Application of veratraldehyde as a temporary consolidant for relics at underwater cultural heritage sites

Because it is often difficult to preserve fragile relics in situ at underwater cultural heritage sites, it is sometimes necessary for relics to be extracted and moved to a controlled environment on land for protection and study. This paper discusses the feasibility of using the volatile organic compound veratraldehyde as a temporary consolidant for underwater fragile relics extraction. The results show that different materials (iron, tile, sand, wood) under water can be bonded together and extracted when using veratraldehyde. The fact that veratraldehyde is difficult to spread on the surface of underwater objects is a problem that can be solved by adding a layer of strong hydrophobic polypropylene (PP) fibres onto the object, serving as a ‘package' for the relics. Under laboratory conditions, we used veratraldehyde and PP fibres to extract broken tiles from underwater sand onto an exhibition stand. The broken tiles, in both condition and distribution, were safely and completely retained as the veratraldehyde was slowly removed by the soaking process. This work fills a gap in knowledge about temporary consolidant materials in underwater archaeology, and provides a new method for extracting underwater fragile cultural relics without damaging them.     

The application of the Submetrix ISIS 100 Swath Bathymetry system to the management of underwater sites

Over the last decade analysis of the HMS Pomone wreck scattered below the Needles has aimed to correlate artefact positions with their terrain and aid research into the distribution process of the wreck-site. However, physical limitations faced by divers on the site have restricted progress. The search for a solution to the difficulties of archaeological surveying was resolved by the Submetrix ISIS 100 system when a bathymetric survey of the wreck-site was performed in a single day. It has provided a contoured terrain model that can aid further investigations and help plans for the future management of the site.     

Avian egg-shell from archaeological sites

Avian egg-shell occurs fairly commonly on archaeological sites, particularly in alkaline deposits. It is rarely studied in detail. Egg-shell structure is described briefly below and features which may be of value for identification purposes are discussed. Egg-shells from 14 archaeological sites are tentatively identified as goose, domestic fowl, duck and guinea fowl. It seems likely that confident identification should ultimately be possible using a combination of features. This should yield information complementary to osteological evidence for the history of the utilization of birds and their eggs.     

Temporary consolidation and packaging of fragile cultural relics at underwater archaeological sites to maintain their original state during extraction

The flexible sponge/epoxy composite can wrap underwater artefacts in any shape and forms a protective shell after curing, thus effectively wrapping and reinforcing the artefacts. However, the hydroscopicity of the sponge itself limits the underwater application of the sponge/epoxy composite. In this study, a novel polyurethane sponge was prepared by modified with super-hydrophobic multi-wall carbon nanotubes (SH-MWCNTs@PU sponge). Compared with the pristine PU sponge, the water-contact angle on the surface of SH-MWCNTs@PU sponges increased from 103.3 ± 1.82 to 152.6 ± 1.54^o, and oily epoxy resin was able to cover the surface completely. The study shows that when SH-MWCNTs@PU sponges/epoxy resin composite material is used underwater, it prevents both water from entering the sponge and also the inside epoxy resin from overflowing into the water. Moreover, the composite materials have excellent toughness after reinforcement under water (flexural strength = 3.56 MPa) and the soft sponges can be moulded to wrap any type of underwater artefacts. In the laboratory, when taking a broken, three-dimensional blue-and-white porcelain pot as a research subject, the entire retrieval process—temporary stabilization, packaging, extraction and reinforcement material removal—was simulated to evaluate systematically all the technological aspects of safely excavating fragile underwater relics.     

Phosphatic mineralization of seeds from archaeological sites

Recent investigations of botanical material from archaeological sites have provided seeds and plant remains exhibiting a crystalline or semi-crystalline appearance. X-ray diffraction and partial chemical analysis have revealed that the particular plant materials had been replaced by calcium phosphate. Using systematic sampling and retrieval techniques a significant body of data has been accumulated. Most mineralized botanical evidence has been recovered from faecal deposits, in particular cess pits and garderobes, and has provided an important source of information about aspects of diet of past populations.     

Exotic plants from Roman waterlogged sites in London

An extensive range of plant remains was recovered from seven Roman sites in London where waterlogged conditions had resulted in good preservation. In the majority of cases the “artificial” nature of urban deposits precludes any objective ecological interpretation, since the allochthonous origin of the plant remains cannot be satisfactorily established. However, the presence of exotic plants in dated deposits is of both botanical and archaeological significance and is here artificially treated as an autonomous group. This varied group of plants (excluding carbonized cereals) is arranged according to their use and put in archaeological and botanical perspective. Species such as cucumber (Cucumis sativa), gold of pleasure (Camelina sativa), peach (Prunus persica), olive (Olea europaea) and millet (Panicum miliaceum) have not been recorded from Romano-British sites before. For many of these plants their status, either as introductions or imports, is uncertain. Whichever is the case, it is clear that a wide variety of economic plants was available in Roman London.     

Archaeomagnetic data from three Punic sites in Tunisia

Archaeomagnetic analyses on bricks and slag fragments from kilns have been undertaken. Four new archaeomagnetic directions and two new archaeomagnetic intensities have been reported for three Punic sites in Tunisia. The SCHA.DIF.3K archaeomagnetic model gives the most consistent age estimates, in agreement with the archaeological ages for three of the four analyzed kilns. The archaeomagnetic models appeared to be surprisingly proficient both using archaeodirections and intensities for El Maklouba. The existence of kilns from different chronological archaeological phases (4th–3th century BC and 2nd–3rd century AD) has been confirmed for this site. The archaeological hypothesis that associates the kiln in El Gaala with the neighboring Punic necropolis is compatible with the archaeomagnetic data obtained from the kiln, though a modern use or remagnetisation of the kiln cannot be excluded.     

Some observations on puff-balls from British archaeological sites

The occurrence of the puff-ball Bovista nigrescens in four British archaeological sites, approximately 2000 years old, is investigated, and the related Calvatia utriformis is reported for the first time in archaeological excavations from one of these sites. The circumstances of their discovery at two of these sites (Skara Brae and Vindolanda) strongly suggest that they did not arrive there fortuitously. The puff-balls are considered to have been used as haemostatic agents and/or as tinder. A detailed morphological comparison of early specimens with present-day material is made.     

Archaeomagnetic data from four Roman sites in Tunisia

Archaeomagnetic analyses on bricks and slag fragments from kilns have been undertaken. The initial aim of the paper was to constraint the age of four Roman sites in Tunisia (Neapolis, Pheradi Majus, Leptiminus and Sullecthum) using either archaeodirections or archaeointensities. However, the archaeomagnetic models appeared to be only proficient using directions. It has been established that the Neapolis' studied kiln was probably active until the early 6th century AD, whereas the kilns investigated in Pheradi Majus were probably active until the middle 5th century AD. Measured archaeointensities point to higher values than those predicted by the models during the whole range of possible ages for the studied sites.     

微纳米气泡清洗“南海一号”出水瓷器的安全性评价研究

随着我国水下考古事业的蓬勃发展,出水文物的科学保护已成为亟待解决的重要问题。表面各种附着物的清除是出水瓷器清洗的难点,现有的机械和化学清洗方法均存在着一定的局限性。在试清洗实验中,微纳米气泡展现了存在时间长、传质效率高、表面电荷形成的ζ电位高等不同于普通气泡的物理化学特性,对出水瓷器具有优越的清洗效果,因此有必要进一步对该清洗技术开展科学的安全性评价。选取打捞自"南海一号"的18件瓷片样品,进行了现状调查与病害检测,使用色差分析、光泽度分析、显微分析、显微测量等方法开展了安全性评价研究。实验结果表明,未发现微纳米气泡清洗技术会导致出水瓷器自身的颜色与光泽度产生明显变化,未发现其会导致瓷器釉面损伤,也未发现其会对瓷器已有裂缝产生影响。现有的评价结果表明,微纳米气泡清洗技术对于出水瓷器是基本安全的,为该技术在文物保护工作中的实际应用提供了重要依据。     

Archaeomagnetic dating of archaeological sites from Switzerland and Bulgaria

Baked materials from three archaeological sites in Switzerland and one in Bulgaria have been examined and dated archaeomagnetically. The detailed rock-magnetic properties of the burnt clay collected have already been studied therefore and have been published elsewhere (Geophysical Journal International 153 (2003) 146). The main aim of this paper is to determine the terminus ante quem for the last firing of the clay collected from pottery kilns or burnt layers. The directional and intensity results of the ancient geomagnetic field corresponding to the time of the structure's last firing are given for each site. These geomagnetic parameters are then compared with reference curves to provide archaeomagnetic dates for the last use of the kilns. Application of archaeomagnetism as a dating tool is only possible for those regions that already have reference curves. Bulgaria is fortunate in having established reference curves covering almost the last 8000 years. Two Swiss sites were dated using only directional results on the basis of existing palaeodirectional results for Switzerland as well as the French directional reference curves. The archaeomagnetic dates of three of the sites were then compared to archaeological evidence and available radiocarbon dates. The palaeointensity data obtained from this study will enrich the existing archaeomagnetic database for western Europe.