METHODOLOGICAL DEVELOPMENTS IN THE LUMINESCENCE DATING OF BRICK FROM ENGLISH LATE‐MEDIEVAL AND POST‐MEDIEVAL BUILDINGS*

Fired clay brick samples, obtained from a group of seven high‐status late‐medieval and post‐medieval buildings in England ranging in age from c. ad 1390 to 1740, were dated by the luminescence method using an optically stimulated luminescence (OSL) technique. The results obtained indicate that, when applied to quartz extracted from brick, the technique is capable of producing dates that are in consistently good agreement with independent dating evidence for the buildings. For six samples taken from a group of four dating ‘control’ buildings the mean difference between the central values of luminescence and assigned ages was 5 ± 10 years (SD, n = 6). The methodology used is appropriate for application to other standing buildings in other temporal and geographic regions, and may be used with confidence where conventional dating methods are less certain. The study also examines the luminescence characteristics of quartz and the characteristics of the lithogenic radionuclides in brick samples and identifies various aspects related to the assessment of experimental uncertainty in testing the reliability of the method.     

THE DETERMINATION OF BRICK PROVENANCE AND TECHNOLOGY USING ANALYTICAL TECHNIQUES FROM THE PHYSICAL SCIENCES*†

This work applies established analytical techniques from the physical sciences to Irish brick, in order to gather evidence of ceramic technologies, provenance and sources of raw materials. Petrographic microscopy, X‐ray diffractometry and scanning electron microscopy with an energy‐dispersive X‐ray diffraction attachment were used to study the brick of Rathfarham Castle, Dublin, built c. 1618, where clay brick was introduced in 1771. Local clay was fired in the laboratory and analysed in a similar manner. The petrography of the pointing mortar was studied in order to gather evidence of ceramic provenance. This paper concludes that the brick was hand‐ moulded with a silica‐based, predominantly non‐calcareous clay of glacial origin, gathered locally, including fluxes and a high percentage of non‐plastic material. The mineralogy and petrography of the brick, together with the presence of pebbles and a coarse matrix, suggest that the raw clay was probably gathered from a glacial deposit. The presence of abundant pebbles and colour inhomogeneities suggests a lack of processing of the raw clay. The brick was probably fired in clamps at top firing temperatures ranging from 750°C to above 900°C. Transformation of limestone temper involving the breakdown of calcite and the generation of calcium silicates, and the new formation of plagioclase, high‐temperature quartz, hematite and spinel were revealed. The presence of spinel in ‘hot spots’ indicates that fuel was added to the raw clay in order to assist firing.     

EFFECTS OF MILLING: A POSSIBLE FACTOR INFLUENCING THE DURABILITY OF HISTORICAL MORTARS

In their literary texts, some classical Roman authors such as Gaius Plinius Secundus and Marcus Vitruvius Pollio stress the importance of milling when preparing mortars. Following these indications, this work describes the effects of milling between lime (calcium hydroxide) and clay brick powder before and after the addition of water. Starting and resulting materials were investigated by XRPD, SEM/EDS, differential scanning calorimetry and thermogravimetry (DSC/TC), colorimetry, densimetry and porosimetry. Prolonged milling changes the mineralogy of the starting materials and increases their reactivity. The final lime pastes, starting from materials milled for varying periods of time, had different mineralogical and physical characteristics. These results may help to clarify the reasons for the marked differences in durability of some historical mortars.     

Paper 6: Grouting Mortars for Fragmented Bricks and Repair Mortars for Tiles in the Archaeological Site Coudenberg

Abstract

Different grouting and repair mortars were developed and evaluated for the conservation and restoration of fragmented bricks in the walls and floors of the remaining cellars underneath the Aula Magna, the palace’s main banqueting hall, and to fill the lacunae and perform edge repairs of red and blue-grey ceramic floor tiles in the remaining cellars underneath the chapel of the former Palace of Coudenberg in Brussels, Belgium.

To prevent the deposition of lime bloom at the surface of the masonry and to achieve an acceptable colour match of the grout in harmony with the bricks of the Aula Magna, the effect of brick powder added to natural hydraulic lime was studied. The pozzolanic properties and colour match of several historic and modern powdered bricks were investigated. Surprisingly, ancient bricks do not seem to possess higher pozzolanic properties than the more modern ones, although it is supposed that they were fired at lower temperatures. Additional evidence for the pozzolanic reaction of the different brick powder materials was obtained from a simple visual observation of stored samples. After eight weeks all of the samples containing brick powders, fired at low and high temperatures, added to putty lime had hardened under water and were transformed into a remarkably tough material. These results are important, as modern bricks are readily available in large quantities and different colours, which are hence in favour of being used instead of historical material from the site.

For the repair of the ceramic floor tiles different mortars were investigated with mixtures containing talcum, stone or brick powder, pigments, and chalk added to an epoxy binder. The mortars were tested in the laboratory and in situ for their workability and resemblance with the historic floor tiles. The finished mortars showed excellent aesthetic properties with the tiles in situ and good properties to prevent further loss due to human interaction.     

Estimation of the Production Parameters of Very Large Medieval Bricks from St. Urban,Switzerland

The aim of the present study is to determine the production technology of a particular type of large medieval brick. The firing temperature and their soak times are estimated using a combination of colour and fabric, as well as mineralogical, microstructural and open porosity analysis. A replication experiment was carried out in order to validate the estimated predictions, and to give a realistic idea of the time needed to dry and fire each large brick. The experiment also suggests the temperature distribution and firing atmosphere in the kiln, as well as providing an estimate of fuel consumption. Analytical results and replication both provide information to assess the production technology, the time parameters and the firing temperatures involved in the production of the medieval bricks of St. Urban.     

Investigation and analysis of ancient brick carvings of the Liuhe Pagoda in Hangzhou

The Liuhe Pagoda in Hangzhou, China, has a large number of brick carvings from the Southern Song Dynasty (1152 ce ), covering an area of 464 m². However, the exquisite brick carvings in the Liuhe Pagoda have deteriorated due to natural weathering and a high-humidity environment. Through laboratory analysis and on-site nondestructive testing, the physical and chemical properties of the brick carvings of Liuhe Pagoda were investigated, and the weathering mechanism of the brick carvings was further analyzed. The brick carving of Liuhe Pagoda is composed of brick, white plastering and black coating. CaCO₃ is the main component in white plastering, and the black coating on the top surface contains Chinese lacquer. The weathering products of the brick were analyzed and a trace of CaSO₄.2H₂O was found. In addition, the brick carvings with high water content have low Leeb hardness and severe weathering. Therefore, water and soluble salt are the main factors in weathering of the brick carvings of the Liuhe Pagoda.     

中国海南省中和镇古城墙砖的热释光测年研究

采用热释光前剂量饱和指数法对海南省中和镇的8件古城门墙砖样品进行了年代测定研究。由于该地区离海近,粘土中的含沙量非常高,古人在烧制砖时,采用这种粘土作为制砖的原料。烧造时的温度相对高于其它地方烧制的砖。其中4件砖样内部呈灰色,3件砖样内部呈红色,其中1件砖样断面为外围灰色,内部红色。在应用高温细颗粒方法测定这批砖样的年代时,发现样品的高温热释光灵敏度非常差,且不规则,没有"坪曲线",因而无法得出这些古代城门墙砖的具体年代。后采用热释光前剂量饱和指数方法对古砖样品进行了古剂量测定,发现这些样品具有较好的热释光前剂量效应,且样品的热释光灵敏度较高,得到的古剂量具有很好的重复性。热释光测年结果表明,No.2、No.3、No.6、No.8样品的热释光年代分别为:距今590年、575年、530年和580年,为明代早期烧制;No.1、No.4、No.7样品的热释光年代分别为:距今410年、345年和375年,为明代中晚期烧制;No.5样品的年代为距今140年,为清代晚期。经考古人员现场考证,认为No.5样品所处位置存在火烧痕迹。这个火烧时间应该在中国清代晚期,即热释光测定年代。     

BUILDING MATERIALS OF THE THEATRE OF MARCELLUS,ROME*

The building materials of the Theatre of Marcellus, 44–11 bce , reflect Roman builders' careful selections of tuff and travertine for dimension stone and volcanic aggregates for pozzolanic concretes. The vitric–lithic–crystal Tufo Lionato tuff dimension stone contains a high proportion of lava lithic fragments, which increase its compressive strength and decrease water sorption, enhancing durability. Sophisticated installations of travertine dimension stone reinforce the tuff masonry, which is integrated with durable concrete walls and barrel vaults. The pozzolanic mortars of the concretes contain harenae fossiciae mainly from the intermediate alteration facies of the mid‐Pleistocene, scoriaceous Pozzolane Rosse pyroclastic flow. They have pervasive interpenetrating pozzolanic cements, including strätlingite, similar to high‐quality, imperial era mortars. Concrete walls are faced with refined Tufo Lionato opus reticulatum and tufelli, and opus testaceum of fired, greyish‐yellow brick. The exploratory concrete masonry, which includes some of the earliest examples of brick facings and strätlingite cements in Rome, and the integration of these materials in complex architectural elements and internal spaces, reflect the highly skilled workmanship, rigorous work‐site management and technical supervision of Roman builders trained in republican era methods and materials.     

Adipocere Inside Nineteenth Century Femora: The Effect of Grave Conditions.

Adipocere has, infrequently, been reported from archaeological contexts normally on the external surface of bodies. In contrast to those cases, this study focuses on a white, powdery and greasy substance found inside two right human femora during sampling. These samples were obtained from two identified individuals buried in the late 19th century, who were exhumed from a rock‐cut and a brick‐lined grave in a steeply sloping graveyard with wet soil conditions. Both individuals were buried in coffins. Fourier transform infrared spectroscopy was used to test the composition of the substances, and both were found to conform to the spectrum of adipocere. This is likely to be a breakdown product of the fats in bone marrow in an anaerobic, moist environment mediated by bacteria. None of the other individuals (n = 6) buried in similar graves displayed evidence of adipocere; this includes those whose femora were in a similar state of preservation (n = 4). Contemporaneous data on precipitation for the month of burials do not highlight any obvious trends, but one of the individuals was found in a water‐logged grave. The similar preservation of other femora buried in brick‐lined graves highlights the interplay of multiple factors in the formation and degradation of adipocere. More importantly, it demonstrates differential preservation, which may impact on DNA and other biomolecular research. Furthermore, this adds to the limited data currently available on adipocere found in archaeological contexts. Copyright © 2013 John Wiley & Sons, Ltd.     

LANDSCAPE TRANSFORMATIONS IN THE HISTORICAL CAPITALS OF LITHUANIA DURING THE 13TH‐14TH CENTURIES

The castles of Kernav?, Trakai and Vilnius define the core territory of the nascent Lithuanian state. The transformation of the landscape in order to create power centres within the territory of Lithuania at the end of the 13^th century into the 14^th century is a testimony to the ambitions of the ruling Gediminid dynasty. The article presents the results of research carried out in 2018–2019 based on LiDAR data analysis, geophysical surveys, and archaeological investigations with minimal destructive impact. To reconstruct the paleorelief of the landscape, pedological methods were applied. In Kernav?, the most extensive landscape transforming works relate to the construction of hillforts: the steep ridges of the Neris river valley were artificially separated from the upper terrace and thereby transformed into two hillforts, separated by a defensive moat. For the construction of a brick castle in Old Trakai, a site exploiting the advantages of the natural terrain was chosen. Here a suitable location was found that could with few efforts be transformed into a hillock encircled with a moat. The brick castle at New Trakai was built on a peninsula going into a lake and further separated by deep moats. In scholarly writings, it has been assumed that this hillfort was of artificial origin. But the research has challenged this by demonstrating that the hillfort of the Peninsula Castle in New Trakai was merely a transformed glacial hill.     

Carbopol 934树脂作为清洗材料的应用研究

在对文物进行保护处理过程中,清洗是非常重要工作之一。新的清洗材料、清洗工艺的研究,对文物保护技术的发展具有重要价值。本研究对Carbopol 934树脂应用于纺织品清洗的清洗效果、清洗工艺进行了研究,并对其在纸张和砖石文物上应用的可能性进行了尝试。研究结果表明,Carbopol 934树脂应用在纺织品清洗中具有作用时间长、扩散小的优点;同时应用隔离层能减少残留,达到更好的清洗效果;可有效地用于砖石、纸张和织物上污垢的去除。     

Preliminary report on the archaeobotanical investigations at Tell Abraq with special attention to chaff impressions in mud brick

Examination of impressions from chaff-tempered mud brick proved rewarding, given the poor preservation of carbonised seed and grain material at Tell Abraq. Individual chaff elements were found to be recognisable from the impressions and it was shown that naked wheat and barley chaff were used as a tempering medium. Charcoal samples indicate that two species of mangrove were present, one of which is no longer found in the area. Tamarisk and Ziziphus were also present. Date charcoal was common. This study remains preliminary, and further sampling and analyses have been planned for the future.     

Recent Archæological Researches in Rome

Luminescence dating has been applied to ceramic bricks sampled from a selection of English medieval ecclesiastical and secular buildings in Essex, Kent and Lincolnshire, ranging in age from the fourth to the late sixteenth centuries. The results obtained for the Anglo-Saxon churches, which included Brixworth, confirmed the reuse of Roman brick in all cases. The dates for the earliest medieval brick type indicate that brick making was reintroduced during the eleventh century, a century earlier than previously accepted, and dates for bricks from the same secular Tudor building indicate that the practice of recycling of building materials during the late medieval period was also applied to brick.     

‘Would I were in an alehouse in London!’: a finds assemblage sealed by the Great Fire from Rood Lane,City of London

During the development project at 20 Fenchurch Street in the City of London, archaeological excavations were undertaken adjacent to Rood Lane. This uncovered part of a 16th- to mid 17th-century brick built cellar which had collapsed sealing in situ pottery, glass, clay tobacco pipes and a stove tile, an event interpreted as the result of the Great Fire of London in 1666. The composition of this artefact assemblage suggests it was derived from a property used to providing large-scale entertainment, with a high proportion of the material associated with drinking. This article situates this group within the context of other similarly dated victualling establishments from the City of London.     

RESEARCH REPORT: MAGNETIC INVESTIGATIONS AND THE AGE OF A MEDIEVAL KILN AT KUNGAHÄLLA (SOUTH‐WEST SWEDEN)*

The results from a magnetic survey and archaeomagnetic investigation of a medieval brick kiln at Kungahälla in Bohuslän (south‐west Sweden) are reported. Detailed magnetic total field and magnetic gradient measurements over known traces of the kiln showed marked local magnetic anomalies of up to 200 nT, revealing the rectangular shape of the kiln remains. Palaeomagnetic investigations of the remanent magnetization of 12 bricks from the kiln floor gave precise definitions of both the direction of the archaeomagnetic field [(D_m, I_m) = (66.7°, 8.8°), k = 655, α₉₅= 1.7°] and the palaeointensity [B_m= 69.0 ± 3.6 µT]. An archaeomagnetic date is obtained by comparing the direction of the archaeomagnetic field found in the kiln with a geocentral dipole‐transformation of the British master‐curve for secular variation. Of two possible archaeomagnetic dates (ad 1280 ± 50 or ad 1480 ± 50), the ad 1280 ± 50 age is in good accordance with the C‐14 ages and archaeological dates as well as with direct historical evidence, whereas a c. 100 years younger TL date appears to be too young.     

Invasive cordgrass (Spartina spp.) in south‐eastern Australia induces island formation,salt marsh development,and carbon storage

Invasive vegetation species can lead to major changes in the geomorphology of coastal systems. Within temperate estuaries in the southern hemisphere, especially Australia and New Zealand, the cordgrass Spartina spp. has become established. These species are highly invasive, and their prolific growth leads to the development of supratidal environments in formerly intertidal and subtidal environments. Here, we quantified the impact of Spartina invasion on the geomorphology and sequestration capacity of carbon in the sediments of Anderson Inlet, Victoria, Australia. Spartina was first introduced to the area in the 1930s to aid in land reclamation and control coastal erosion associated with coastal development. We found that Spartina now dominates the intertidal areas of the Inlet and promotes accretion (18 mm/year) causing the formation of over 108 ha of supratidal islands over the past 100 years. These newly formed islands are calculated to potentially contain over 5.5 million tonnes of CO₂ equivalent carbon. Future management of the inlet and other Spartina‐dominated environments within Australian presents a dilemma for resource managers; on the one hand, Spartina is highly invasive and can outcompete native tidal marshes, thereby warranting its eradication, but on the other hand it is likely more resilient to rising sea levels and has the potential for carbon sequestration. Whether or not the potential advantages outweigh the significant habitat change that is anticipated, any management strategies will likely require additional research into costs and benefits of all ecosystem services provided by Spartina including in relation to nutrient cycling, shoreline stabilisation, and biodiversity as well as in response to the longevity of carbon found within the sediments.     

Industrial Building Design and Economic Context: The Railway Freighthouse in Chicago, 1850–1925

Abstract

The rapidly increasing scale and broadening scope of railway freight operations in Chicago between 1850 and 1925 offer a unique opportunity to study the impact of factors affecting North American freighthouse design. Early freighthouses were small, single-storey brick and mill buildings designed to handle the straightforward exchange of freight shipments, while later freighthouses were large, multi-storey, concrete and steel structures featuring mechanised freight handling systems. A simple analytical framework for studying factors influential in freighthouse size, function and design is provided. Market factors include developments in the railway freight marketplace, notably freight traffic growth and the need to offer storage and warehousing services. Supply factors include those factors that limited or facilitated changes in design resulting from changes in the marketplace, notably local freight delivery costs, increases in land values, advances in construction materials and labour-saving freight handling technologies.     

Radical changes in Islamic glass technology: evidence for conservatism and experimentation with new glass recipes from early and middle Islamic Raqqa,Syria*

The chemical analysis of excavated glass fragments from dated archaeological contexts in Raqqa, Syria, has provided a detailed picture of the chemical compositions of artefacts deriving from eighth to ninth and 11th century glassmaking and glassworking activities. Evidence for primary glass production has been found at three excavated sites, of eighth to ninth, 11th and 12th century dates; the first two are discussed here. The 2 km long industrial complex at al‐Raqqa was associated with an urban landscape consisting of two Islamic cities (al‐Raqqa and al‐Rafika) and a series of palace complexes. The glass fused and worked there was presumably for local as well as for regional consumption. Al‐Raqqa currently appears to have produced the earliest well‐dated production on record in the Middle East of an Islamic high‐magnesia glass based on an alkaline plant ash flux and quartz. An eighth to ninth century late ‘Roman’/Byzantine soda–lime recipe of natron and sand begins to be replaced in the eighth to ninth century by a plant ash – quartz Islamic soda–lime composition. By the 11th century, this process was nearly complete. The early Islamic natron glass compositional group from al‐Raqqa shows very little spread in values, indicating a repeatedly well‐controlled process with the use of chemically homogeneous raw materials. A compositionally more diffuse range of eighth to ninth century plant ash glass compositions have been identified. One is not only distinct from established groups of plant ash and natron glasses, but is believed to be the result of experimentation with new raw material combinations. Compositional analysis of primary production waste including furnace glass (raw glass adhering to furnace brick) shows that contemporary glasses of three distinct plant ash types based on various combinations of plant ash, quartz and sand were being made in al‐Raqqa during the late eighth to ninth centuries. This is a uniquely wide compositional range from an ancient glass production site, offering new insights into the complexity of Islamic glass technology at a time of change and innovation.