See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/308011027

Cover it! The Protection of a Merovingian Burial Ground in Borgharen (Municipality of ), the

Article in Conservation and Management of Archaeological Sites · July 2016 DOI: 10.1080/13505033.2016.1182766

CITATIONS READS 0 154

4 authors, including:

Jan-Willem De Kort Roel Lauwerier Rijksdienst voor Cultureel Erfgoed Ministry of Education, Culture and Science

29 PUBLICATIONS 40 CITATIONS 122 PUBLICATIONS 486 CITATIONS

SEE PROFILE SEE PROFILE

Bertil J.H. Van Os Rijksdienst voor Cultureel Erfgoed

99 PUBLICATIONS 2,007 CITATIONS

SEE PROFILE

Some of the authors of this publication are also working on these related projects:

Odyssee EGK Noord-Holland View project

Charlemagne's Workshops View project

All content following this page was uploaded by Roel Lauwerier on 20 December 2017.

The user has requested enhancement of the downloaded file. Conservation and Management of Archaeological Sites

ISSN: 1350-5033 (Print) 1753-5522 (Online) Journal homepage: http://www.tandfonline.com/loi/ycma20

Cover it! The Protection of a Merovingian Burial Ground in Borgharen (Municipality of Maastricht), the Netherlands

Jan Willem De Kort, Roel Lauwerier, Bertil Van Os & Cees Van Rooijen

To cite this article: Jan Willem De Kort, Roel Lauwerier, Bertil Van Os & Cees Van Rooijen (2016) Cover it! The Protection of a Merovingian Burial Ground in Borgharen (Municipality of Maastricht), the Netherlands, Conservation and Management of Archaeological Sites, 18:1-3, 321-327, DOI: 10.1080/13505033.2016.1182766

To link to this article: http://dx.doi.org/10.1080/13505033.2016.1182766

Published online: 10 Sep 2016.

Submit your article to this journal

View related articles

View Crossmark data

Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ycma20

Download by: [University Library Utrecht] Date: 12 September 2016, At: 04:56 CONSERVATION AND MGMT OF ARCH. SITES, Vol. 18 Nos. 1–3, February–August, 2016, 321–327

Cover it! The Protection of a Merovingian Burial Ground in Borgharen (Municipality of Maastricht), the Netherlands Jan Willem De Kort, Roel Lauwerier, Bertil Van Os and Cees Van Rooijen Cultural Heritage Agency, The Netherlands

A Merovingian burial ground in Borgharen was threatened by development. Plans however could be changed so the site could be preserved. The initial research however showed the bone material was at risk of severe degradation in the near future. In order to determine whether in situ preservation was feasible three campaigns were carried out. This led to the conclusion that the burial conditions were excellent and there was little risk that severe degradation will reduce archaeological information of the site over the coming decades. The remaining threat concerned illegal excavators with metal detectors and spades. To protect the site it was covered with a series of different materials to prevent the site from being looted.

KEYWORDS: heritage management, Early Medieval period, Merovingian, conservation, roman villa, burial ground, inhumations, bone, post-depositional processes, soil conditions

Introduction Archaeological sites face different kinds of threats. The features and artefacts are sub- ject to degradation caused by physical processes (e.g. ploughing, erosion) and chemical deterioration (e.g. oxidation, corrosion). Another threat is removal of objects by treasure hunters. Robbery and theft of valuable archaeological remains has occurred throughout history. Especially, burial gifts are at risk as they are often found concentrated at known spots. Since the development of the metal detector, the amount of metal objects taken from known archaeological sites, despite legislation, has grown enormously. Although the cooperation between metal detector hobbyists and archaeologists is generally very friendly, some tend to have a more pirate-like approach. In Borgharen, municipality of

© 2016 Informa UK Limited, trading as Taylor & Francis Group DOI 10.1080/13505033.2016.1182766 322 J. WILLEM DE KORT, et al.

Maastricht, the Netherlands, an early medieval burial site has been partly excavated in recent decades. During one of those excavations robbers stole newly discovered objects from several graves, despite a metal detection prohibition, a metal fence around the excavation, and daily covering of the graves that were being excavated. As the rest of the site being preserved in situ, the Cultural Heritage Agency of the Netherlands decided to take measures to prevent further looting of the site.

The site In the second century ad a Roman villa stood beside the . The farm, partially stone-built, had underfloor heating and walls covered with painted plasterwork. After the villa fell into disuse and the site had largely been cleared, it served as a burial ground in the sixth and seventh centuries. This unique combination of villa and burial ground was discovered during a trial trench survey. The archaeological investigation was prompted by planned major infrastructure works to give the River Meuse more room in order to prevent major flooding as seen in the 1990s. The unique combination of functions at a single site led to its being listed as an archaeological monument, with the aim of pre- serving the archaeological remains in situ.

In situ preservation as a problem As luck would have it, the developer at Borgharen — the public works agency Rijkswaterstaat — was prepared to adapt its plans so that the monument could be pre- served in situ. However, the preliminary investigation in 1999 also found that the human bone material at the burial ground was in a poor state of preservation and that, given the local burial conditions; it would only deteriorate — as would the state of the iron — and that no measures could be taken at the site to halt this process (Hulst & Dijkman, 2008). This led to a peculiarly conflicting set of circumstances: an initiator who is willing to facilitate in situ preservation, combined with the certainty that in time bone and iron artefacts would be lost. An additional problem lay in the fact that the initiator could no longer be ordered to pay the costs of any excavation under the ‘developer pays’ principle. In response to this problem, it was decided to preserve in situ what could be preserved in situ and to secure anything that would otherwise be lost due to degradation by investigating it. Research into the feasibility of in situ protection was performed during a number of campaigns spread over several years, so that the research strategy and procedures could be adapted on progressive insight and evaluation of previous years’ results. In order to derive maximum benefit from the expertise of thirty-one researchers, the science spe- cialists collaborated as directly as possible with more ‘traditional’ archaeologists. This synthesis resulted in a joint project between several researchers and authors (Lauwerier, et al., 2011b; Lauwerier & de Kort, 2014).

Burial ground and buried people During the series of investigations, a total of twenty-four human graves and two horse graves were identified (Figure 1). Fifteen of the human burials were excavated: eight during the archaeological field evaluation by Maastricht Council in 1995 and 1999 (Hulst Protection of a Merovingian Burial Ground in Borgharen 323

f6

24 f16 11 13 5 12 9

6 7 8 3 4 10 2 16 1 17 22 18 19 14 20 15 21

23

0 10m

Research 1995 and 1999 Inhumation (grave number) (Possible) Roman Research 2008, 2009 and 2012 Horsegrave (feature number)

FIGURE 1 Overview of the Merovingian graves of people and horses and the (possible) Roman features found during the sequence of excavations. Insert: location of Borgharen-Pasestraat (Maastricht municipality), the Netherlands. Map and drawing by RCE

& Dijkman, 2008) and seven during the 2009–12 campaigns (Lauwerier, et al., 2011 and Lauwerier & de Kort, 2014). Nine graves are still in situ. The graves are all oriented northeast-southwest. There is great diversity in the burials. Some graves are near the current surface, while others lie over a metre deep. Some graves contain numerous objects that were buried with the individual, while others contain only a few (Figure 2). The graves of men and women are more or less equal in number. Their ages range from young children to individuals in their fifties (Panhuysen 2011; 2014). Some graves contain more than one person. 324 J. WILLEM DE KORT, et al.

FIGURE 2 Finds: wooden buckets with bronze dish (restored), iron stirrups inlaid with brass. Photographs by Restaura

Degradation research and future development The condition of the human bone material recovered at the site varies enormously (Figure 3). Some has visibly deteriorated and is physically weak. Other bones are well preserved and physically stronger. Furthermore, DNA in teeth was found to be generally well pre- served, despite individual differences. The soil contains lime and is fairly impermeable to water: good conditions for the preservation of bone (Huisman, et al., 2011). We concur with the conclusions drawn from the research in 1993 and 1995, that human bone at the site was still degrading, and the situation could not be corrected. To determine the real reason for the poor condition of some of the material, it was subjected to histological analysis (Huisman, et al., 2011; Lauwerier, et al., in prep.). The results showed that though the surface of the human bone was damaged, the rest of the histology of the bone was intact and well preserved. The degradation of the surface is mainly the result of bacterial damage, and the bacteria must have come from the body itself, in the degradation process that occurs shortly after burial, as the body disintegrates, and before the burial chamber and coffin have collapsed and filled with sediment. The conclusion of our investigation was that the degradation occurred in the period shortly after burial. This of course raises the question of why some human bone is better preserved in the vicinity of Borgharen (e.g. the Merovingian burial site at Boschstraat; Panhuysen, 2005). As a final test, some well-preserved bones of intrusive animals (moles and foxes) from the fill in the graves were14 C-dated. Some of the bones looked almost fresh, and could in fact have been sub-recent intruders (and actors of bioturbation). The results did however show that these well-preserved bones are not recent, but come from more or less the same period as the burial ground, or even earlier (Lauwerier & Laarman, 2011). The overall conclusion was therefore that there is little risk that severe degradation will reduce the information value of the site over the coming decades. This also removed the need to excavate the burial ground in the next few years, as in situ preservation is in fact perfectly possible, contrary to what was initially assumed. And since in situ preservation is the policy of the Cultural Heritage Agency, the decision was made not to conduct any Protection of a Merovingian Burial Ground in Borgharen 325

FIGURE 3 On the left: well preserved; and on the right: poorly preserved skeletal remains. Photographs (left) by RCE, (right) Municipaly of Maastricht further excavations, and to leave the site to later archaeologists with new questions and new techniques.

Protection of the site The only acute threat to the site was looting by treasure hunters with metal detectors and spades and, to a lesser extent, bioturbation by plant roots. A change in land use, from agriculture towards a nature reserve gave us the opportunity to protect the site. First, the site was covered with an anti-root membrane, to prevent roots damaging features and to diminish bioturbation (Figure 4). To hinder metal detection, a 3.1 mm thick layer of plas- ticized chain-link fencing with a 2.0 mm galvanized steel centre and a mesh size of 50 mm was laid over this. Finally, a layer of 40–50 cm gravel was applied. This further raised the site, emphasizing the burial ground, perfectly fitting the wider landscape as a wildlife conservation area. Hopefully, although this is known as a ‘rich’ site, these measures will be adequate to protect it from future theft and loss of archaeological information. This programme was funded by TOPsites (http://cultureelerfgoed.nl/dossiers/verbeter- acties-archeologie/topsites), a project that was started after the evaluation of the Valletta Agreement for improving heritage policies (Council of Europe, 1992). The mission of 326 J. WILLEM DE KORT, et al.

FIGURE 4 The covering of the site in progress. Photograph by RCE.

TOPsites is to improve the conservation of archaeological sites by determination and subsequent mitigation of the most important degradation processes.

ORCID Bertil van Os http://orcid.org/0000-0003-1739-1696

References

Council of Europe. 1992. European Convention on the Protection of the Archaeological Heritage (revised) (Valletta 1992). Council of Europe Treaty Series no. 143. [online] [accessed 1 December 2015]. Available at: Huisman, D.J., van Os, B.J.H. & Jans, M.M.E. 2011. Resultaten degradatieonderzoek. In: R.C.G.M. Lauwerier, A. Müller and D.E. Smal, eds. Merovingers in een villa. Romeinse villa en Merovingisch grafveld Borgharen- Pasestraat. Onderzoek 2008–2009. Rapportage Archeologische Monumentenzorg 189 [Results degradation research: In: R.C.G.M. LauwerierA. Müller and D.E. Smal, eds.A Merovingean Villa: A Roman villa and Merovingean burial site at Borgharen:Pasestraat (Maastricht area) Excavation 2008-2009. Archaeological heritage report 189]. Amersfoort: Cultural Heritage Agency, pp. 39–44. Hulst, R.A. & Dijkman, W. 2008. Aanvullend archeologisch onderzoek Borgharen-Pasestraat (gem. Maastricht) [Archaeological research Borgharen-Pasestraat follow up. (Maastricht area)]. Maastricht: Maastricht Council. Lauwerier, R.C.G.M. & de Kort, J.W. 2014, eds. Merovingers in een villa 2. Romeinse villa en Merovingisch grafveld Borgharen-Pasestraat. Onderzoek 2012. In: Rapportage Archeologische Monumentenzorg 222 [A Merovingean Villa part 2: A Roman villa and Merovingean burial site at Borgharen:Pasestraat (Maastricht area) Excavation 2012. Archaeological heritage report 222]. Amersfoort: Cultural Heritage Agency. Lauwerier, R.C.G.M. & Laarman, F.J. 2011. Dierlijk materiaal. In: R.C.G.M. Lauwerier, A. Müller and D.E. Smal, eds. Merovingers in een villa. Romeinse villa en Merovingisch grafveld Borgharen-Pasestraat. Onderzoek 2008–2009. Rapportage Archeologische Monumentenzorg 189 [Animal remains. In: A Merovingean Villa: A Roman villa and Protection of a Merovingian Burial Ground in Borgharen 327

Merovingean burial site at Borgharen:Pasestraat (Maastricht area) Excavation 2008-2009. Archaeological heritage report 189]. Amersfoort: Cultural Heritage Agency, pp. 111–121. Lauwerier, R.C.G.M., Müller, A. & Smal D.E. 2011, eds. Merovingers in een villa. Romeinse villa en Merovingisch grafveld Borgharen-Pasestraat. Onderzoek 2008–2009. In: Rapportage Archeologische Monumentenzorg 189 [A Merovingean Villa: A Roman villa and Merovingean burial site at Borgharen:Pasestraat (Maastricht area) Excavation 2008-2009. Archaeological heritage report 189]. Amersfoort: Cultural Heritage Agency. Lauwerier, R.C.G.M., De Kort, J.W., Huisman, M.M.E., van de Jagt, D.J., Jans, I.M.M., van Os, B.J.H. & Panhuysen, R.G.A.M. in prep. Assessment of archaeological information loss of a Merovingian burial site; An integrated study to the degradation of human remains by combining archaeological, histological, DNA, 14C and geochemical information from different find categories and the burial environment. Panhuysen, R.G.A.M. 2005. Demography and Health in Early Medieval Maastricht: Prosopographical Observations on two Cemeteries. PhD thesis, , Amersfoort. Panhuysen, R.G.A.M. 2011. Menselijke resten (macroscopisch). In: R.C.G.M. Lauwerier, A. Müller and D.E. Smal, eds. Merovingers in een villa. Romeinse villa en Merovingisch grafveld Borgharen-Pasestraat. Onderzoek 2008–2009. Rapportage Archeologische Monumentenzorg 189. Amersfoort: Cultural Heritage Agency, pp. 83–84. Panhuysen, R.G.A.M. 2014. Menselijke resten (macroscopisch). In: R.C.G.M. Lauwerier and J.W. de Kort, eds. Merovingers in een villa 2. Romeinse villa en Merovingisch grafveld Borgharen-Pasestraat. Onderzoek 2012. Rapportage Archeologische Monumentenzorg 222 [Human Remains. In: R.C.G.M. Lauwerier, A. Müller and D.E. Smal eds. A Merovingean Villa 2: A Roman villa and Merovingean burial site at Borgharen:Pasestraat (Maastricht area) Excavation 2012. Archaeological heritage report 222]. Amersfoort: Cultural Heritage Agency, pp. 97–104.

Notes on contributors Bertil van Os is a researcher at the Cultural Heritage Agency, where he works with the in situ preservation of archaeological remains. His research is focused on wetlands, built environments and degradation of cultural heritage in general. Correspondence to: Bertil van Os. Email: [email protected] Jan Willem de Kort is working at the Cultural Heritage Agency as a field archaeologist. He is specialized in Pleistocene sites and archaeobotanical research. Roel Lauwerier is working at the Cultural Heritage Agency as an archaeozoologist. He is programme leader for the implementation of Malta Legislation in the Netherlands. Cees van Rooijen is archaeological advisor at the Cultural Heritage Agency and project leader for the TOPsites project.

View publication stats