria between karst episodes with or without bauxite formation.     

传统水硬性灰浆性能的影响因素综述

水硬性灰浆是性能优良的传统建筑材料,其相比于气硬性灰浆,有更好的防水性、透气性、耐冻性、耐盐结晶性和机械强度等,适合作为古建筑的修复材料。本研究对影响传统水硬性灰浆性能的因素进行归纳综述,探讨无机物(胶凝材料、骨料、水)、天然有机物(多糖类、蛋白质类、油脂类)、养护条件等对水硬性灰浆性能的影响。其中,无机物对水硬性灰浆的性能影响一方面取决于胶凝材料的特性,另一方面取决于灰浆中不同无机组分间的比例;在水硬性灰浆中加入多糖类有机物可提高灰浆力学性能,加入蛋白质类有机物可提高防水性和孔隙率,加入油脂类有机物可大幅提升防水性、耐久性;在高相对湿度条件下养护水硬性灰浆可提高其机械强度,而低湿度条件下养护的灰浆则更具耐久性。本研究成果可为认知、揭示传统水硬性灰浆的科学价值,研究、开发新型古建保护修复材料提供参考与启示。     

Catastrophic Limestone Decay at the Central Sanctuary of Iupiter Dolichenus at Dülük Baba Tepesi in Southern Turkey: Causes and Implications for Future Conservation

Dramatic deterioration of Hellenistic-Roman limestone remains recently excavated at Dülük Baba Tepesi (Southern Turkey) has been observed following the cold, wet winter of 2011/2012. A conceptual model is presented to explain the dramatic deterioration in which case hardening develops and initially strengthens the stone against deterioration, but then makes it more prone to exfoliation and blistering. Data collected using non-destructive techniques (Equotip surface hardness tester and Karsten tube for water uptake) on F?rat and Gaziantep formation limestone time series excavated in 2005, 2007, and 2013 demonstrates the progress of case hardening and deterioration after excavation. In combination with meteorological data from Gaziantep weather station the results are used to test and revise the model taking into account non-linear and threshold effects. Future excavation and conservation efforts should take into account the often-complex interactions between post-excavation case hardening and extreme winter conditions which can cause catastrophic deterioration.