News December 2005

During 2005 the reburial site in Marstrand has been visited twice. First in May, when the site was inspected visually and sediment cores for further analyses were taken inside the reburial trench as well as outside. The areas that had been refilled with sediments in 2004 looked good and kept the initial covering level. Data from the datalogger was collected and the logger again put back into the reburial trench for its final logging period

In October it was time for the third retrieval of buried samples. This was done in one day in the same way as previous times (see news from 2003 and 2004) and again we were lucky with sunny and mild weather. Due to the problems with sediment that had compacted since the start of the project 2002, it was decided to retrieve not the intended samples for 2005 but samples labeled 2050, which had been nicely covered with sediments all the time. This was especially important for the wood samples. The logger was this time brought back home, since we have now got environmental data from a whole year. Present also this time were and David and Kristiane from the National Museum in Denmark, Thomas and Staffan from the Bohus County Museum, and Inger from Studio V ästsvensk Konservering

The wood, metal and silica samples were in November sent to respective co-ordinator and the samples of other organic material were excavated by the co-ordinator herself at SVK and brought back to Norway.

Whit this retrieval we have come to the end of the first phase of the reburial project and it is now time to analyze, compare and draw conclusions from all of the collected data. A final report should be completed at the end of June 2006. Before that we hope to have a seminar with all participants in early to mid May 2006 in G öteborg. Until then, buon lavoro!

News September 2004

The project Reburial and Analyses of Archaeological Remains (RAAR) was presented at the 9th ICOM-CC group on Wet Organic Archaeological Materials Conference in Copenhagen in June 2004. A paper (pdf 60 kB) will be published in the proceedings of the conference. During this well planned and interesting conference a working group meeting was held with almost all of the co-ordinators in the RAAR project present (see Memo for more information (pdf 1.07 MB) ).

The project was also presented in early September with a poster at the 6th European Commission Conference on Sustaining Europe’s Cultural Heritage: From Research to Policy. Head of conservation at SVK, Gunilla Lagnesjö, attended the conference and could report that the poster was positively mentioned and the project was congratulated for its long-term aspect. Unfortunately it did not win the prize for best poster, so there will be no fight about who is going to Malta for holidays!!

Ebba in the water

On the 22 and 23 of August 2004 the second annual inspection and retrieval of the buried material samples in the harbour of Marstrand was performed. The work went well during two beautiful and sunny days. Present this year were Thomas and Jens from the Bohus County Museum, Inger and Ebba from Studio Västsvensk Konservering and David and Kristiane from the National Museum in Denmark.

Macro photo of Cu coupons

Metal samples were lifted for the first time from the sediments. These were photographed and then immediately vacuum packed together with oxygen absorbents and put in cool storage. David and Kristiane downloaded data, calibrated and refurbished the logger and measured redox-potentials on the metal samples. The datalogger has collected environmental data during a three months period and results will be presented on this web-site later in the year. The logger was put back into the reburial trench. However it was decided not to put the oxygen sensor back into the dip-well buried in the sediment, but instead to let the sensor measure the oxygen level in the seawater.

Four sediment cores were taken in the reburial trench and outside the disturbed area. Two will be analysed by the National Museum in Denmark and two will be sent analysed by our Australian co-partners.

During the inspection in April this year it was noted that the sediments in the reburial area had compacted since September 2002, resulting in partial exposure of some of the wood units. This time the exposure was identified and measured. After discussion with the co-ordinator it was decided to refill with sediments to the initial level. This was also done.

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Wood samples August 2004

Copper coupons (detail)

Macro photo of wood samples

Datalogger August 2004

News April 2004

The environmental monitoring program continues

On the 22 of April David Gregory, co-ordinator of the sub-project Monitoring the Environment of the Re-burial Site at Marstrand, and his college Kristiane Strætkvern, both from the National Museum in Denmark, visited the Marstrand site. Together with Thomas Bergstrand, one of the project leaders, the site was inspected and environmental monitoring work was conducted.

After having been serviced and refurbished the datalogger, which purpose is to monitor pH, redox and DO of the reburial environment, was once again placed in the reburial trench. The three sensors are placed in specially designed permeable acrylic glass tubes, so called dipwells, which have been put into the sediments. The principle is that the sensors measures the pH, redox and DO of the water that flows through the permeable tubes. The environmental monitoring using the datalogger is meant to continue for one year from April 2004 with a regular three monthly retrieval of data and service. Hopefully the logger will do the work without failures during the following three months period.

Conventional sediment cores were also taken both in the reburial area and in an undisturbed area close to the reburial trench. These sediment samples will be analysed in the laboratory at Brede and the result compared with the data retrieved from the datalogger. Results will be published at this web-site.

Sediment cores was also taken and sent to the Western Australian Museum to be used in the sub-project Investigation of the Effects of Reburial on Metals. The co-ordinator Vicki Richards will look at particle size distribution and chemical parameters with relevance for how the metals corrode. The results will eventually be compared with the result from the datalogger and the sediment samples analysed in Denmark.

During the inspection of the site it became obvious that the biological activity is considerable. The wood sample units from SLU are completely covered by marine growth and are hardly recognisable. It was also noted that the sediments in the reburial area had compacted since September 2002, resulting in the exposure of some of the wood units. Therefore the extra unit will be used in the retrieval 2004.

Have a look at the video footings from the Marstrand reburial site.

1. Trench with organic samples (Wmv 1.3 Mb)
2. Trench with metal samples (Wmv 6.7 Mb)
3. Data logger at work (Wmv 2.1 Mb)

Preliminary results from sub-project 4 - wood samples.

Wood samples 2003

The first preliminary results from the wooden samples retrieved the 18th of March 2003 have arrived. The co-ordinator for sub-project 4, Charlotte Björdal, says that after 6 months the reburial shows promising results. The sediments seem to have protected the wooden samples from microbiological decay. Samples of oak, pine and birch buried at 20 and 50 centimetres depth show no signs of decay, whereas the samples exposed in the sea water show degradation by soft rot and tunnelling bacteria on the surface and down to a few millimetres depth.

The first yearly retrieval in September 2003

Lunch break

During the beautiful last day of September 2003 the first yearly retrieval of the material samples planted in Marstrand was successfully accomplished. The site was inspected and photographed and the sediment thickness was measured. The depth of the sediments, from the sea bed to the bottom of the test units, were 47-52 centimetres. This indicates that the sediments have only been slightly compacted during the first year.

The units of sub-project 1, 2 and 3, with material samples packed in crates, were lifted with an air-bag to the jetty where they were packed in heavy duty PE plastic. The sediments in the crates were kept to keep an anaerobic environment. The wooden samples of sub-project 4 were packed in PE tubes under water. On the jetty the water filled tubes were sealed with ducting tape. Thereafter the samples were transported to SVK and kept in cool storage before they were sent off to each respective co-ordinator. It is our hope that the first preliminary results of the analyses can be presented at this website during the winter.

Metals are back on track

Metal samples on the jetty

The re-burial project in Marstrand is very pleased to welcome the Western Australian Museum (WAM) with Vicki Richards and Ian MacLeod as the new co-ordinators of the metals sub-project (sub-project no. 5). Metals are an important but often complicated type of material in archaeology, especially when it comes to the investigation and management of wreck sites. Further knowledge of metals in different re-burial environment is most definitely needed. A parallel re-burial study on the wreck of James Matthew, south of Fremantle on the west coast of Australia, has been initiated by the Western Australian Museum and that study together with results from the Marstrand project will eventually give us important data to help evaluate re-burial as a method as well as give advice how to plan and accomplish preventive conservation under water.

Owing to the generosity of WAM and the department of the Culture and the Arts in Western Australia Vicki Richards were able to visit Marstrand. She brought the metal samples here and helped with the logistics when planting the metals. Thanks to this it was possible to plant the metals in connection to the first retrieval of samples in September. The metal coupons consist of mild steel, cast iron, brass, copper and bronze. Each set of metals are placed on three different depth intervals (totally exposed, just under the sediments and 50 cm below the sea bottom). The iron and non-ferrous coupons are mounted on separate rods and planted in separate rows in a trench close to the other samples to prohibit galvanic and proximity corrosion. Read more about the metals sub-project on this web site (see Investigation of the effect of reburial on metals)

Two retrievals have so far been carried out and results will continuously be presented at this web site. David Gregory is planning another visit to the reburial site in November/December to monitor the environment. Follow the work at this website

March 2003

In late march 2003 the first recovering of wood samples was done. The recovering only included wood exposed for 6 months, while the other kinds of samples will wait until September this year. The wood samples were shipped to SLU in Uppsala for analyses. The result will be published at this webpage later on. Simultaneously as the recovering, David Gregory at the National Museum of Denmark's Centre for Maritime Archaeology commenced the environmental monitoring of the re-burial site (sub project 6). Two cores of samples were analysed with microelectrodes to determine pH, dissolved oxygen, sulphide and redox potential. The preliminary results will, as with the wooden samples, be published soon. A data logger was also placed at the site measuring pH, dissolved oxygen and redox potential. The first data will be retrieved in June later this year.

September 2002

In September 2002 all the units of samples were planted in the Marstrand harbour. The units consist of plastic containers (polyethylene) with the samples attached inside. Subproject 4 (wood) uses a specially designed device to expose samples of wood both at different levels in the sediment and in free water. The types of wood are oak, spruce and birch. To facilitate the annual recovering, units of each subproject were gathered in 'stations'. The units were dug into the bottom of a big trench and covered with sediment from the surrounding sea bottom, which consists of post glacial clay.