Assessment of the Effects of Freeze–Thaw and Salt Crystallization Ageing Tests on Anahita Temple Stone,Kangavar, West of Iran

Building stone of Anahita Temple seriously suffers from weathering due to long term freezing-thawing and salt crystallization processes. This article investigates possible changes of physical and mechanical characteristics of this stone subjected to freeze–thaw and salt crystallization ageing tests. Fresh samples obtained from the Chelmaran quarry (the main quarry supplying for Anahita Temple stone) were tested under freeze–thaw and salt crystallization experiments. The freeze–thaw and sodium sulfate salt crystallization are suggested to be the most effective factors affecting in apparent deterioration of the stone in compare to the magnesium sulfate salt crystallization test. Significant decreases in mechanical properties of the stone were observed after freeze–thaw and salt crystallization tests. However, more mechanical losses were recorded after the salt crystallization cycles than the freeze–thaw cycles. This is probably due to crystallization pressure of salt crystals in compare to ice wedging force, which promoted more development of micro-fractures in the specimens. Probably, intrinsic factors of the stone such as frequent calcite veins and stylolites, are the main factors that control the durability of Anahita Temple stone. Preferential weakening along these features during freeze–thaw and salt crystallization cycles led to physical destruction and strength loss of the stone. Based on comparison between experimentally induced damages and field observations, reasonably freeze–thaw process is major factor in weathering of Anahita Temple stone. It should be noted that recorded 102 frozen days for the region imply high destruction potential of the stone during freeze–thaw cycles.     

南响堂石雕表层的孔隙、粒度变化与环境污染

南响堂石窟石雕表面风化破损现象日趋严重,表现在文物表面粗糙、开裂或完全破损。以石雕表层粒度、孔隙特征为主要研究对象,采用偏光显微镜、电子显微镜、红外光谱及ZHISS图像分析仪等分析方法,对风化壳剖面分层的成分、结构等进行系统研究,总结出各分层孔隙、粒度变化的规律及成因。最终证实环境污染物对该石质文物起到后生改造破坏作用。     

浙江青田石矿物成分和成玉机理研究

采用x射线粉晶衍射、红外吸收光谱、扫描电子显微镜和差热分析等测试方法对浙江青田石进行了研究结果表明，青田石中多数品种属叶蜡石型，新发现有迪开石型、伊利石型和绢云母型等非叶蜡石型品种，并对其宝石学特征和成玉机理进行了初步探讨。     

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.     

Stone line profiles: Importance in geochemical exploration

In vast tropical rain forest areas, weathering profiles are commonly characterized by a “stone line” overlain by a brown-yellow loose-clay horizon. Concordant with the topographic surface, such a stone line may be traced continuously over considerable distances. It is typically composed of coarse fragments of lithorelics, debris of laterite as Fe-oxides nodules, corroded quartz, gibbsitic aggregates, …, embedded in a clayey matrix. These materials cover the saprolitic weathering profile which is typically a few tens of metres thick.The origin of stone lines has given rise to much controversy and are still widely misunderstood. A broad range of processes, allochthonist or autochthonist, have been put forward in the literature. The findings in this paper conclude that these weathering profiles result from chemical leaching and differential movement between the matrix and the coarse fragments which accumulate by downward migration. Accumulation takes place at the lower limit of rain water impregnation and forms the stone line, whereas leaching and homogenization of fine material occur throughout the upper water-impregnated horizon. Although the materials of the loose-clay horizon and of the stone are extensively altered, the relics are chemically rather well recognizable.According to the above hypothesis, stone line weathering profiles should thus be mostly residual. The main aspects of geochemical dispersion processes of some stone line profiles in Gabon are presented as examples. These show that:

1. (a) The vertical redistribution of some major elements in the profiles, accumulation (Fe₂O₃, Al₂O₃, SiO₂) or leaching (K₂O, MgO, CaO, SiO₂,..) are different from the bedrock composition;

2. (b) In some situations, it is possible to characterize the bedrock by using groups of trace elements such as V, Ni,.. for basic rocks or Ba, Sr,.. for gneisses for instance; the contrasts obtained can be smoothed in comparison with results from deeper in the profile.

3. (c) The persistence of geochemical anomalies arising from mineralization, throughout the weathering profile, up to the main sampling media, the surface soil. A “mushroom” dispersion pattern can be recognized where the foot of the mushroom corresponds to the element dispersion pattern can be recognized where the foot of the mushroom corresponds to the element dispersion in the saprolite and the bedrock, with the top of the mushroom being partly in the stone line and partly in the loose clay horizon.

Such a dispersion pattern has two consequences on exploration: (1) the spreading out of the surficial signal favoring the identification of anomalies during follow-up on a relatively wide spaced grid; and (2) at the same time, a reduction of the extension of the signals by dilution and leaching according to the weathering process; therefore, relatively low anomaly contents must be taken into account in exploration.Thus, anomalies arising from stone line profiles tend to be well-dispersed, but of weak magnitude, and represent in situ transfer from the parent rock.     

Nonlinear Behaviour of an Embankment on Floating Stone Columns

This paper describes a benchmark problem for a floating stone columns supported embankment. In the 3D model, a thick soft subsoil deposit represented by Singapore marine clay was treated by floating stone columns to support a 2.0 m high embankment. The 3D numerical results were compared among different constitutive models such as the hardening soil model, soft soil model, modified Cam-clay model and Mohr-Coulomb model, highlighting the effect of non-linearity in the overall performance of the ground structure. The advanced constitutive soil models allow more realistic soil response to be investigated. From the numerical results, the Mohr-Coulomb model with elastic-perfectly plastic stress-strain response was able to give comparable total settlements but failed to demonstrate some intrinsic behaviours obtained with advanced soil models. These intrinsic behaviours include the mode of failure, displacements profile, stress transfer mechanism and rate of consolidation. This benchmark example has given us an improved understanding of the performance of floating stone columns when a more realistic soil behaviour is modelled.     

The soluble organic compounds of the Bells meteorite: Not a unique or unusual composition

The Bells meteorite is a CM2 chondrite that has long been considered anomalous for having mineralogical and isotopic differences with CMs together with an overall affinity to CIs in its matrix. We extracted a fragment of the only Bells stone collected unweathered with water and solvents and studied the meteorite’s soluble organic composition. We found Bells to contain abundant organic compounds, which are predominantly O-containing such as hydroxy- and di-carboxylic acids, and a scarcity of amino acids and other N-containing compounds. Amines were not detected and ammonia is less abundant than in both the Murchison and Ivuna meteorites. Overall, Bells’ soluble organic composition is more similar to that of Ivuna than of Murchison. The observation that Bells’ amino acid suite shares a distinct distribution of characteristic molecular species with other stones that are thought to have experienced extensive parent body aqueous alteration, such as the Orgueil, Ivuna and recently analyzed GRO 95577 CR1 meteorites, seems to allow the suggestion that such a composition is secondary to prolonged aqueous alteration processes that superseded some of the initial compositional distinctions determined by the asteroidal environments.     

Stone preservation with illustrative examples from the United Kingdom

Interest in the preservation of rapidly decaying monuments, especially in urban areas, has increased appreciably over the last three decades. A stone preservative can be defined as a chemical treatment, which, when applied to stone, combats the harmful effects of time and environment, thereby prolonging the life of a stone by either restoring its physical integrity or by inhibiting its decay. Any preservative applied to stone must not change the natural appearance or architectural value of the stone to any appreciable extent. There are two principal means by which stone can be preserved. One involves the formation of an outer stabilized zone around the stone; the other alters the chemical composition of the stone.A number of examples of stone preservation carried out on ancient monuments in the United Kingdom are taken to illustrate stone preservation methods. Their relative success is evaluated, and some more recent developments in stone preservation referred to.     

中国地台区张裂盆地沉积

本文着重讨论中国地台区某些张裂盆地的沉积与演化特征。张裂盆地可分为陆内断陷和裂谷、克拉通边缘裂陷槽和被动大陆边缘。裂谷在发展过程中依次形成玄武岩-红层-蒸发盐组合或玄武岩-红层-煤系组合→深湖相组合→红层组合。中小型断陷的岩石组合类似但多不完整。豫陕裂陷槽的岩石组合为下部硅碎屑岩组合,以钾玄岩系为主体的火山岩组合,上部硅碎屑岩-碳酸盐组合,以及较深水相泥硅质岩组合。地处被动大陆边缘的扬子地台南部早寒武世海是以波浪作用为主的陆架,其东南边缘的石煤可能是远洋、半远洋沉积。本文还扼要讨论了张裂盆地在控制某些矿产资源的形成与分布方面的一些问题。     

微波等离子体炬质谱技术快速鉴别天然石材与人造石材

天然石材主要有大理石、花岗岩等;人造石材多以不饱和聚酯树脂为基料,添加适量的无机物粉料和添加剂固化制成。由于石材种类繁多,并且各种石材的岩体所含矿物成分也有差异,当前很少应用化学成分分析方法准确、快速鉴别天然和人造石材,仅有的红外光谱法由于对待测物纯度的要求较高而具局限性。本文基于微波等离子体炬源(MPT)同时具有热解吸与强电离能力,能在短时间内离子化待测物的特点,采用微波等离子体炬质谱(MPT-MS)技术,无需样品复杂预处理直接对天然与人造石材进行分析,获得正离子检测模式下在m/z 50~1000之间的石材的指纹谱图,并运用化学计量学的主成分分析(PCA)方法处理所获取的数据,实现了不同建筑石材的区分。结果表明,MPT-MS能够获得石材丰富的指纹谱图,结合PCA方法能够快速鉴别天然石材与人造石材,天然石材中解吸出的物质主要为CO₂和H₂O的团簇分子;而人造石材中解吸出的主要成分为有机物(人为添加的黏合剂等)。本研究采用的MPT-MS技术无需采用喷雾、激光、基质和加热等方法辅助,并且无需对石材进行任何复杂的处理即可进行质谱分析,从而获取石材表面及内部物质的质谱信息,为快速直接鉴定石材样品提供了一种新的质谱分析方法。     

湘西地质公园红色碳酸盐岩石林发育特征与研究价值

红色碳酸盐岩石林是湘西地质公园最重要的地质遗迹之一。公园内的红色碳酸盐岩石林发育于奥陶系大湾组与牯牛潭组,集中分布于酉水－猛洞河两岸斜坡与峡谷地带,出露面积84 km2,是当前全球已知的面积最大的奥陶系红色碳酸盐岩石林地貌景观。红石林形态多样、成景效果好,发育了包括塔状、火焰状、墙状、剑状、柱状、锥状等十余种形态。红石林的形成经历了完整的地层沉积-构造抬升-风化剥蚀等阶段,适宜的古地理环境、有利的构造抬升运动和节理裂隙发育、温暖多雨的气候和丰富的地表地下水系是红石林发育的重要条件。因受成景地层的岩性组成复杂、地层偏薄、溶蚀作用差异等因素影响,红石林具有明显的垂直溶痕和水平溶痕叠加现象,具有独特的自然美,形态上与云南石林有较大不同,颜色上,红石林晴红雨黑、四季变幻,可能是石柱表面的藻类造成。除中国西南地区,其他国家或地区的奥陶系红色碳酸盐岩石林分布十分有限,仅泰国沙墩有报道,其稀有性非常突出,具有重要的科学意义和研究价值。但正由于其稀少,许多针对性的研究仍刚起步,值得未来各界学者进一步深入探讨。     

Moisture sorption behaviour of salt mixtures in porous stone

Moisture in stone material is the key factor for all stone deterioration processes and also in weathering of cultural heritage. With additional presence of salts in the material the situation gets even more critical. While the properties of pure salts with moisture are well known, knowledge about the interaction of salt mixtures with moisture is still poor. In different approaches the reactions of salt-contaminated stone material on changing moisture were tested in the laboratory. Experiments with different solutions in the Na-Mg-SO₄-NO₃-H₂O system revealed interesting new results on the moisture behaviour of salt-contaminated samples. Theoretical considerations and computer simulations are helpful to interpret the data obtained, but are not yet sufficient to explain the real processes acting on site at the monuments. More encouraging to this fact are complementary studies on visible efflorescences in the same salt system. It is shown how by experimental approaches the understanding on salt-induced stone deterioration is strongly complemented.     

青田石的矿物组成特征研究

采用偏光薄片观察、X射线粉晶衍射仪、扫描电镜/能谱分析等测试方法对浙江青田县青田石进行了研究,结果表明,所选青田石样品中的封门黄、黄金耀、灯光冻、红花冻4个品种的主要矿物成分为叶蜡石;封门黑、紫檀冻这两个品种主要由叶蜡石和绢云母组成;蓝星、猪油冻、酱油冻这3个品种的主要组成矿物为叶蜡石和伊利石;珍珠冻的主要组成矿物是红柱石和叶蜡石;山炮绿的主要组成矿物为绢云母。     

高密度电法在石材矿探测中的应用

针对石材矿勘探和开发中存在的矿体边界确定、石材完整性判别等实际难题,首次将高密度电法技术引入到石材矿探测中,在新疆哈密黄山南黑冰花型石材矿开展了探测研究。通过改造测线布置方法、优选装置,获取了高分辨率的测量数据;进行二维反演和三维电阻率成像反演,实现了三维电阻率数据体在三维可视化环境下的交互式显示和操作;结合地质资料,完成了对石材矿的探测解释及评价。结果表明:高密度电法能清晰地刻画出具有高电阻率特征的石材矿矿体三维空间形态,对影响石材矿质量的风化层、裂隙构造等不利因素有较强的识别能力。     

Beyond hydrogeologic evidence: challenging the current assumptions about salinity processes in the Corangamite region, Australia

In keeping with the standard scientific methods, investigations of salinity processes focus on the collection and interpretation of contemporary scientific data. However, using multiple lines of evidence from non-hydrogeologic sources such as geomorphic, archaeological and historical records can substantially add value to the scientific investigations. By using such evidence, the validity of the assumptions about salinity processes in Australian landscapes is challenged, especially the assumption that the clearing of native vegetation has resulted in rising saline groundwater in all landscapes. In the Corangamite region of south-west Victoria, salinity has been an episodic feature of the landscapes throughout the Quaternary and was present at the time of the Aboriginal inhabitants and the first pastoral settlement by Europeans. Although surface-water salinity has increased in some waterways and the area of salinised land has expanded in some landscapes, there is no recorded evidence found which supports significant rises in groundwater following widespread land-use change. In many areas, salinity is an inherent component of the region’s landscapes, and sustains world-class environmental assets that require appropriate salinity levels for their ecological health. Managing salinity requires understanding the specific salinity processes in each landscape.     

Moisture content of natural stone: static and dynamic equilibrium with atmospheric humidity

Among hygric properties of stone material, the sorption behaviour is of essential importance because of the permanence of the processes involved. New results from static sorption experiments performed by standard techniques and by a new tool are reported for six different building stones. Furthermore, an example of dynamic sorption behaviour under continuously changing humidity is presented. For the static equilibrium sorption measurements a close relation to the stone type, its pore properties, such as specific inner surface, pore volume, pore size distribution as well as capillary water uptake and water saturation, is drawn. The comparison of the different data allows us to retrieve correlations between material features that are crucial for weathering processes. The sorption–desorption processes respond spontaneously on even small humidity changes as shown by the dynamic sorption experiment. A permanent breathing-process of the material is imposed.     

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.     

Pathogen transport in groundwater systems: contrasts with traditional solute transport

Water quality affects many aspects of water availability, from precluding use to societal perceptions of fit-for-purpose. Pathogen source and transport processes are drivers of water quality because they have been responsible for numerous outbreaks resulting in large economic losses due to illness and, in some cases, loss of life. Outbreaks result from very small exposure (e.g., less than 20 viruses) from very strong sources (e.g., trillions of viruses shed by a single infected individual). Thus, unlike solute contaminants, an acute exposure to a very small amount of contaminated water can cause immediate adverse health effects. Similarly, pathogens are larger than solutes. Thus, interactions with surfaces and settling become important even as processes important for solutes such as diffusion become less important. These differences are articulated in “Colloid Filtration Theory”, a separate branch of pore-scale transport. Consequently, understanding pathogen processes requires changes in how groundwater systems are typically characterized, where the focus is on the leading edges of plumes and preferential flow paths, even if such features move only a very small fraction of the aquifer flow. Moreover, the relatively short survival times of pathogens in the subsurface require greater attention to very fast (<10 year) flow paths. By better understanding the differences between pathogen and solute transport mechanisms discussed here, a more encompassing view of water quality and source water protection is attained. With this more holistic view and theoretical understanding, better evaluations can be made regarding drinking water vulnerability and the relation between groundwater and human health.     

Tropical stone lines and podzolized sand plains as paleoclimatic indicators for weathered cratons

Stone lines and podzolized (white) sand plains are characteristic features of the regolith in many low-latitude cratonic landscapes, but nevertheless often seem to be out of phase with the present pedogenic and geomorphic regimes of the humid tropics and subtropics. Consideration of contemporary environments where the genetic processes related to these features can be observed, implies several conditions for prior events in landscape evolution: (1) tropical stone lines may be interpreted as winnowed mudflows or lag deposits that reflect morphoclimatic events of brief duration (torrential rains) within an arid or semi-arid phase of pronounced global cooling; (2) within the present zone of the prevailing westerlies, stone lines may reflect periglacial activity during brief interstade fluctuations; (3) in lower latitudes the principal stone line, which commonly truncates saprolites, appears to be late Wisconsinan (Würmian) in age coinciding more or less with the pleniglacial phase; (4) the podzolized sands represent leached residuals and, accordingly, reflect extended intervals of leaching during the Pleistocene; and (5) the nature and distribution of podzolized sand plains indicates a pedogenic history of considerable variety and no brief episodicity as implied with stone lines.     

云南多乐原溶洞异位石花的发育特征与机理研究

石花（方解石花、文石花和石膏花）是一种常见的岩溶洞穴次生化学沉积物,广泛分布于洞道周壁,以及石钟乳、石笋、崩塌堆积体表面,其成因不同,形态千差万别。云南多乐原溶洞中若干高悬的次生化学沉积物表面的石花,通过实地考察,发现是一种异位石花。其成因是石柱形成过程中,由滴水和溅水的协同作用所形成,而后石柱底座的古河流堆积体遭到侵蚀搬运,石柱悬空而成新的石钟乳或类石钟乳,附着其底部的石花相对抬高因而显露出来。此类异位石花为云南首次发现,可以作为指示溶洞内微地貌演化的重要依据。