Determination of deterioration of the main facade of the Ferit Paşa Cistern by non-destructive techniques (Konya,Turkey)

Building stones have long been one of the most widely used construction materials in the world. Building stones used in historical monuments are deteriorated partly or completely depending on the environmental and atmospheric effects. In recent years, non-destructive test methods have been used to assess deterioration of building stones used in historical monuments. Gödene stone is one of the building stones being widely used in the historical buildings in the Konya region, Central Anatolia. The most deterioration effects are observed in the Ferit Pa?a Cistern among the historical structures built with Gödene stone in the region. The aim of this study is to assess the deteriorating effects in the street façade of the Ferit Pa?a Cistern via non-destructive testing methods (Schmidt hardness rebound value, P-wave velocity, humidity measurement and thermal imaging) and create maps of deteriorated features. Turkey’s historic places are integrated to Turkish culture, efforts are made to conserve heritage through rehabilitation. Therefore, this study will help developers and federal managers during the project planning stage by providing technical data.     

Heritage stone in South Australia

South Australia has the greatest utilisation of heritage or building stone in Australia because of its lack of timber resources. Consequently, natural stone was intensively used from the beginning of European colonisation. Building stones in South Australia, notable for their variety given the State’s diverse geology, can be challenging to designate as to their international importance. However, dimension stone in South Australia can also be designated as having national, regional, local or prospective importance. Commonly, stone in South Australia is restricted in use to a specific town, or even a single construction, and has only local significance except where use involves special stone characteristics, unusual stone masonry or use in a building with significant heritage. For instance, the town of Second Valley has a localised use of marble, likely the earliest use (1849) of this rock type in the State. Another example, ‘Adelaide Black Granite’, quarried since 1958, should probably be recognised internationally as a ‘Global Heritage Stone Resource’, as it has had intensive monumental use around Australia, utilisation as cladding in modern buildings, as well as paving and walling in Australia’s National Parliament in Canberra. It has also been exported, notably used for the Australian Embassy in Japan and for a major War Memorial at Le Hamel, France. South Australian slate quarries also provide significant heritage stone. For example, the Willunga Slate quarry south of Adelaide has been sourced for roofing slate and walling since 1840 and is arguably the longest continuous mining operation in Australia; this resource has obvious national significance given a period of quarrying extending to the present, coupled with national distribution of its products. Probably the most widespread stone sourced in South Australia is the surface limestone or calcrete, quarried in the Adelaide area until the 1850s and used for general construction. The stone continues to be used in rural areas. While arguably only of local significance, it could be considered to have national importance because of its extensive use in churches, public building, hotels, houses and simple walling across a vast area of South Australia. Additional research is needed to clarify the heritage status of many building stones used in South Australia.     

Patterns of halite (NaCl) crystallisation in building stone conditioned by laboratory heating regimes

The crystallisation of soluble salts within the pores of the stone is widely recognised as a major mechanism causing the deterioration of the stone-built architectural heritage. Temperature, in turn, is one of the main controls on this process, including salt precipitation, the pressure of crystallisation and the thermal expansion of salts. Most laboratory experiments on decay generated by salts are just carried out with convective heating regimes, while in natural environments building stones can undergo radiative and convective heating regimes. The thermal response of stone to these different heating regimes is noticeably different and might influence the crystallisation patterns of a salt within a stone. The aim of this work is to raise awareness on the different patterns of crystallisation of NaCl within a porous stone tested with different heating regimes (convection and radiation) and the implications that this could have on the design of experimental modelling of natural weathering conditions in laboratory simulations. Results show that heating regime affects the sodium chloride distribution within a stone with high percentage of microporosity. In this case, radiation heating facilitates the generation of subefflorescences, while convection heating promotes efflorescences. This has a clear implication both on the stone decay in natural environments and on the methodologies for testing salt decay, as subefflorescences are more destructive than efflorescences. In this sense, the use of convective heating in laboratory experimentation might underestimate the potential damage that sodium chloride may generate. This counsels the use of radiation heating test methods in addition to convection for the laboratory study of salt crystallisation.     

Changing climate, changing process: implications for salt transportation and weathering within building sandstones in the UK

Salt weathering is a crucial process that brings about a change in stone, from the scale of landscapes to stone outcrops and natural building stone façades. It is acknowledged that salt weathering is controlled by fluctuations in temperature and moisture, where repeated oscillations in these parameters can cause re-crystallisation, hydration/de-hydration of salts, bringing about stone surface loss in the form of, for example, granular disaggregation, scaling, and multiple flaking. However, this ‘traditional’ view of how salt weathering proceeds may need to be re-evaluated in the light of current and future climatic trends. Indeed, there is considerable scope for the investigation of consequences of climate change on geomorphological processes in general. Building on contemporary research on the ‘deep wetting’ of natural building stones, it is proposed that (as stone may be wetter for longer), ion diffusion may become a more prominent mechanism for the mixing of molecular constituents, and a shift in focus from physical damage to chemical change is suggested. Data from ion diffusion cell experiments are presented for three different sandstone types, demonstrating that salts may diffuse through porous stone relatively rapidly (in comparison to, for example, dense concrete). Pore water from stones undergoing diffusion experiments was extracted and analysed. Factors controlling ion diffusion relating to ‘time of wetness’ within stones are discussed, (continued saturation, connectivity of pores, mineralogy, behaviour of salts, sedimentary structure), and potential changes in system dynamics as a result of climate change are addressed. System inputs may change in terms of increased moisture input, translating into a greater depth of wetting front. Salts are likely to be ‘stored’ differently in stones, with salt being in solution for longer periods (during prolonged winter wetness). This has myriad implications in terms of the movement of ions by diffusion and the potential for chemical change in the stone (especially in more mobile constituents), leading to a weakening of the stone matrix/grain boundary cementing. The ‘output’ may be mobilisation and precipitation of elements leading to, for example, uneven cementing in the stone. This reduced strength of the stone, or compromised ability of the stone to absorb stress, is likely to make crystallisation a more efficacious mechanism of decay when it does occur. Thus, a delay in the onset of crystallisation while stonework is wet does not preclude exaggerated or accelerated material loss when it finally happens.     

British decorative stones: finding the UK top ten

British geology reveals many good looking rocks, both ‘soft’ and ‘hard’, some of which were once highly prized for their polished decorative uses. They were quarried, cut, shaped and finished in a locally‐based British decorative stone industry that flourished twice, first in the Middle Ages, based largely on Purbeck marble from Dorset and also alabaster from Derbyshire, and then again in the nineteenth century when diverse sources of coloured and textured stone were pursued to the far corners of the British Isles. Today only the finished products survive; the pillars, panels and pavement adorning some fine but dusty architecture, but the stones commonly languish unrecognized and unappreciated. This anonymity is quite out of line with the heritage status of their settings and it will take a bit more geological awareness to put that right. A recent project aimed at rediscovering just one regional category of British decorative stones, the Devonshire marbles, has revealed how diverse and extensively‐used the fuller range of British decorative stones actually is. Not only do they embellish buildings from the merely modest to some of our finest, they were latterly chosen, specified, designed and coordinated by some of our greatest architects. Much work needs to be done to recognize British decorative stones in architectural settings and to restore them to their proper place in our national heritage. It is hoped that this article will throw light on the task ahead.     

Texture Analysis of Grey-Tone Images by Mathematical Morphology: A Nondestructive Tool for the Quantitative Assessment of Stone Decay

Both a low-cost and easily handled nondestructive methodology and its validation criterion are proposed. The methodology is based on image analysis by mathematical morphology for the assessment of decayed stone surfaces in historic limestone buildings. It is adapted to follow the evolution, at macroscopic time and space scales, of stone materials used in art pieces and monument building stones. This methodology is applied to the quantitative analysis of textures of static grey-tone CCD video camera images representative of flat stone structures that cannot be handled. These structures line the walls inside an important church, Basílica da Estrela, built in the 18th century and located in the city of Lisbon. Detailed visual/tactile observation shows that these flat vertical structures are more or less damaged depending on their position inside the church. The damage is possibly associated with different environment conditions both from the atmosphere inside the church and from contact with the walls of the church. The presence of these pathologies breaks down the order and organization of sound rock textures introducing changes in the topographical and optical characteristics of the texture of the surfaces. This new methodology is based on the granulometry and covariance analysis of grey-tone images corresponding to the structures studied. The validation criterion allows the results of the proposed methodology to be compared to the results of a previous qualitative study made by experts in the field using visual assessment and monument mapping as a valid methodology to assess the degree of decay. This procedure is based on optical and topographical characteristics and type of decay of the stone surface, and the quantity of material lost from the surface of the panels during the year. As discussed in this paper, in the context of cultural heritage, the proposed methodology was validated and its results can be considered an improvement on and complementary to expert visual analysis and also to other nondestructive techniques.     

The use of X-ray tomography in the study of water repellents and consolidants

To reduce the weathering rate of natural building stones, a wide variety of water repellents and consolidants are commercially available. Although a lot of research is performed on these products, it remains difficult to determine which product is appropriate to use for a certain type of building stone. Each type of building stone has its own petrographic characteristics (mineralogy, texture, …), leading to typical physical and technical properties which influence its rate of decay. The localisation of the products inside a stone type is not only depending on the properties of the products themselves, but also linked to the texture and structure of the stone. The impregnation depth of the products strongly influences their efficiency and is therefore a key issue in the determination if a product is functional for a certain type of stone. X-ray micro-CT has recently been introduced as a non-destructive material evaluation technique for engineering and geology purposes. The fact that micro-CT can provide information about the internal structure and properties of natural building stones, is a major advantage in the study of their conservation. Firmly linked with more classical research techniques, this non-destructive technique offers an extra dimension to the cultural heritage research.In this paper, non-destructive X-ray computed micro-tomography (micro-CT) turns out to be a powerful tool as it can visualise the presence of water repellents and consolidants inside the stone and can help to detect the influence that these treatments exert on porosity and pore-size distribution. For the visualization of the product its atomic number and density and the amount of product inside the natural building stone is crucial. Besides the contrast in attenuation, the resolution of the micro-CT also needs to be taken into account to obtain a good contrast between stone and product. By doping with 3-bromopropyltrimethoxysilane, more contrast occurs between the stone material and the conservation product. When the amount of product inside the samples is very low and the product is homogeneously spread inside the sample, the doped product is difficult to distinguish from the stone material due to the resolution of the micro-CT. When the amount of doped product inside the stone material reaches a certain threshold value, the dope will appear in the 2D cross-sections derived from micro-CT, creating a good visualization of the products inside the stone samples.     

Environmental impact on the Roman monuments of Tarragona,Spain

The extant remains of the Roman monuments of Tarragona, Spain are made of different types of Miocenic rocks from the quarries surrounding the city, which vary from calcarenite to bioclastic limestones, showing different degrees of dolomitization, depending on their diagenetic evolution. The decay of these monuments is highly dependent on the mineralogy and the fabric of the stone as well as on the environmental conditions to which the monument subjected. As a consequence, different forms of decay are observed on these monuments, namely, granular disintegration, differential erosion between sparitic and micritic areas of the rock, and development of black crust and orange patinas, some of them attributed to a sulfation process. A number of processes have been established as being responsible for the decay forms observed: sulfation on sheltered areas of the building in the urban environment; differential dilatation because of the NaCl of the marine spray that crystallizes inside the porosity; hydric and thermal expansion of the stone, both related to the amount and crystallinity of the clay minerals forming the rock matrix; and biocolonization on the stone surface. An empirical model is proposed to explain the decay forms studied in relation to these factors (rock and environment).     

Durability of carbonate rock as building stone with comments on its preservation

Carbonate rocks have been extensively used as building stones because of their availability, workability, and attractiveness. Unfortunately, however, some stones suffer from chemical attack or freeze-thaw activity. The environmental affects, especially those due to pollution of the atmosphere, are discussed in terms of weathering processes, salt crystallization, and acid deposition. A review of some recent research in relation to deterioration of stone in urban environments is given and carbonate rocks are classified in relation to position within a building, geographical location, and degree of pollution. Some comments on stone preservation are provided, especially in terms of the properties a preservative should possess.     

桂林地质遗迹景观特征及其保护开发策略研究

桂林地质遗迹景观是桂林最为重要的旅游资源。在详细的野外调查基础上,依据地质遗迹调查规范（DZ/T0303-2017）,梳理了桂林6区10县1市共17个区域内的312处地质遗迹景观,划分出3大类,9类和20亚类地质遗迹景观类型;景观具有数量丰富,类型多样,特色突出,品质极高,分布广泛,相对集中,地质旅游价值大等7大特征,采用直接认定法与专家打分法对地质遗迹景观质量进行等级评价,结果显示,桂林有7处世界级景观、32处国家级景观、105处省级景观、168处省级以下景观。桂林地质遗迹景观数量、类型、质量等级在各区域空间分布不均衡。文章提出建立统一的保护体系、统一的管理监督机制、桂林地质遗迹景观法律法规保障体系、桂林地质遗迹景观监测预警系统、加强科普教育,提高公众对地质遗迹景观价值和功能的认识等5大保护策略;以及保护性开发、同类景观有序性开发、特色性开发、多元性开发、不同等级景观分级开发等5大开发策略。     

广东乳源彩石的矿物学特征及颜色成因研究

乳源彩石是具有华丽色彩的一种观赏石.采用偏光显微镜、扫描电子显微镜、电子探针、红外光谱仪以及X射线粉末衍射仪等测试手段对4块乳源彩石标本的显微结构、矿物组成和化学成分等进行测试与分析.结果表明,这些乳源彩石具有变粉砂结构,主要由石英组成（占总体质量分数的90％以上）,含少量云母,其它矿物的质量分数低,是一种浅变质的变石英粉砂岩;另外,4块乳源彩石样品的结晶度指数相近,结晶度指数最高的绿色样品推测是由于其含有后期充填的鲕状矿物导致.最后对乳源彩石样品的颜色成因进行了分析与探讨,认为其颜色为次生色,是由次生矿物组合、交代蚀变和氧化程度的不同而形成的.     

Devonshire marbles—the greatest British decorative stones?

‘Devonshire marbles’ were once the pre‐eminent British decorative stones, installed in dozens of Victorian buildings in Britain and elsewhere. There are numerous varieties, none of which are true marbles for they retain the fossils and sedimentary textures of the original Devonian limestones. Quarried and manufactured across south Devon and used both internally and externally, the stones were part of a passing nineteenth century architectural fashion. There are 20 or so main varieties, mostly now unobtainable, but excellent examples are found in the panels, shafts and floors of some exceptionally fine buildings. These reveal much about the fossils, their depositional environments and the changes that affected them during the Variscan orogeny. Now rediscovered and distinguished for the first time using geological criteria, Devonshire marbles represent a valuable resource for geological, conservation, heritage and architectural research.     

Promoting geological heritage through postage stamps

Postage stamps are useful in promoting geological heritage. This concept is explored through an analysis of British and New Zealand stamps, which portray a variety of different types of geological heritage. Coastal, glacial, fluvial and limestone scenery all feature, together with volcanic landforms such as the Giant's Causeway. Other stamps celebrate the work of historically significant figures who have contributed to geology, such as Charles Darwin. The field of palaeontology is represented in stamps, for example, featuring dinosaurs. Others portray economic activities and engineering achievements associated with geology such as oil and gas exploration. Industrial heritage is depicted by stamps featuring, for example, abandoned tin mines, while building stones are represented in stamps of ancient monuments, bridges, cathedrals and domestic architecture. Perhaps subjects for future stamp issues in the UK might draw upon the recently published 100 top geosites list.     

Quality assessment of replacement stones for the Cologne Cathedral: mineralogical and petrophysical requirements

Owing to its long building history, different types of building stones comprised the construction of the Cologne Cathedral. Severe damage is observed on the different stones, e.g., sandstones, carbonate, and volcanic rocks, especially when the different stone materials neighbor the medieval “Drachenfels trachyte” from the “Siebengebirge”. The question arises, “Is the insufficient compatibility of the implemented building materials causatively related to the strong decay of the Drachenfels trachyte?” The present investigations focus on the petrography and mineralogical composition of eight different stones from the Cologne Cathedral. Petrophysical data, i.e., phase content, moisture and thermal characteristics as well as strength properties are determined and discussed in correlation to each other, showing that not only in terms of lithology great differences exist, but also the petrophysical properties strongly diverge. The ascertained parameters are discussed in view of the deterioration behavior and decay mechanisms of the different stones. To evaluate the compatibility of original, replacement and modern building materials, the properties of the investigated stones are compared to those of Drachenfels trachyte by means of constraints given in the literature. Besides optical properties, petrophysical criteria are also defined as well as strength values. It could be shown that primarily moisture properties, i.e., capillary and sorptive water uptake, water saturation, drying processes and moisture dilatation can be addressed to the deterioration processes.     

基于地质建造和流域地貌的河北省承德蟠龙湖地区大比例尺地质遗迹调查

基于地质建造分区和流域地貌演化理论，利用地质建造分析、DEM数字地貌、遥感解译、无人机和野外路线调查等技术方法组合，快速查明了承德蟠龙湖景区地质遗迹单体63处，丰富了景区的地质旅游资源，提升了景区的科学内涵。地质建造决定基础地质大类地质遗迹的内在“基因”，是地貌景观大类地质遗迹形成的物质基础，并通过岩性和构造影响地质灾害大类地质遗迹的发育。流域地貌演化影响基础地质大类地质遗迹的出露情况；是塑造地貌景观大类地质遗迹形成的主要地质营力，影响地质灾害大类地质遗迹发育。将地质建造和流域地貌相结合的思路贯穿整个地质遗迹调查全过程，初步形成“圈定潜力区—摸清家底—探究规律—总结方法”的大比例尺地质遗迹调查技术方法流程。大比例尺地质遗迹调查的目标是力求打通地质遗迹调查与地方需求、旅游产业发展的“最后一公里”，为地质遗迹保护与开发利用、美丽乡村与特色小镇建设提供科技支撑。     

A commentary on climate change, stone decay dynamics and the ‘greening’ of natural stone buildings: new perspectives on ‘deep wetting’

Environmental controls on stone decay processes are rapidly changing as a result of changing climate. UKCP09 projections for the 2020s (2010–2039) indicate that over much of the UK seasonality of precipitation will increase. Summer dryness and winter wetness are both set to increase, the latter linked to projected precipitation increases in autumn and spring months. If so, this could increase the time that stone structures remain wet and possibly the depth of moisture penetration, and it appears that building stone in Northern Ireland has already responded through an increased incidence of algal ‘greening’. This paper highlights the need for understanding the effects of climate change through a series of studies of largely sandstone structures. Current and projected climatic trends are therefore considered to have aesthetic, physical and chemical implications that are not currently built into our models of sandstone decay, especially with respect to the role played by deep-seated wetness on sandstone deterioration and decay progression and the feedbacks associated with, for example surface algal growth. In particular, it is proposed that algal biofilms will aid moisture retention and further facilitate moisture and dissolved salt penetration to depth. Thus, whilst the outer surface of stone may continue to experience frequent wetting and drying associated with individual precipitation events, the latter is less likely to be complete, and the interiors of building blocks may only experience wetting/drying in response to seasonal cycling. A possible consequence of deeper salt penetration could be a delay in the onset of surface deterioration, but more rapid and effective retreat once it commences as decay mechanisms ‘tap into a reservoir of deep salt’.     

Testing of Sydney dimension sandstone for use in the conservation of heritage buildings

This paper deals with the scientific assessment of the physical properties of sandstone used in the conservation of Sydney's historic heritage sandstone buildings. The local Hawkesbury Sandstone has been widely used for all manner of constructions since the early days of the first settlement. In the nineteenth century, dimension sandstone quarries existed all over the Sydney region, and the demand for the stone was great. During this time, a true ‘freestone’ known as ‘yellow block’ sandstone, in which bedding planes were absent, was quarried extensively. This sandstone is also known as a ‘self-colouring’ sandstone, where the rock, although grey when quarried, turns a yellow–brown after a few months exposure to the atmosphere. It can be easily carved and was eminently suitable for the ornate Victorian architecture of the time. There are very few quarries within the Sydney region today capable of producing ‘yellow block’ sandstone. Whenever possible, sandstone from suitable building excavations, particularly on the Pyrmont Peninsula, is used for this work. Conservation work is extremely expensive and the building elements that most need replacement, the overhanging and decorative elements, are usually those that cost the most. It is essential that the most durable replacement stone be selected. Thus, a strict regime of scientific testing is used for any major conservation project, in order to determine the physical properties of possible replacement stone. This is the province of the geologist and involves visual observation in the quarry or excavation, which is a simple, cost-effective means of weeding out poor quality stones, followed by laboratory engineering tests to establish the physical parameters of a sandstone and finally, petrographic analysis. The results of such tests, combined with careful sampling, ensure the best possible quality of replacement material.     

Application of protective products to “Noto” calcarenite (south-eastern Sicily): a case study for the conservation of stone materials

Noto is an important Baroque urban center in south-eastern Sicily, which was completely reconstructed after the severe earthquake of 1693. Most of its monuments and historic buildings were built in Pietra di Noto stone, a pale cream calcarenite, quarried in outcrops located near the city. This stone, still currently used as building material, is undergoing many forms of alteration and degradation, which cause significant damage to monuments. In this study, three commercial protective products were tested on some Noto calcarenite samples from quarries, with the aim of assessing their protective effectiveness. In particular, petrographic analyses by optical microscopy were carried out for textural characterization of the stone materials. Capillary water absorption, porosimetric and colorimetric procedures, UV radiation and salt crystallization aging tests were performed to better evaluate interactions between protective products and substrate.     

景纹石的地质特征及合理开发利用

景纹石属于卵石类,它是一种具有色泽鲜艳、图案各异的观赏石类型,是在特定的地质环境条件下产生的.景纹石分布于安徽省皖南山区的宣州、宁国及泾县一带,它已在我国观赏石中中占有一席之地.本文在进行调查研究的基础上,论述了景纹石的分布特征、产出的地质环境条件,并对景纹石的石质特征及观赏性进行了分析研究,在此基础上提出了景纹石合理开发利用及保护的基本思路,这对我省观赏石资源的开发利用及研究提供了借鉴,并具有较好的社会效益及经济效益.     

Zur Geologie und Petrologie der Inseln Nisyros und Jali (Dodekanes)

Nisyros as well as the islet of Yiali are found in the crossing of two fault lines, that of Episcopi — Patmos and the one of southern Aegean (Soussaki-Gulf of Saronic — Milos — Santorini — Dodecanese) it consists almost exclusively of volcanic rocks, that is lavas and tuff and very limited appearence of Holocene formations. The presence of two volcanic effusions is certified, everyone of which began from basic magma, poor in SiO₂ (olivinic pyroxenic andesites), and gave as final products acidic petrological types (liparites and volcanic glasses). The basic magmas of the first volcanic periods are found only in few places and in very limited areas of appearence. After the ascension of volcanic fragmental products the cycle of the first volcanic period closed with the creation of very thick beds of pumice. The second volcanic period gave more petrological types with transitive forms. After the creation of olivinic — pyroxenic andesites followed the exit of trachyandesites, trachytic and dacitic lavas with final creation of rhyolite and of volcanic glasses. The extension of the mentioned rocks is noted in detail on the geological map. The classification of the exact geological age is difficult because there is no place where they come in contact with sediments. In general the researches think that the volcanity in the region of Dodecanese began during the middle or the end of the Miocene with successive explosions up to the young geological ages. Only on the islet Yiali which consists exclusively of acid lavas (pumice stones, rhyolite, perlite) fossiliferous layers of marly limestone, sandstone and konglomerate are found, as much at the sea level as in the top of the layers of pumice stone, of tyrrhenian age. The discovery of tools of obsidian in the layers of pumice stone is perhaps a sign that these explosions continued up to the Holocene period. Among the post volcanic phenomena are classified emanations, sulfur-genetic activity with the creation of sulfur deposits of the island and the presence of the thermal healing springs in many parts. Petrochemically the lavas of the island Nisyros and Yiali belong to calcium alkaline magmas.