An exploratory use of 3D for investigating a Prehistoric stratigraphic sequence
Giacomo Landeschi, Jan Apel, Stefan Lindgren, Nicolò Dell'Unto
Abstract Re-interpreting documentation that has been produced in the course of an archaeological excavation is always a challenging and tricky task. Several problems occur when archaeologists are dealing with datasets created by different authors at a different time in the past. As Shanks and Tilley recall (1992) the fullest understanding of an archaeological dataset is totally related to the context being investigated. The purpose of a research recently started at Lund University was to test the use of 3D technology as an exploratory tool for data analysis. The combination of advanced 3D acquiring techniques and the setup of GIS systems capable to deal with geometrically-complex 3D information has been tested to investigate one of the most outstanding archaeological sites in Scandinavia, the cave of Stora Förvar in Stora Karlsö, Gotland (Sweden). The main part of the cave sequence was excavated between 1888 and 1894 but in the summer of 2013 the project conducted a small excavation of the cave floor and undisturbed cultural layers with flint tools, fish and marine mammal bones were recovered. We also recovered human remains in the form of a tooth, skull fragments and a foot bone. Unfortunately the original field report of the 19th-century excavation was written 50 years after the excavation by archaeologists not involved in the field work. However, unpublished photos and field documentation material is available at Antikvarisk Topografiska Arkivet in Stockholm. During the excavation in 2013 we collaborated with the Lund University Humanities Laboratory and 3D-scanned the complete cave with a high resolution scanner. The idea that has been developed was to integrate the 3D models of the cave in the GIS platform and to combine it with hand-made drawings made by archaeologists in the early 20th century. As a result, digital layers (that were excavated with the arbitrary layer method) were reconstructed in the form of three-dimensional vector features and the original stratigraphic sequence integrated in GIS based on the geometrical reference provided by the cave 3D model. As a future development, part of the artefacts documented during the early 20th Century excavation will be connected to their original stratigraphy. Hopefully, it will be possible to recreate a three-dimensional archaeological sequence in which the original spatial relations among the artifacts will be highlighted and possible patterns related to the Mesolithic occupation of the site put in light through the use of advanced analytic tools available in GIS environment.
