In Situ Preservation – Application of a Process-Based Approach to the Management of Underwater Cultural Heritage
Session 7
Preservation and conservation of wet archaeological materials and site management
Over the past few decades, the archaeological community has been moving away from the more traditional methods of excavation and recovery of underwater cultural heritage (UCH) towards a less intrusive management approach, essentially involving the preservation of sites in situ. Over the years, different remediation strategies have been utilised in order to protect these sites in situ and most of the techniques involve reburial of sites. Reburial may be an appropriate means of stabilising and decreasing the deterioration rate of a site, however, there needs to be a holistic approach to the study of the environment, before and after reburial to gain a full understanding of the changes that are occurring on the site and determine the effectiveness of the technique.
This paper outlines a process-based approach to the development of appropriate long-term management strategies for UCH sites.
Vicki Richards
November 2011
Micromorphological and chemical characteristics of waterlogged archaeological bamboo
Session 7
Preservation and conservation of wet archaeological materials and site management
Waterlogged archaeological bamboo works such as bamboo slips and bamboo baskets, etc. were unearthed during excavations of the Mado shipwreck No. 1 excavation in 2009. Despite the number of bamboo artefacts recovered from underwater sites, the characteristics and conservation of waterlogged archeological bamboo unearthed from the sea have not been studied sufficiently.
Following examinations of waterlogged archaeological bamboo using optical, scanning electron and transmission electron microscopy, it was found that waterlogged archaeological bamboo has been invaded by soft rot fungi and erosion and tunneling bacteria. This is similar to the usual micromorphological decay characteristics of waterlogged archaeological wood. Unlike waterlogged wood however, waterlogged bamboo demonstrated differences in aspects of decay in the interlayer structure of the fibre cell and in the degree of decay, depending on the parts of the bundle sheath examined.
Chemical analyses suggested that, as in waterlogged archaeological wood, cellulose and hemicellulose were significantly degraded and the content of lignin was relatively high in waterlogged bamboo.
Mi Young CHA
November 2011
From Infrastructure to Icon: a Historical and Archaeological Analysis of the Randell Dry Dock
Session 7
Preservation and conservation of wet archaeological materials and site management
On the banks of the Murray River in the small township of Mannum, South Australia, lies an impressive and rare feat of early colonial maritime infrastructure; the Randell Dry Dock. Originally constructed as a timber floating dock in 1873, it was purchased by Captain William Randell and towed to Mannum. The imposing structure docked over half of all the paddle steamers on the Murray-Darling river system before being superseded in 1927. It is now only one of a handful of timber docks from this period still existing internationally. Archaeological investigations have been minimal on maritime infrastructure sites along the River Murray. A heritage trail has been implemented by the SA Department of Environment and Natural Resources and the SA Tourism Commission. The Randell Dry Dock is part of this trail and on the State Heritage Register. Archaeological investigations have revealed new information about the dock’s unique construction. This paper will outline the history and construction of this architectural gem, the seriousness of its current condition, and the ongoing fight against the clock by archaeologists and the local community to protect this rare and significant example of South Australian Murray River history.
Britt Burton
November 2011
The Australian Historic Shipwreck Protection Project
Session 7
Preservation and conservation of wet archaeological materials and site management
Australian wooden shipwrecks represent significant submerged heritage sites with huge potential to inform on historic connections, technological innovation and early colonial behavioural systems. Their archaeological potential is unfortunately often under severe threat from natural and human impacts. The Australian Historic Shipwreck Protection Project has recently been granted a large Australian Research Council (ARC) Linkage grant to investigate the excavation, reburial and in-situ preservation of wrecks and their associated artefacts, which are at risk. This project will focus on Clarence (1850), a historically significant colonial wooden trading vessel, and brings together the disciplines of behavioural archaeology, maritime archaeology, conservation sciences and maritime object conservation. The vessel lies in Port Phillip Bay in Victoria only a few hours from Melbourne by boat and by land. The overarching theoretical focus will be on shipwreck site formation models as well as the potential of wooden historic wrecks and assemblages to elucidate early colonial history and shipbuilding.
One of the main aims of the project is to try and develop a protocol for the rapid excavation, detailed recording and subsequent in-situ preservation of significant shipwrecks and their associated artefacts, at risk. This work will foster the development of a consistent national methodology for shipwreck and artefact storage and preservation underwater and assist in developing a strategy for the in-situ preservation of endangered historic shipwrecks. This work will also be critical to the future development of national, and possibly international, policy and technical guidelines for site managers of historic wrecks.
The project will run for a period of three years. During the field work components the investigators from the University of Western Australia (UWA), the Australian National University (ANU), Monash University and the Western Australian Museum (WAM) with support from research associates and practitioners from the ten partner organisations will operate from a jack-up barge located over the site including purpose built laboratories where they will excavate circa 25-50% of the Clarence site, conduct imaging (x-ray and optical) of recovered artefacts, conserve at-risk materials (where required) and rebury structural elements and associated artefacts using a combination of in-situ preservation techniques and initiate a long-term monitoring programme for the site. Excavation methodology will be overseen by Mark Staniforth, Peter Harvey (Heritage Victoria) and Peter Veth; conservation and in-situ preservation protocols, analyses and pre- and post-reburial monitoring by Ian MacLeod and Vicki Richards; imaging co-ordinated by Dudley Creigh (and colleagues) and Andrew Viduka; geoarchaeology and Geographical Information systems (GIS) by Tony Barham and Masters of Archaeological Science candidates.
Peter Veth
Andrew Viduka
Mark Staniforth
Ian MacLeod
Vicki Richards
Anthony Barham
November 2011
The post-treatment deterioration of marine
archaeological wood – where to now?
Session 7
Preservation and conservation of wet archaeological materials and site management
As waterlogged wood is ubiquitous in excavation sites, being used for structures (ships and buildings), tools, personal effects and for decorative artefacts, this material has been the subject of most conservation research and treatment over the past few decades. The development of disfiguring white deposits on treated timbers from the Skuldelev Viking ships from Roskilde Fjord in the late 1970s was initially treated as a minor cosmetic problem. The seriousness of the situation was soon realized when more timbers were affected and the destruction of timber tissue became evident. Similar problems have also been encountered with the Batavia timbers from Western Australia, the Shinan ship in Korea and artefacts from the Mary Rose in England. Problems associated with the presence of iron corrosion products in treated, formerly waterlogged timbers were further highlighted in 2000 with the development of highly acidic regions on some Vasa timbers and associated artefacts. These outbreaks on the Vasa were thought to be related to the inability of the climate control system to keep the relative humidity in the gallery below 60%. These post-treatment developments prompted a significant period of focused research and conservation activities, this time involving multi-faceted analyses and the development of strategies to address a problem that has the potential to affect all waterlogged timbers excavated from anaerobic sites. This paper reviews the current situation regarding the role that iron species play in promoting the formation of acidic species and in catalyzing the oxidation of reduced sulfur species, cellulose and polyethylene glycol and the steps being taken to reduce post-treatment deterioration of formerly waterlogged wood. The implications for future conservation treatments of waterlogged wood are discussed.
Godfrey, I. M.
Richards, V. L.
Cha, M. Y.
November 2011
In-situ preservation In Tropical Seas:
Case Study on the Avondster Shipwreck
Session 7
Preservation and conservation of wet archaeological materials and site management
The VOC ship Avondster sunk on 2nd July 1659 when anchoring near the beach in Galle Bay, geographically located in the southern part of Sri Lanka. She was re-discovered in 1993 and subjected to a series of research projects including excavation in the bow, stern and mid-ship areas. Due to construction work in Galle Harbour it was important to protect the shipwreck in situ. The environment in the Galle Bay badly affected the wreck site and it was a big challenge to overcome all the harmful factors that were likely to damage the remains of Avondster.
In order to preserve Avondster a plastic net was introduced as a protective layer over the wreck site. This was monitored constantly throughout and after the research period. The protective layer was used over the fragile timbers for nearly 8 years before a violent tsunami hit Galle Bay in December 2004. Despite the serious damage caused on the land by the tsunami, it had less effect on the site and the covering-plastic net was still intact. From that time on monitoring has continued every two months.
This paper discusses in detail the present condition of the in situ protection and its validity as a preservation technique in the conditions found in tropical seas.
Chandraratne Wijamunige
November 2011
The Subcritical Mass-Treatment of a Range of Iron Artifacts from Varying Contexts
Session 7
Preservation and conservation of wet archaeological materials and site management
The use of subcritical fluids for the treatment of archaeological and marine archaeological iron artifacts has been under experimentation at the Clemson University’s Warren Lasch Conservation Center (WLCC) since 2003 and has shown promise of providing solutions to some of the issues related to the more traditional desalination treatments: Treatment times are but a fraction of those required by the soaking methods; chloride readings are brought to near-negligible levels; desalination can be carried out with or without prior deconcretion; solutions are maintained in sealed containers for the duration of the treatments; and positive results have been seen so far with tests for long-term stability of treated artifacts. Particularly remarkable has been the effect the process appears to have had on corrosion matrices containing the chloride-hosting iron oxyhydroxide, Akagenéite (β-FeOOH) on artifacts that have been allowed to dry out. Results have shown a significant reduction in the quantities of this phase – often linked to the continuation of active corrosion processes within iron artifacts – through transformation into more stable corrosion products such as magnetite and hematite. Experiments carried out to date have not only involved single samples and artifacts, but testing has progressed to a stage where numerous artifacts have been successfully stabilized simultaneously in the same batch. The work presented describes three of such desalination treatments. The first run included a single wrought iron ballast block from the H.L. Hunley, a confederate Civil War submarine lost in battle in 1864. This was followed by the first batch run on five similar ballast blocks and a second with nine iron artifacts of varying composition, context and condition, selected from the National Park Service (NPS - USA) curatorial collection.
Nasanen, L. M. E.
González-Pereyra, N. G.
Cretté, S.A.
November 2011
Conservation Research and Treatment Programs: Case Study of Ancient Boat Site in Rembang Regency
Session 7
Preservation and conservation of wet archaeological materials and site management
The ancient boat was made around the 7th century A.D. It was found on July 26, 2008 at 07.30 p.m. at Punjulharjo Village, Rembang Regency, Central Java Province, Indonesia. The boat site is covered by soil as deep as two metres and is located at the southern of coastline with a distance of 0,5 to 1 km. When the ancient boat was found, the shape of the boat was still intact. Size of the boat is 15 metres length and 5 metres width. Not only the shape is relatively intact but also the disclosure of data of the archipelago's unique technology could be held within this boat that was almost complete. Tambuku is the type of palm fibre rope, pegs was used in the boat and other components that have never been encountered before is really a remarkable data essential for the development of maritime archaeology, especially in Indonesia. The ancient boat has important value for history, science, technology, and culture. As an important cultural asset and potential, its existence must be well managed and sustainable by optimizing in situ conservation.
Conservation research should be conducted to identify the ancient boat such as the kind of materials for making a boat, condition of boat materials, the site condition of the boat, and environmental condition. Conservation method should be based on the results of diagnosis in the laboratory as well as in the field.
In situ conservation is another important approach to preserve the ancient boat, which simultaneously give positive impacts to tourism aspects and development to the region.
Waluyo Agus Priyanto
November 2011
Keeping artefacts in situ and preserving them once out of the water:
Daily questions for a conservator-restorer in marine excavations
Session 7
Preservation and conservation of wet archaeological materials and site management
Working on a shipwreck means analyzing its cargo, taking samples and when access is possible, studying the naval architecture. After publication, in many cases, closing and securing the site is possible.
Excavating a settlement or an underwater city calls first to understand the site with a non-intrusive survey. State of the art investigation equipment such as multi-beam sonar systems, sediment sounder, magnetometer with nuclear resonance allows us to start drawing the map of the establishment. Diving is necessary to check details, to make stratigraphic sections, or to understand structures. This brings up often thousands of artefacts.
Keeping most of the artefacts at the bottom of the sea and storing them in a special underwater storage place with an inventory number is a good solution, but it is also necessary to bring some objects in an atmospheric environment for study, as a reference or because they are too fragile, precious or unique to be left underwater. They will be then on display in a museum or will tour the world.
We are therefore regularly confronted with a sudden flow of artefacts literally inundating a laboratory but also drying out its budget.
Our experience through sunken cities excavations in Egypt has taught us ways to anticipate these waves of artefacts in needs of treatment and to adapt our policy of excavation and the techniques for underwater conservation-restoration.
Olivier Berger
November 2011
The Introduction of Conservation Treatment of Maritime Artifacts in Korea
Session 7
Preservation and conservation of wet archaeological materials and site management
Since 1976, the underwater excavation program, which began with the Shinan ship, has yielded some 94,500 relics and eleven shipwrecks (including two foreign ships) from 18 sites in Korea. To conserve each material appropriately the artifacts salvaged from the sea were safely conserved on site and then moved to the laboratory. In particular the hulls of the ships were salvaged by separated pieces. Treatment of PEG 2-step method was applied for several years. The two ship hulls (Shinan and Wando) have been displayed after conservation treatment, and one is being prepared for a new display.
We first tested pre-conservation treatment for safe stabilization and then have applied the best method of pre-study results to the ceramics, wooden tags, metallic objects, bones, crops etc. We excavated many bamboo artifacts after 2009, and are currently studying pre-conservation treatment.
Dr Whan-suk Moon
November 2011