ARCHAEOLOGICAL METHOD FEHMARN STYLE

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1 ARCHAEOLOGICAL METHOD FEHMARN STYLE Digital archaeology By: Nadja M. K. Mortensen, Prehistoric Archaeologist, Responsible for GIS Overview of the survey area Digital measuring and registration are an important part of Museum Lolland-Falster's fixed procedure in connection with archaeological excavations. Digital measuring ensures not only a precise registration of archaeological surveys, but also a raising of awareness of in situ ancient monuments for posterity. As shown below, digital registrations can also prove decisive for the planning of archaeological surveys. At the Fehmarn Belt excavations, everything from excavation areas and trial trenches to drilling samples, structures and artefacts are measured by means of GPS or a total station. Preliminary investigations, Phase 1 Investigation method In May 2012, Museum Lolland-Falster began the first phase of the archaeological preliminary investigation in connection with the construction of an immersed tunnel under the Fehmarn Belt. During the investigation, the museum carried out 987 core drillings with a diameter of 70 mm each. The drillings were made in collaboration with Dutch contractors Sialtech, and they were done because the preliminary investigation could not be conducted by traditional means. For archaeological preliminary excavations, you would normally establish so-called trial trenches. These are two metres wide and will be laid out at approx. 15-metre intervals distributed across the area that is relevant for the investigation. However, considering that 187 hectares of the area around Rødbyhavn are made up of reclaimed seabed, it was not possible to conduct a traditional preliminary investigation. A trial carried out in the autumn of 2011 showed that the water pressure from the Fehmarn Belt is so strong that the ground-

2 Overview of core drillings water level is so high that without sheet-piling, the sides of the trenches would collapse, and the trenches would very quickly be flooded. As one of the most low-lying countries in the world, the Netherlands faces the same problem. They have therefore developed a preliminary investigation method that does not consist of the traditional trial trenches, but of core drillings. this method in Rødbyhavn, and to supplement with auger drillings and small sheet-piled areas. Before the drillings took place, they were all marked out using GPS and a total station in a systematic grid to ensure that the drillings were carried out in exactly the right places, and in order to cover as wide a section of the area as possible. Based on the Netherlands' positive experience with this type of investigation of reclaimed areas, it was decided together with Femern A/S to apply The geological model The results of the core drilling samples have made it possible to make a stratigraphic analysis of the sediment layers in the area. All of the drilling sam- Sialtech have carried out a drilling and are running the drilling core, the soil column, out from the drill. To the right in the photo, an archaeologist examines a part of such a soil column. Measuring by means of a total station (to the left in the photo) and GPS (to the right in the photo)

3 Geology at three metres' depth ples and the different layers were registered in a database, and based on the defined drilling samples and the database, the museum has developed a digital geological landscape model of the area. The model illustrates the geology at e.g. two or three metres' depth below the current sea level, showing the position of sand, clay, peat or gyttja in relation to each other. The model can thus help provide knowledge of where there would have been water, and where there would have been land at different times in prehistory. This gives us information about what the area looked like, and how it has developed through the ages. Even before the preliminary investigation began, we were aware that originally, there was a fjord facing the Fehmarn Belt, stretching right up to Rødby, approx. 5 km from the current coastline. Our geological model also shows that there were two small lagoons with appertaining barrier islands to the east of the current ferry terminal. Scientific investigations Samples were taken from a wide selection of the core drillings for salinity analyses. A salinity analysis shows the salt content in the samples, and this makes it possible to study where there would have been seawater, brackish water and freshwater, respectively. Like the geological landscape model, The two lagoons east of Rødby Harbour this can help shed light on what the lagoons looked like, and where it would have been advantageous to settle in relation to the access to drinking water and fishing possibilities. In addition to samples for salinity analyses, samples were taken for radiocarbon dating. This dating makes it possible to date the different layers, and the layers can then reveal the age of any artefacts and structures. Preliminary investigations, Phase 2 The geological landscape model has been crucial for our continued investigations in the Fehmarn Belt

4 Overview of auger drillings project, as the investigation strategy is based on this to a great extent. Throughout Danish prehistory, man has preferred to settle near water. However, particularly towards the end of the Mesolithic Age, the fjords were the preferred places for settlements. Either by the fjord estuaries or inside the fjords along the coasts. Considering this knowledge, and based on the geological landscape model, the museum has selected the most obvious places, i.e. the areas in which it is most likely that traces of Stone Age settlements can be found. Investigation method Phase 2 of the preliminary investigation stretched from December 2012 to March During this period, the museum collaborated with the contractors MSE A/S, carrying out 1,119 auger drillings with a diameter of 120 cm each. Before drilling started, the auger drillings were marked off using GPS, and their positions were selected carefully based on the geological landscape model and the knowledge we have about the location of Stone Age settlements. The objective of the auger drillings was to find archaeological artefacts and thus to trace archaeological localities. All artefacts found have subsequently been related to specific stratigraphic sediment layers, MSE have made a mechanical auger drilling, and an archaeologist is examining the soil for artefacts. Distribution of artefacts from the auger drilling samples. The red columns illustrate the number of artefacts found.

5 Overview of sheet-piled boxes but apart from this, no further emphasis was placed on the stratigraphic layers during this preliminary investigation phase. All artefacts were also registered in a database where they have been related to the auger drillings in which they were found. The database has subsequently been transferred to a map. This has made it possible to make a map showing the distribution of artefacts across auger drillings. Preliminary investigations, Phase 2.1 Investigation method As the final part of the preliminary investigation, from March 2013 to June 2013, 64 sheet-piled boxes measuring 4 x 4 metres each were set up. The engineering company Arkil A/S handled the sheet-piling of the boxes, while the museum in collaboration with MSE A/S handled the excavation and examination of the boxes. The boxes were placed in the areas where the auger drillings had shown most artefacts, in the hope that these were indications of settlements or other human activity areas. The expectations about the excavation of the boxes were high from the outset. Suddenly, it was also possible to register any structures such as fireplaces, huts, graves and in situ fishing structures due to the larger survey areas, and not just individual artefacts such as flint axes, arrowheads, pottery and animal bones. Sheet-piling of a 4 x 4-metre box The vast majority of the boxes contained artefacts, and several boxes showed signs of containing structures. Among these was a well-preserved fish fence, which stands as it was left approx. 5,000 years ago. The extraordinary preservation conditions have also led to finds of animal bones, bone needles and sharpened stakes, which look as if they were made yesterday. So far, we have not found any human bones, but

6 The first actual excavation we hope to find Stone Age graves in the area. In order to document the full extent of the surveys, all of the boxes were measured using GPS or a total station after the sheet-piling. Furthermore, any structures and systems of upright and/or horizontal sticks were measured. All structures were also drawn and photographed. Wherever this was possible, a section of the boxes upright wall was also drawn and photographed in order to document the different soil layers and their thickness. Just as in the case of the auger drillings, all artefacts from the boxes were entered into a database, which was subsequently transferred to a map. Scientific investigations As in the case of the core drillings, samples were taken, both from soil and from sharpened sticks and animal bones to be submitted for radiocarbon dating, which will enable us to date our finds. The radiocarbon dating from the boxes supports our theory that the area was inhabited at the end of the Mesolithic Age and during the Neolithic Age. The final excavations Based on the overall results from the preliminary investigation, 30 areas have been selected, which are of particular archaeological interest. Within these areas, smaller areas have been appointed for actual excavation. The first excavation started in the eastern part of the area in mid-august 2013, and was completed mid-september The selection of areas for excavation has been given a lot of consideration based on the results of our preliminary investigations. We know from the preliminary investigations that there are traces of activity from the end of the Mesolithic and the Neolithic. However, as of yet, we do not have a complete understanding of the extent of this activity. It is difficult to predict what the final results will be, but in the archaeological team at Museum LollandFalster, we can t wait to find out! Fish fence