Diagnosis of weathering damage on rock-cut monuments in Petra, Jordan

Studies of many years—combining in situ investigation and laboratory analysis—have provided comprehensive information on weathering damage on the rock-cut monuments in the ancient city of Petra in Jordan. These rock-cut monuments represent outstanding world heritage. Many hundred monuments were carved by the Nabataeans from bedrock about 2000 years ago. The awareness of increasing weathering damage on the monuments has resulted in international efforts towards their preservation. The damage diagnosis has addressed the complex mutual relationships between stone types, stone properties, monument exposure regimes, environmental influences, weathering phenomena, development and extent of weathering damage and weathering progression. The rocks were classified lithostratigraphically and petrographically. Results on weathering forms, weathering profiles and weathering products obtained from monument mapping, in situ measurements and laboratory studies revealed a complex diversity of weathering phemomena with respect to type and intensity. Damage categories and damage indices were used to create a reproducible quantitative rating of weathering damage. Detailed results on weathering forms allowed the characterization and quantification of weathering progression including weathering prognoses. Stone properties and states of weathering damage were jointly considered for the rating of the rocks’ susceptibility to weathering. The systematic evaluation of weathering damage and monument exposure regimes can enhance the assessment of weathering factors and processes.     

Research on limestone decay in a polluting environment, I˙stanbul-Turkey

 I˙stanbul, the capital of the east Roman, Byzantine and Ottoman Empires embraces two continents, one arm reaching out to Asia, the other to Europe. It is therefore, a rich city in terms of monuments and historical cites. Shell limestones of Upper Miocene age are used as building stone in the majority of the monuments in I˙stanbul because of their attractiveness, availability and workability. The durability characteristics of the limestones are examined, and those factors that are responsible for atmospheric weathering are discussed, in a humid and marine environment with important problems of urban pollution, specifically due to traffic. In the present study weathering of the building stones were first examined in situ by macroscopic observations. The weathering that developed as a result of environmental effects since this limestone was first used in historical monuments has been affected 0.1–1.5 cm deep from the surface. The weathered facing stone of Şehzade Mehmed Mosque in I˙stanbul is undergoing a program of progressive replacement. During this study, samples were taken from this monument where the shell limestone was used. The stone surface was principally examined by means of Scanning Electron Microscopy (SEM). Petrographical and mineralogical analyses were made by using optical microscopy and X-ray diffraction method. The physico-chemical properties of these rocks control their weathering behaviour and reactivity. Major and trace element analyses and the effect of deterioration on the physical properties of the limestones (unit weight, porosity and water absorption) have also been investigated. Studies on the samples implies that weathering on the stone surface caused important variations on the physical characteristics of the rock. Received: 11 February 1998 · Accepted: 18 August 1998     

Geoenvironmental studies on conservation of archaeological sites at Siwa oasis, Egypt

Siwa oasis is located in the extreme western part of the Egyptian western desert. There are several archaeological sites in the oasis; the most distinct ones are Alexander the Great temple at Aghormi hill and the Gebel El Mota tomb excavations. They have suffered due to deterioration and cracks of different kinds and some parts are getting worse as rock falls occur. From field inspection and lab analysis, it is clear that lithology plays an important role on the extent of damage. Alexander the Great temple was built over the northern edge of Aghormi hill, which consists of two distinct beds—an upper limestone bed and a lower shale one. From field survey and laboratory analysis, the shale is considered as a high expanded bed and weak in its bearing capacity, as its clay content (mainly smectite) experienced swelling due to wetting from the ground water spring underneath. Consequently, the upper limestone bed suffered from map cracking associated with rock falls due to the differential settlement of the swelled lower shale one. The temple was threatened by slope instability and had experienced many cracks. At Gabal El Mota tomb excavations, it was noticed that a comparison of tombs of the same opening size revealed that those that excavated on shale beds had cracked much more than those that excavated on limestone. This may be attributed to the low bearing capacity of excavated shale walls. The remedial measures suggested to overcome the stability problems on these archaeological sites are grouting or construction of retaining walls.     

The influence of binder/aggregate ratio on the pore properties and strength of repair mortars

Repair mortars with different B/Ag (binder/aggregate) ratios and natural stone were studied in order to understand the influence of limestone aggregate on the properties of mortar and to check the compatibility of repair mortar with a porous limestone. Three different types of mortars with three different aggregate contents were evaluated by using mercury intrusion porosimetry (MIP) and water saturation method (WSM). Changes in density and uniaxial compressive strength as a function of aggregate content were also recorded. For comparison the properties of the porous limestone were also tested, since it is used in monuments and also as aggregate in the mortar. Tested mortars had average porosities of 27.0 % (±2.0), while oolitic limestone has higher average porosity of 32.2 % (±1.9). The limestone has mainly medium and large pore radii (1–100 μm) while the repair mortars even with high aggregate content has predominantly smaller pores. All but one pure repair mortars have higher uniaxial compressive strength than that of the oolitic limestone. The strength decreases while porosity increases with increasing aggregate content.     

Algal and fungal diversity on various dimension stone substrata in the Saale/Unstrut region

Physical, chemical and biogenic weathering considerably threatens all historic stone monuments. Microorganisms, though inconspicuous, are key players of stone surface colonization and penetration. This study highlights eukaryotic microbial communities on dimension stone surfaces from two representative monuments of the “cultural landscape corridor” in the Saale–Unstrut area. The historical buildings were erected from local Triassic limestone and sandstone and are prone to various deteriorative mechanisms. Generally, trebouxiophyceaen algae and ascomycete fungi dominate among the latter dematiaceous fungi and lichen fungi are abundant. Inside the stone substratum, ascomycetes, mosses and even large soil organisms (tardigrades) are present. This may be taken as a hint for the formation of pores with large radii, which are “risk indicators” for progressive weathering and degradation of the rock matrix.     

Acidity gradients in the kipda region

Acid precipitation leaves fingerprints upon marble surfaces. Preserved in weathering crusts on dated monuments, these fingerprints serve as guides to identify levels of acidity of a region. We collected scrapings from protected surfaces of tombstones made of Georgia marble whose dates of installation could be determined with reasonable certainty. These scrapings were allowed to equilibrate in 100 ml of deionized water, and the solutions were analyzed for, among other species, sulfates and nitrates. In Louisville, it was found that sulfate is present on tombstones that had been installed as late as 1985. However, to the east, 25 miles away, 1967 is the date of the latest monument with sulfate. An acidity map was produced showing time contours, in other words, the time needed to produce discernible quantities of sulfate. This map reveals that the effect of SO₂ on marble diminishes rapidly with increased distance away from the western Louisville industrial area. The use of marble monuments to monitor changes in the acid deposition patterns is suggested.     

周口店黄院东山梁构造变形特征及其地质意义

针对周口店黄院东山梁一带青白口系和下古生界构造变形进行的详细解剖分析一直未见有文献报道。通过对东山梁构造变形现象进行反复多次的详细观察,发现东山梁中段寒武系张夏组鲕粒灰岩层位重复出现,但鲕粒未发生变形,经追索表明该层位存在逆冲断层重复和破坏;同时,东山梁南段采石场掌子面可见青白口系景儿峪组薄层大理岩和寒武系府君山组灰岩构成的小型斜歪倾伏褶皱,上覆寒武系馒毛组中发育由NNE向SSW推覆的逆冲褶断,使部分层位缺失,褶断带内岩石存在韧性变形等构造现象。这一观测成果修正了前人研究认为东山梁一带只存在大量折叠层、而断层发育欠佳的认识,也为北京西山地区区域地质演化研究提供了一定的科学佐证。     

藏北羌塘盆地羌资2井中侏罗统布曲组碳酸盐岩岩石学及储集物性特征

本文讨论了羌塘盆地羌资2井中侏罗统布曲组碳酸盐岩岩石学及储集物性特征。碳酸盐岩主要有亮晶鲕粒灰岩、白云岩、泥晶灰岩, 以及他们之间的过渡类型; 储集空间主要有孔隙与裂缝两种类型, 表现为孔隙—裂缝组合。孔隙可分为粒间溶孔、粒内溶孔、晶间孔、晶间溶孔、沿缝合线等分布的溶孔; 裂缝可 分为构造缝、构造—溶解缝、压溶缝和溶蚀缝。亮晶鲕粒灰岩孔隙度平均值1.084%, 渗透率平均值0.0319× 10-3 mm2; 白云岩孔隙度平均值1.77%, 渗透率平均值0.1591×10-3 mm2; 储集物性特征均为低孔低渗、高排替压力、微-细喉道、分选中等-不好的负偏态细歪度特征。泥晶灰岩和过渡类型灰岩的储集物性特征与亮晶鲕粒灰岩和白云岩相似。最后, 讨论了成岩作用对碳酸盐岩储集物性的影响, 并认为成岩作用对储集物性的不利影响明显大于有利影响。     

不同风化程度下灰岩抗剪强度特性及估算模型研究

工程上常见的灰岩在不同风化程度下的抗剪强度特性鲜有研究,也没有快速评估灰岩抗剪强度的数学模型,不能满足大量灰岩工程灾害防治的需要。为探究风化程度对灰岩抗剪强度特性的影响规律,试验选取现场新鲜灰岩试样,通过开展室内风化模拟试验制备不同风化程度的岩样,进行室内岩石强度剪切试验,探究灰岩剪切应力-剪切位移关系曲线的变化规律和...     

A methodology for locating the original quarries used for constructing historical buildings: application to Málaga Cathedral, Spain

It is often necessary to locate the original quarry which supplied the stone for a particular historical building. This stones could be used for future restoration work and for testing in the laboratory (artificial aging tests, physical properties determination, control of the efficacy of conservation treatments, etc.). Generally, reviewing historical documentation gives information about the geographical setting of quarries and location of the stones in the monument, but this information needs to be proved by field and laboratory studies. The comparative study of stone from quarries and monuments should basically include the following: (1) mineralogical and petrographical studies; (2) the chemical analysis of major, minor and trace elements; (3)stable isotopes determinations; (4) physical properties of quarry materials and unweathered building stone (water absorption, ultrasound transmission velocity, porosity and porous system, density, bulk density, compressive strength, etc.). This methodology was applied to Málaga Cathedral stones represented in the main façade, towers, and the western zone of the terrace, which, according to historical literature, came from Almayate (Miocene–Pliocene limestones) and Cerro Coronado (Permotriassic sandstone) in Málaga. The conclusion of the comparative study carried out on quarries and building stones was consistent with the information available from the historical documentation.     

洛阳龙门地区中寒武统张夏组下部遗迹组构及其沉积环境

洛阳龙门地区中寒武统张夏组为一套富含生物扰动的薄层微晶灰岩和厚层鲕粒灰岩沉积,根据沉积学和遗迹学特征,从中识别出6个遗迹组构,从下到上依次是:潮下低能碳酸盐岩台地中的Planolites montanus遗迹组构,潮下浅水较高能碳酸盐岩台地中的Palaeophycus tubularis-Thalassinoides horizontalis遗迹组构,高、低能交替的滨岸浅滩或开阔台地滩间坪或滩前沉积中的Skolithos linearis-Planolites montanus遗迹组构,深水低能开阔台地沉积中的模糊生物扰动遗迹组构,高能鲕粒浅滩中的Macaronichnus segregatis遗迹组构和潮下低能局限台地环境中的Palaeophycus heberti遗迹组构.龙门地区张夏组由无鲕粒滩的碳酸盐岩台地逐渐向发育厚层鲕粒滩的碳酸盐岩台地演化,沉积环境从滨岸浅滩逐渐演变为无鲕粒滩的开阔台地,并随着海退由深水、开阔台地逐渐变浅形成鲕粒滩、局限台地.      

Microbial growth and air pollutants in the corrosion of carbonate building stone: results of laboratory and outdoor experimental tests

The combined effect of microbial colonization by fungal growth and atmospheric pollutants in the sulfation of carbonate rocks was investigated by means of laboratory experiments of dry deposition of sulfur and nitrogen dioxides, in vitro microbiological assays and outdoor exposure tests. All the experiments were performed on Scaglia limestone, which is a very common building material in ancient monuments in Central Italy. Results point to a combined action of particulate matter deposition and sulfation in the formation of gypsum on the samples exposed outdoor, and to a significant influence of fungal growth in the conversion of metal sulfide particulate matter to sulfate thus promoting subsequent formation of gypsum also in the absence of pollution. The chemical and textural features of stone tend to enhance chemical weathering and fungal colonization in the short term, and to preserve the material in the long term.     

Weathering of the black limestone of historical monuments (Ljubljana,Slovenia): Oxygen and sulfur isotope composition of sulfate salts

The black limestone widely used in Slovenian monuments, particularly in the baroque architecture, is deteriorating extensively due to salt crystallization. Samples of soluble salts from two important historical monuments (in Ljubljana, Slovenia) were investigated in terms of their mineral and isotopic (S and O) compositions. Results revealed the presence of gypsum and soluble salts of the MgSO₄·nH₂O series, such as starkeyite (MgSO₄·4H₂O), pentahydrite (MgSO₄·5H₂O) and hexahydrite (MgSO₄·6H₂O). Whereas black crusts and subflorescences consisted of gypsum, efflorescences appeared to be an assemblage of gypsum and MgSO₄ hydrates. Sample δ¹⁸O_sulfate values varied from ?1.9‰ to +5.5‰ vs. V-SMOW and δ³⁴S_sulfate values from ?19.8‰ to +3.2‰ vs. V-CDT. The respective isotopic composition of analysed outdoor and indoor monument samples indicated different sources of contamination.     

鲕粒灰岩的溶解动力学特征和微观形貌的发育演化

鲕粒灰岩是重要的碳酸盐岩油气储层。通过常温常压下,北京西山鲕粒灰岩的溶解动力学实验发现,鲕粒灰岩的溶解主要受岩石和矿物的结构和化学成分控制。结构上表现为构造裂缝、鲕粒结合纹、颗粒晶体结合带等结构薄弱带优先发生溶蚀。成分上表现为白云岩化组分不仅自身较易溶蚀,而且能促进鲕粒灰岩的整体溶解;粘土矿物、石英等杂质组分常与鲕粒和白云岩化颗粒伴生,其对两者的阻溶效应更大。溶解过程中,鲕粒灰岩的构造裂隙、鲕粒放射结合纹和同心圈层等首先发生溶蚀,产生溶隙、粒内溶孔和粒间溶孔;其次为白云质组分以及白云质组分与方解石结合处而产生晶间溶孔、粒内溶孔;随着溶蚀强度的加强,围绕鲕粒形成环状溶蚀沟,在鲕粒溶蚀脱落后而形成鲕模孔。     

西藏改则地区上三叠统日干配错组鲕粒滩相灰岩沉积特征及其环境意义

西藏改则地区上三叠统日干配错组发育了一套台地相碳酸盐岩沉积,在该套碳酸盐岩沉积中以存在大量鲕粒滩为特色。鲕粒滩可以进一步划分为开阔台地浅滩和台地边缘滩。鲕粒滩岩石类型分析表明,该套碳酸盐岩为镶边台地型沉积,开阔台地内浅滩为异地鲕和原地鲕混杂堆积,台缘浅滩鲕粒主要为原地鲕。台缘鲕粒滩为一个三级海侵体系域内部的次一级进积序列,具有潮下型米级旋回的特点,每层鲕粒滩相鲕粒灰岩的类型较为单一,大小均匀,各层鲕粒灰岩间鲕粒类型不同,具有从微晶鲕→放射鲕→同心鲕过渡的趋势,向上鲕粒粒径变大,沉积厚度明显增加。     

Hydrogeological and mineralogical analysis of the pre‐Romanesque monument of Santa María del Naranco,Asturias, Spain

The church of Santa María del Naranco is an important monument from the pre‐Romanesque period of Asturian art. Here we present research that locates the probable source of travertine used in the construction of a vault within this monument. Since the genesis of this travertine is associated with spring activity, and archival evidence suggests that stone procurement during this period tended to be local, we surveyed existing carbonated aquifers within a 5‐km radius of the monument. We identified a spring (Sopeña) with an associated outcrop of discontinuous travertine that appeared to have been quarried in the past. We conducted X‐ray powder diffraction, electron microprobe, and inductively coupled plasma mass spectrometry analyses of samples extracted from the suspected travertine source, an additional more distant travertine quarry for comparison, and the vault. Matching mineralogy and geochemistry indicate that the Sopeña travertine was the probable source of rock material used in the construction of the vault. This study provides insight into local ancient monument construction and can assist in procuring original stone material for historical restoration. © 2010 Wiley Periodicals, Inc.     

Influences of human activity on deformations of the ancient structures of Ichan-Kala in Khiva City

Like Bukhara and Samarkand, Khiva is one of the ancient cities of the world. After Khiva's 2500th anniversary in 1997 UNESCO added Khiva to the list of cities of world heritage. The architectural complex of monuments of Ichan-Kala is the work of ancient Horezm's XVIII–XIX century architects and consists of several structures such as the madrasahs: Alla-Kuli Khan (1835), Tash-Hauli (1832), Amir-Tura (1870), Muhammad-Amin Khan (1871), ancient masonry city wall (1780) and others. Unfortunately, in the course of time, it is inevitable that the monuments accumulate damage. The ancient monuments are less protected against the negative factors of environmental and human activities. With the purpose to find the reasons for the deformation of foundations of buildings of the monument of Ichan-Kala and for the development of techniques for improving the properties of soils, hydro-geological, engineering-geological and geophysical investigations were conducted. This revised version was published online in July 2006 with corrections to the Cover Date.     

Distribution patterns and controlling factors for reservoir characteristic difference of oolitic shoals,Feixian’guan Formation,eastern Longgang area,SW China

In eastern Longgang area of northeastern Sichuan Basin, the Kaijiang-Liangping trough was deposited with and leveled up by Feixian’guan sediments, where oolitic shoals exhibit progradation and upward migration. These oolitic shoals are classified into oolitic dolostone shoals and oolitic limestone shoals. The dolostone shoals occur within a narrow belt along Changxingian platform margin where the thickness of one single layer can be large; however, the cumulative thickness is rather small. On the contrary, the limestone shoals spread widely along shifted platform margin and is characterized by small thickness of one single layer and large cumulative thickness. Diagenesis has been found to play an important role in oolitic reservoir properties. The origin of low porosity and permeability in this extensive oolitic limestone reservoirs was attributed to burial cementation, while diagenetic processes, such as, reflux and hydrothermal dolomitization, have been identified as the primary factors for generating high-grade oolitic dolostones. Feixian’guan reservoir is characterized by low matrix porosity (which usually ranges from 2 to 3%). Existence of fractures may improve overall porosity and permeability of these reservoirs. The direct influence of these fractures may be to connect originally isolated pores to form a better connected pore-fracture system. Additionally, the fractures may have facilitated the migration of the organic acids that are associated with oil and gas, to help further enhance the quality of the reservoir through corrosion.     

Influence of pore system characteristics on limestone vulnerability: a laboratory study

Hyblean limestone of Oligo-Miocene age was widely used as a construction material in the architectural heritage of Eastern Sicily (Italy). Among them, the so-called Pietra Bianca di Melilli (Melilli limestone) and Calcare di Siracusa (Syracuse limestone) were prized for their attractive appearance, ease of quarrying, and workability. Syracuse limestone shows general weathering, whereas Melilli limestone is better preserved, and only differential erosion or superficial exfoliation can be detected in monuments. The cause of the different behavior of these two limestones was investigated from the petrographic and petrophysical points of view. The saturation coefficient is higher in Melilli limestone, and ultrasound measurements indicate that it is less compact than Syracuse limestone, so that Melilli limestone could deteriorate more easily than Syracuse limestone. However, pore interconnections and the size of very small pores play the main role in the durability of both materials. The “irregularity” of the Syracuse pore system and its greater number of micropores hinder water flow through the exterior, promote stress in pore structure, and favor the development of scaling, as confirmed by salt crystallization tests. In Melilli limestone, the low concentration of micropores and fast water evaporation allow solutions to reach the surface more easily, resulting in less damaging efflorescence.     

Time-dependent changes in the strength of repair mortar used in the loss compensation of stone

Repair mortar and mixture of repair mortar with porous limestone sand aggregate were tested under laboratory conditions. Water absorption properties and micro-fabric analyses with a combination of strength tests were applied to assess the durability and compatibility of repair mortar with porous limestone. Uniaxial compressive strength and flexural strength were measured after 3, 7, 14, 28 and 90 days of casting. Durability was tested by comparing strength test results of samples kept air dry, water saturated, dried in drying chamber, freeze–thaw and non-standardized freeze–thaw cycles. The results indicate that with time various trends in strength were observed. In general, limestone aggregate content decreases more the compressive strength more than the flexural strength of the mortar. Standardized freeze–thaw tests of saturated samples caused a rapid material loss after 25 cycles, while freeze–thaw tests of undersaturated samples demonstrated that even after 100 cycles the test specimens still have a significant strength. Water-saturated samples that contain 50% of limestone aggregate have a 50% loss of strength in comparison with saturated repair mortar, while air-dry and water-saturated repair mortar has a minor strength difference after 90 days. The use of smaller amounts of porous limestone aggregate in repair mortar allow the preparation of repairs that are compatible with the monuments of Central Europe that were constructed from porous limestone.