My research is focused on the use of archaeological geophysical prospection methods in Swedish archaeology. Geophysical methods commonly used for archaeological projects include for example. magnetometry, electrical archaeological geophysics has been used successfully for several decades in many other countries the methods have resistance or resistivity, ground-penetrating radar, magnetic susceptibility, electrical conductivity etc. Even though only been used sporadically in Sweden. The only geophysical instrument that seems to have become very popular among Swedish archaeologists is the metal detector.
I therefore wanted to investigate the reason for this underuse by looking at among other things the few surveys that have been carried out as well as to look into the general attitude among archaeologists towards the methods, as reflected in the different project reports produced after the initial evaluations. Factors such as geology and the nature of the Swedish archaeological record have also been taken into consideration. In addition to this I have performed several geophysical surveys on archaeological sites that chronologically span from the Neolithic to the Middle Ages and geographically span from the mountain tundra region in Lapland to Öland and Gotland in southern Sweden. The purpose of the surveys was to demonstrate both the pitfalls and possibilities of archaeological geophysics when deployed in different geographically and chronologically settings.
"The aim of this thesis has been to investigate the benefits, pitfalls and possibilities of using... more "The aim of this thesis has been to investigate the benefits, pitfalls and possibilities of using geophysical methods in archaeological projects. This is exemplified by surveys carried out at archaeological sites in different geographical and chronological contexts. The thesis also aims at investigating the cause for the under-use of the methods in Swedish archaeology by looking at previously conducted surveys. The methods used during these surveys have been Ground-penetrating radar (GPR), magnetometer, slingram and a kappameter. The surveys in the mountain tundra region of Lapland show that magnetic susceptibility surveys is a valuable aid in discovering heaps of fire-cracked stones and when combined with magnetometry, also hearths. GPR and magnetometer surveys within the Migration Period ringfort Sandbyborg provided the spatial layout of the fort and indicated, along with results from recent excavations and metal detections, many similarities with the ringfort Eketorp II. The non-magnetic character of the sedimentary bedrock on Öland and Gotland is suitable for magnetometer surveys and the method is also highly appropriate for the detection of the remains of high-temperature crafts. GPR surveys at St. Mary’s Dominican convent in Sigtuna produced the spatial layout of the central cloister area. The investigations also show that the geology, pedology, land use and the character of commonly occurring prehistoric remains in Sweden, in certain circumstances and in certain areas, have restricted the possibility of successfully carrying out geophysical surveys. Care must therefore be taken to choose the right instrument for the survey and to tailor the sampling density of each geophysical survey, according to the character and size of the expected archaeological remains, in order to maximize their information return. To increase the use of geophysical methods in Sweden the educational opportunities, both for surveyors and professional archaeologists, need to improve.
"
In August 2018, a group of experts working with terrestrial/marine geophysics and remote sensing ... more In August 2018, a group of experts working with terrestrial/marine geophysics and remote sensing methods to explore archaeological sites in Denmark, Finland, Norway, Scotland and Sweden gathered together for the first time at the Workshop 'Sensing Archaeology in The North'. The goal was to exchange experiences, discuss challenges, and consider future directions for further developing these methods and strategies for their use in archaeology. After the event, this special journal issue was arranged to publish papers that are based on the workshop presentations, but also to incorporate work that is produced by other researchers in the field. This paper closes the special issue and further aims to provide current state-of-the-art for the methods represented by the workshop. Here, we introduce the aspects that inspired the organisation of the meeting, a summary of the 12 presentations and eight paper contributions, as well as a discussion about the main outcomes of the workshop roundtables, including the production of two searchable databases (online resources and equipment). We conclude with the position that the 'North', together with its unique cultural heritage and thriving research community, is at the forefront of good practice in the application and development of sensing methods in archaeological research and management. However, further method development is required, so we claim the support of funding bodies to back research efforts based on testing/experimental studies to: explore unknown survey environments and identify optimal survey conditions, as well as to monitor the preservation of archaeological remains, especially those that are at risk. It is demonstrated that remote sensing and geophysics not only have an important role in the safeguarding of archaeological sites from development and within prehistorical-historical research, but the methods can be especially useful in recording and monitoring the increased impact of climate change on sites in the North.
As a part of the project "The Big Five", large-scale multi-channel ground-penetrating radar surve... more As a part of the project "The Big Five", large-scale multi-channel ground-penetrating radar surveys were carried out at Bårby ringfort (Swedish: borg), Öland, Sweden. The surveys were carried out using a MALÅ Imaging Radar Array (MIRA) system and aimed at mapping possible buried Iron Age and Medieval remains through the interior in order to better understand the purpose of the fort during its periods of use. An additional goal was to evaluate the impact of earlier farming on the preservation of the archaeological remains. The data provided clear evidence of well-preserved Iron Age and Medieval buildings inside the fort. The size and the pattern of the Iron Age houses suggest close similarities with, for example, the previously excavated fort at Eketorp on Öland. Given the presence of a substantial cultural layer together with a large number of artefacts recovered during a metal detection survey, it is suggested that Bårby borg's primary function during the Iron Age was as a fortified village. The Medieval houses partly cover some of the Iron Age buildings. They are placed in a U-shape with an open square in the middle facing the edge of a limestone cliff. As in the case of Eketorp, it is suggested that the activities during Medieval times changed, but the precise purpose of the Medieval Bårby settlement is still a question open for debate. Future targeted archaeological investigations are needed in order to better understand its purpose. Rescue excavations may also be necessary, as the western steep cliff ledge is eroding and the well-preserved archaeological remains are at risk of being destroyed.
The Archaeology of Death, Proceedings of the Seventh Conference of Italian Archaeology held at the National University of Ireland, Galway, April 16-18, 2016 (Papers in Italian Archaeology VII), eds. Edward Herring and Eóin O'Donoghue, Archaeopress, Oxford, 2018
This article presents the Stockholm Volterra Project and its development since 2013. This project... more This article presents the Stockholm Volterra Project and its development since 2013. This project, run by Stockholm University and the Department of Archaeology and Classical Studies, has carried out geophysical prospections in Volterra in collaboration with Soprintendenza Archeologia, Belle Arti e Paesaggio per le province di Pisa e Livorno. The aims and methods of the project are outlined together with a closer presentation of key sites from 2014 and 2015: the ‘Football Pitch’, the area in front of the church of San Giusto, the ruined church of Santo Stefano, the amphitheatre and Ortino sites.
In 2007 a magnetometer survey was carried out at the ring fort Gråborg on the Swedish island of Ö... more In 2007 a magnetometer survey was carried out at the ring fort Gråborg on the Swedish island of Öland. The results were interpreted as indicating the remains of over 60 buildings, several roads, wells and a large moat outside the fort's north western gate. In 2011 these interpretations were severely criticised, and it was suggested that the moatlike anomaly in the geophysical data had actually been caused by a lightning strike. It was also suggested that none of the other interpreted features were actually supported by the presented magnetometry data. This paper presents the results of a ground-penetrating radar (GPR) survey of the same area. The GPR data were collected in 2014 using the multi-antenna Malå Imaging Radar Array (MIRA) system, covering an area of approximately 3.8 ha. The results show that the ground inside and outside the fort's walls is heavily disturbed by farming. Most of the underground features visible in the data can be interpreted as drainage ditches and power cables, but a few linear features are identified as being of possible archaeological interest. When comparing the radar data to the buildings, roads and wells suggested in the magnetometry interpretation, no apparent correlation can be established. There is furthermore no sign of any moat in the suggested area. The GPR results therefore support the idea that this moat like feature is indeed the remains of a lightning strike.
Mycket tyder på att den storgård som har hittats på Björkö har tillhört kungens fogde Hergeir, ha... more Mycket tyder på att den storgård som har hittats på Björkö har tillhört kungens fogde Hergeir, han som kristnades av Ansgar. Ytterligare fynd tyder på en föregångare till gården.
In September 2016 geophysical surveys were conducted at Korshamn, as one of the main harbour bays... more In September 2016 geophysical surveys were conducted at Korshamn, as one of the main harbour bays of the island of Björkö, situated outside the town boundaries of the Viking town of Birka. The investigation of a solitarily raised plateau at Erik Steffanssons hemland revealed the outline of a large Vendel-period house. Together with further anomalies at a one-sided terrace at Kalvhagen a whole manor complex might be seizable predating the Viking-age settlement activities on the island. The latter dwelling is superimposed by a major Viking-age hall connecting to a »fenced special area« as known from e. g. Lejre and Tissø and linked to cult activities. Both the structures and the chronological depth correlate well with the »ancestral property« of Birka’s royal bailiff Herigar as mentioned in Rimbert’s Vita Anskarii. If this assumption is correct even the whereabouts of Scandinavia’s first church should be located in the immediate vicinity. The consequences of this identification cannot be overestimated: In terms of the emergence of the Viking town, its royal administration and the earliest Christian mission to Scandinavia.
In October 2014 georadar surveys were carried out on four different sites in Sigtuna in order to ... more In October 2014 georadar surveys were carried out on four different sites in Sigtuna in order to detect possible harbour features of Viking and early medieval date. The sites chosen were Urmakaren, Borgmästarängen, Draken and Koppardosan, all of which are situated either close to or directly on the Viking-Age shoreline. Georadar, new to harbour research in Sigtuna, has the potential of offering a new dimension to the on-going debate. Whilst the data gathered from Urmakaren and Borgmästarängen failed to provide any indication of harbour-related features, the results from Koppardosan and Draken proved to be of interest, providing distribution patterns that could derive from jetties of various sizes. Contemporary archaeological finds support the possibility of a harbour area in the proximity of the investigated sites and further to the east. Thus the obtained georadar data should be validated through excavation and additional surveys should be carried out on other sites in Sigtuna.
This article aims at providing evidence for the usefulness of combining data from both above and ... more This article aims at providing evidence for the usefulness of combining data from both above and below the ground in order to provide a more complete understanding of an archaeological site. For this purpose a Ground-penetrating radar (GPR) survey was carried out next to the standing ruins of the west tower of the church of St. Lawrence in Sigtuna, Sweden. The tower ruins were also documented using photogrammetry providing an accurate 3D-model of the site. The result of the GPR survey clearly images the buried wall foundations of the church but it is only when this data is combined with the photogrammetric 3D-model of the tower ruins that the spatial layout becomes complete. The results clearly provide evidence of the benefits of using such an integrated approach. The available evidence suggests that the tower, nave and choir (with a possible apse) were constructed during the 12th century. During the 15th century the church porch was built and arches added to the nave. The building history of the church is thus rather ordinary compared to other contemporary Swedish churches and, as a consequence, it is likely that that the church was built for the city congregation.
Aska hamlet in Hagebyhöga parish, Östergötland (Sweden), is famous among Viking scholars for a ri... more Aska hamlet in Hagebyhöga parish, Östergötland (Sweden), is famous among Viking scholars for a rich female burial under a low cairn that was excavated in 1920. The main visible archaeological feature of the site is an enormous barrow, but its contents have not been excavated. As the barrow is oval and has an extensive flat top, it has been hypothesized previously that rather than a grave superstructure, this might be an uncommonly large raised foundation for a long house. We occasionally see this type of feature at elite manorial sites from the period ad 400–1100. We have tested this idea at Aska with ground-penetrating radar, securing the clear and detailed floor plan of a post-supported hall building almost 50 m long. Its closest known architectural parallel, also sitting on a similar platform, has been excavated at Old Uppsala, the late first millennium ad political and ceremonial centre of the ancient Swedes. At Aska, it appears that we have found another such real-world correlate of the Beowulf poem's royal mead-hall Heorot, but in this case located in a smaller and less powerful polity. This all suggests a petty royal status for the owners of the Aska hall, who enjoyed connections with Scandinavia's top political elite.
Archaeological investigations and clear aerial photos have identified the presence of house found... more Archaeological investigations and clear aerial photos have identified the presence of house foundations within several
ringforts on the island of Öland, east of the Swedish mainland. One of them, Sandby borg, was selected for further investigations by means of a ground-penetrating radar (GRP) and magnetometry survey. A subsequent excavation was carried out to validate the geophysical results. The results of the geophysical survey clearly show the presence of 36 or 37 stone foundations for houses situated radially around the wall of the fort as well as of 16 or 17 similar house foundations in a central building group. The geophysical results also provided information on other buried features within the fort and also confirm the location of a third gate situated in the north-western part of the fort. The available evidence indicates that the ringfort was used for military purposes, or as a place of refuge in times of unrest, for a limited period of time during the late 5th century.
""During the summer of 2008 archaeological excavations and geophysical prospection surveys were c... more ""During the summer of 2008 archaeological excavations and geophysical prospection surveys were carried out in the mountain
tundra region of north-eastern Sweden. The investigations focused on locating settlement remains connected with a Middle
Neolithic tool production site discovered by archaeologists in 2001.
Magnetic susceptibility surveys using the MS2D system by Bartington Instruments and an EM38 by Geonics measuring the
Inphase component of the electromagnetic field were used for the prospection of measureable traces of anthropogenic activity
and structures such as hearths and middens within the estimated settlement area. Soil samples for phosphate analysis were
also collected and analysed using a field analysis method developed by Merck.
The magnetic susceptibility measurements successfully located a waste heap containing fire-cracked stones and refuse from a
seasonal settlement. The results of the survey were confirmed by subsequent archaeological excavations, which also revealed
a piece of resin with the imprint of a human tooth. One additional piece of resin dated the site to 3340 to 3100 BC. The soil
phosphate analysis showed slightly increased values over the central part of the site and over the heap of fire-cracked stones.
Comparison between the MS2D and EM38 measurements revealed a weak impact of the bedrock on the results, indicating a
potential for the applicability of magnetic surveys to this specific type of environment. Future geophysical archaeological
prospection in the Swedish mountain tundra region could benefit from a combined approach using high-resolution
magnetometry and magnetic susceptibility measurements.""
Gradiometer surveys have been carried at three Iron Age and early medieval sites on the island of... more Gradiometer surveys have been carried at three Iron Age and early medieval sites on the island of Gotland, Sweden. Previous experiences of poorly executed magnetic surveys combined with a misconception among archaeologists that the Gotlandic sedimentary bedrock would preclude the success of any magnetic investigations on the island have, until now, prevented the extended use of the method within archaeological projects. The purpose of the present study was to test this presumption while searching for in situ buried remains of high-temperature crafts, such as metal and glass working. The location of the survey grids was guided by concentrations of previously recovered high-temperature craft finds from metal detector surveys and excavations. The results indicate that the magnetometer is a valuable tool for detecting the presence of preserved high-temperature craft structures in the Gotlandic soil. An additional result indicates that in this area the magnetometer can easily identify remains of ploughed-over Iron Age stone foundation houses and stone boundary walls. This is possible because of the prehistoric population's preference of using glacially deposited, igneous rocks in such constructions. It can thus be concluded that the uniformly non-magnetic character of the Gotlandic bedrock provides excellent conditions for conducting magnetic surveys.
A ground-penetrating radar (GPR) survey and an archaeological excavation of the buried remains of... more A ground-penetrating radar (GPR) survey and an archaeological excavation of the buried remains of the Medieval Dominican convent in Sigtuna (Raä 30) produced new information on the ground plan of the convent and the condition of the buried structures remaining at the site.The site has hitherto seen surprisingly little archaeological investigations, and it is now over 30 years since the previous fieldwork. In addition to the foundation walls of the convent and adjoining structures, GPR also revealed an earlier building phase and a previously unknown lavatorium connected to the southern range. These interpretations were confirmed by excavations in September 2009. A suggestion as to the function of the various buildings, based on comparison with other convents, is offered.
While geophysical prospection for iron ores has a long history in Sweden the use of geophysical a... more While geophysical prospection for iron ores has a long history in Sweden the use of geophysical archaeological prospection has been limited compared to other countries. In this paper we discuss the likely reasons for this situation and present a brief history of geophysical prospection and in particular geophysical archaeological prospection in Sweden. The first use of different prospection methods, such as metal detection, earth resistance, magnetic, ground-penetrating radar, seismic and electro-magnetic prospection in Swedish archaeology are presented. The archaeological Iron Age sites of Uppåkra and Birka have been subject to relatively intensive prospection activity and are therefore mentioned separately. An overview of the current situation of geophysical archaeological prospection and related issues is given, and pitfalls and possibilities are discussed. The paper finishes with an outlook on possible future developments.
Projektet Nordliga vapenhus i Uppland genomfördes under hösten 2009 i syfte att med hjälpa av en ... more Projektet Nordliga vapenhus i Uppland genomfördes under hösten 2009 i syfte att med hjälpa av en georadarutrustning belägga förekomsten av nordliga vapenhus vid tre Uppländska kyrkor i Alunda, Tierp och Bälinge. Georadarresulten visar på ett tydligt nordligt vapenhus vid ...
During May 2014 four prehistoric ring-forts on the island of Öland, namely Gråborg, Vedby borg, B... more During May 2014 four prehistoric ring-forts on the island of Öland, namely Gråborg, Vedby borg, Bårby borg and Löts borg, have been surveyed using a motorized Ground-Penetrating Radar (GPR) system. The surveys were carried out as a part of the project “The big five”, and included high-resolution GPR data collection covering in total approximately 7.5 ha of land inside the forts. As a complement to the geophysical survey the remaining walls and surroundings of Gråborg and Vedby borg were surveyed with a Mobile Mapping System (MMS) named GeoTracker.
Determining whether a magnetic anomaly detected at an archaeological site has a natural or a cult... more Determining whether a magnetic anomaly detected at an archaeological site has a natural or a cultural source can be quite challenging in some regions of the world because of magnetic variability related to soil development and differing rock/parent material types. Though not consistently recognized, lightning is one major source for magnetic anomalies on archaeological sites that often has been overlooked and misinterpreted. A case study from the High Bank Works in south-central Ohio, USA shows the range of strike anomaly sizes, shapes, and intensities.
"The aim of this thesis has been to investigate the benefits, pitfalls and possibilities of using... more "The aim of this thesis has been to investigate the benefits, pitfalls and possibilities of using geophysical methods in archaeological projects. This is exemplified by surveys carried out at archaeological sites in different geographical and chronological contexts. The thesis also aims at investigating the cause for the under-use of the methods in Swedish archaeology by looking at previously conducted surveys. The methods used during these surveys have been Ground-penetrating radar (GPR), magnetometer, slingram and a kappameter. The surveys in the mountain tundra region of Lapland show that magnetic susceptibility surveys is a valuable aid in discovering heaps of fire-cracked stones and when combined with magnetometry, also hearths. GPR and magnetometer surveys within the Migration Period ringfort Sandbyborg provided the spatial layout of the fort and indicated, along with results from recent excavations and metal detections, many similarities with the ringfort Eketorp II. The non-magnetic character of the sedimentary bedrock on Öland and Gotland is suitable for magnetometer surveys and the method is also highly appropriate for the detection of the remains of high-temperature crafts. GPR surveys at St. Mary’s Dominican convent in Sigtuna produced the spatial layout of the central cloister area. The investigations also show that the geology, pedology, land use and the character of commonly occurring prehistoric remains in Sweden, in certain circumstances and in certain areas, have restricted the possibility of successfully carrying out geophysical surveys. Care must therefore be taken to choose the right instrument for the survey and to tailor the sampling density of each geophysical survey, according to the character and size of the expected archaeological remains, in order to maximize their information return. To increase the use of geophysical methods in Sweden the educational opportunities, both for surveyors and professional archaeologists, need to improve.
"
In August 2018, a group of experts working with terrestrial/marine geophysics and remote sensing ... more In August 2018, a group of experts working with terrestrial/marine geophysics and remote sensing methods to explore archaeological sites in Denmark, Finland, Norway, Scotland and Sweden gathered together for the first time at the Workshop 'Sensing Archaeology in The North'. The goal was to exchange experiences, discuss challenges, and consider future directions for further developing these methods and strategies for their use in archaeology. After the event, this special journal issue was arranged to publish papers that are based on the workshop presentations, but also to incorporate work that is produced by other researchers in the field. This paper closes the special issue and further aims to provide current state-of-the-art for the methods represented by the workshop. Here, we introduce the aspects that inspired the organisation of the meeting, a summary of the 12 presentations and eight paper contributions, as well as a discussion about the main outcomes of the workshop roundtables, including the production of two searchable databases (online resources and equipment). We conclude with the position that the 'North', together with its unique cultural heritage and thriving research community, is at the forefront of good practice in the application and development of sensing methods in archaeological research and management. However, further method development is required, so we claim the support of funding bodies to back research efforts based on testing/experimental studies to: explore unknown survey environments and identify optimal survey conditions, as well as to monitor the preservation of archaeological remains, especially those that are at risk. It is demonstrated that remote sensing and geophysics not only have an important role in the safeguarding of archaeological sites from development and within prehistorical-historical research, but the methods can be especially useful in recording and monitoring the increased impact of climate change on sites in the North.
As a part of the project "The Big Five", large-scale multi-channel ground-penetrating radar surve... more As a part of the project "The Big Five", large-scale multi-channel ground-penetrating radar surveys were carried out at Bårby ringfort (Swedish: borg), Öland, Sweden. The surveys were carried out using a MALÅ Imaging Radar Array (MIRA) system and aimed at mapping possible buried Iron Age and Medieval remains through the interior in order to better understand the purpose of the fort during its periods of use. An additional goal was to evaluate the impact of earlier farming on the preservation of the archaeological remains. The data provided clear evidence of well-preserved Iron Age and Medieval buildings inside the fort. The size and the pattern of the Iron Age houses suggest close similarities with, for example, the previously excavated fort at Eketorp on Öland. Given the presence of a substantial cultural layer together with a large number of artefacts recovered during a metal detection survey, it is suggested that Bårby borg's primary function during the Iron Age was as a fortified village. The Medieval houses partly cover some of the Iron Age buildings. They are placed in a U-shape with an open square in the middle facing the edge of a limestone cliff. As in the case of Eketorp, it is suggested that the activities during Medieval times changed, but the precise purpose of the Medieval Bårby settlement is still a question open for debate. Future targeted archaeological investigations are needed in order to better understand its purpose. Rescue excavations may also be necessary, as the western steep cliff ledge is eroding and the well-preserved archaeological remains are at risk of being destroyed.
The Archaeology of Death, Proceedings of the Seventh Conference of Italian Archaeology held at the National University of Ireland, Galway, April 16-18, 2016 (Papers in Italian Archaeology VII), eds. Edward Herring and Eóin O'Donoghue, Archaeopress, Oxford, 2018
This article presents the Stockholm Volterra Project and its development since 2013. This project... more This article presents the Stockholm Volterra Project and its development since 2013. This project, run by Stockholm University and the Department of Archaeology and Classical Studies, has carried out geophysical prospections in Volterra in collaboration with Soprintendenza Archeologia, Belle Arti e Paesaggio per le province di Pisa e Livorno. The aims and methods of the project are outlined together with a closer presentation of key sites from 2014 and 2015: the ‘Football Pitch’, the area in front of the church of San Giusto, the ruined church of Santo Stefano, the amphitheatre and Ortino sites.
In 2007 a magnetometer survey was carried out at the ring fort Gråborg on the Swedish island of Ö... more In 2007 a magnetometer survey was carried out at the ring fort Gråborg on the Swedish island of Öland. The results were interpreted as indicating the remains of over 60 buildings, several roads, wells and a large moat outside the fort's north western gate. In 2011 these interpretations were severely criticised, and it was suggested that the moatlike anomaly in the geophysical data had actually been caused by a lightning strike. It was also suggested that none of the other interpreted features were actually supported by the presented magnetometry data. This paper presents the results of a ground-penetrating radar (GPR) survey of the same area. The GPR data were collected in 2014 using the multi-antenna Malå Imaging Radar Array (MIRA) system, covering an area of approximately 3.8 ha. The results show that the ground inside and outside the fort's walls is heavily disturbed by farming. Most of the underground features visible in the data can be interpreted as drainage ditches and power cables, but a few linear features are identified as being of possible archaeological interest. When comparing the radar data to the buildings, roads and wells suggested in the magnetometry interpretation, no apparent correlation can be established. There is furthermore no sign of any moat in the suggested area. The GPR results therefore support the idea that this moat like feature is indeed the remains of a lightning strike.
Mycket tyder på att den storgård som har hittats på Björkö har tillhört kungens fogde Hergeir, ha... more Mycket tyder på att den storgård som har hittats på Björkö har tillhört kungens fogde Hergeir, han som kristnades av Ansgar. Ytterligare fynd tyder på en föregångare till gården.
In September 2016 geophysical surveys were conducted at Korshamn, as one of the main harbour bays... more In September 2016 geophysical surveys were conducted at Korshamn, as one of the main harbour bays of the island of Björkö, situated outside the town boundaries of the Viking town of Birka. The investigation of a solitarily raised plateau at Erik Steffanssons hemland revealed the outline of a large Vendel-period house. Together with further anomalies at a one-sided terrace at Kalvhagen a whole manor complex might be seizable predating the Viking-age settlement activities on the island. The latter dwelling is superimposed by a major Viking-age hall connecting to a »fenced special area« as known from e. g. Lejre and Tissø and linked to cult activities. Both the structures and the chronological depth correlate well with the »ancestral property« of Birka’s royal bailiff Herigar as mentioned in Rimbert’s Vita Anskarii. If this assumption is correct even the whereabouts of Scandinavia’s first church should be located in the immediate vicinity. The consequences of this identification cannot be overestimated: In terms of the emergence of the Viking town, its royal administration and the earliest Christian mission to Scandinavia.
In October 2014 georadar surveys were carried out on four different sites in Sigtuna in order to ... more In October 2014 georadar surveys were carried out on four different sites in Sigtuna in order to detect possible harbour features of Viking and early medieval date. The sites chosen were Urmakaren, Borgmästarängen, Draken and Koppardosan, all of which are situated either close to or directly on the Viking-Age shoreline. Georadar, new to harbour research in Sigtuna, has the potential of offering a new dimension to the on-going debate. Whilst the data gathered from Urmakaren and Borgmästarängen failed to provide any indication of harbour-related features, the results from Koppardosan and Draken proved to be of interest, providing distribution patterns that could derive from jetties of various sizes. Contemporary archaeological finds support the possibility of a harbour area in the proximity of the investigated sites and further to the east. Thus the obtained georadar data should be validated through excavation and additional surveys should be carried out on other sites in Sigtuna.
This article aims at providing evidence for the usefulness of combining data from both above and ... more This article aims at providing evidence for the usefulness of combining data from both above and below the ground in order to provide a more complete understanding of an archaeological site. For this purpose a Ground-penetrating radar (GPR) survey was carried out next to the standing ruins of the west tower of the church of St. Lawrence in Sigtuna, Sweden. The tower ruins were also documented using photogrammetry providing an accurate 3D-model of the site. The result of the GPR survey clearly images the buried wall foundations of the church but it is only when this data is combined with the photogrammetric 3D-model of the tower ruins that the spatial layout becomes complete. The results clearly provide evidence of the benefits of using such an integrated approach. The available evidence suggests that the tower, nave and choir (with a possible apse) were constructed during the 12th century. During the 15th century the church porch was built and arches added to the nave. The building history of the church is thus rather ordinary compared to other contemporary Swedish churches and, as a consequence, it is likely that that the church was built for the city congregation.
Aska hamlet in Hagebyhöga parish, Östergötland (Sweden), is famous among Viking scholars for a ri... more Aska hamlet in Hagebyhöga parish, Östergötland (Sweden), is famous among Viking scholars for a rich female burial under a low cairn that was excavated in 1920. The main visible archaeological feature of the site is an enormous barrow, but its contents have not been excavated. As the barrow is oval and has an extensive flat top, it has been hypothesized previously that rather than a grave superstructure, this might be an uncommonly large raised foundation for a long house. We occasionally see this type of feature at elite manorial sites from the period ad 400–1100. We have tested this idea at Aska with ground-penetrating radar, securing the clear and detailed floor plan of a post-supported hall building almost 50 m long. Its closest known architectural parallel, also sitting on a similar platform, has been excavated at Old Uppsala, the late first millennium ad political and ceremonial centre of the ancient Swedes. At Aska, it appears that we have found another such real-world correlate of the Beowulf poem's royal mead-hall Heorot, but in this case located in a smaller and less powerful polity. This all suggests a petty royal status for the owners of the Aska hall, who enjoyed connections with Scandinavia's top political elite.
Archaeological investigations and clear aerial photos have identified the presence of house found... more Archaeological investigations and clear aerial photos have identified the presence of house foundations within several
ringforts on the island of Öland, east of the Swedish mainland. One of them, Sandby borg, was selected for further investigations by means of a ground-penetrating radar (GRP) and magnetometry survey. A subsequent excavation was carried out to validate the geophysical results. The results of the geophysical survey clearly show the presence of 36 or 37 stone foundations for houses situated radially around the wall of the fort as well as of 16 or 17 similar house foundations in a central building group. The geophysical results also provided information on other buried features within the fort and also confirm the location of a third gate situated in the north-western part of the fort. The available evidence indicates that the ringfort was used for military purposes, or as a place of refuge in times of unrest, for a limited period of time during the late 5th century.
""During the summer of 2008 archaeological excavations and geophysical prospection surveys were c... more ""During the summer of 2008 archaeological excavations and geophysical prospection surveys were carried out in the mountain
tundra region of north-eastern Sweden. The investigations focused on locating settlement remains connected with a Middle
Neolithic tool production site discovered by archaeologists in 2001.
Magnetic susceptibility surveys using the MS2D system by Bartington Instruments and an EM38 by Geonics measuring the
Inphase component of the electromagnetic field were used for the prospection of measureable traces of anthropogenic activity
and structures such as hearths and middens within the estimated settlement area. Soil samples for phosphate analysis were
also collected and analysed using a field analysis method developed by Merck.
The magnetic susceptibility measurements successfully located a waste heap containing fire-cracked stones and refuse from a
seasonal settlement. The results of the survey were confirmed by subsequent archaeological excavations, which also revealed
a piece of resin with the imprint of a human tooth. One additional piece of resin dated the site to 3340 to 3100 BC. The soil
phosphate analysis showed slightly increased values over the central part of the site and over the heap of fire-cracked stones.
Comparison between the MS2D and EM38 measurements revealed a weak impact of the bedrock on the results, indicating a
potential for the applicability of magnetic surveys to this specific type of environment. Future geophysical archaeological
prospection in the Swedish mountain tundra region could benefit from a combined approach using high-resolution
magnetometry and magnetic susceptibility measurements.""
Gradiometer surveys have been carried at three Iron Age and early medieval sites on the island of... more Gradiometer surveys have been carried at three Iron Age and early medieval sites on the island of Gotland, Sweden. Previous experiences of poorly executed magnetic surveys combined with a misconception among archaeologists that the Gotlandic sedimentary bedrock would preclude the success of any magnetic investigations on the island have, until now, prevented the extended use of the method within archaeological projects. The purpose of the present study was to test this presumption while searching for in situ buried remains of high-temperature crafts, such as metal and glass working. The location of the survey grids was guided by concentrations of previously recovered high-temperature craft finds from metal detector surveys and excavations. The results indicate that the magnetometer is a valuable tool for detecting the presence of preserved high-temperature craft structures in the Gotlandic soil. An additional result indicates that in this area the magnetometer can easily identify remains of ploughed-over Iron Age stone foundation houses and stone boundary walls. This is possible because of the prehistoric population's preference of using glacially deposited, igneous rocks in such constructions. It can thus be concluded that the uniformly non-magnetic character of the Gotlandic bedrock provides excellent conditions for conducting magnetic surveys.
A ground-penetrating radar (GPR) survey and an archaeological excavation of the buried remains of... more A ground-penetrating radar (GPR) survey and an archaeological excavation of the buried remains of the Medieval Dominican convent in Sigtuna (Raä 30) produced new information on the ground plan of the convent and the condition of the buried structures remaining at the site.The site has hitherto seen surprisingly little archaeological investigations, and it is now over 30 years since the previous fieldwork. In addition to the foundation walls of the convent and adjoining structures, GPR also revealed an earlier building phase and a previously unknown lavatorium connected to the southern range. These interpretations were confirmed by excavations in September 2009. A suggestion as to the function of the various buildings, based on comparison with other convents, is offered.
While geophysical prospection for iron ores has a long history in Sweden the use of geophysical a... more While geophysical prospection for iron ores has a long history in Sweden the use of geophysical archaeological prospection has been limited compared to other countries. In this paper we discuss the likely reasons for this situation and present a brief history of geophysical prospection and in particular geophysical archaeological prospection in Sweden. The first use of different prospection methods, such as metal detection, earth resistance, magnetic, ground-penetrating radar, seismic and electro-magnetic prospection in Swedish archaeology are presented. The archaeological Iron Age sites of Uppåkra and Birka have been subject to relatively intensive prospection activity and are therefore mentioned separately. An overview of the current situation of geophysical archaeological prospection and related issues is given, and pitfalls and possibilities are discussed. The paper finishes with an outlook on possible future developments.
Projektet Nordliga vapenhus i Uppland genomfördes under hösten 2009 i syfte att med hjälpa av en ... more Projektet Nordliga vapenhus i Uppland genomfördes under hösten 2009 i syfte att med hjälpa av en georadarutrustning belägga förekomsten av nordliga vapenhus vid tre Uppländska kyrkor i Alunda, Tierp och Bälinge. Georadarresulten visar på ett tydligt nordligt vapenhus vid ...
During May 2014 four prehistoric ring-forts on the island of Öland, namely Gråborg, Vedby borg, B... more During May 2014 four prehistoric ring-forts on the island of Öland, namely Gråborg, Vedby borg, Bårby borg and Löts borg, have been surveyed using a motorized Ground-Penetrating Radar (GPR) system. The surveys were carried out as a part of the project “The big five”, and included high-resolution GPR data collection covering in total approximately 7.5 ha of land inside the forts. As a complement to the geophysical survey the remaining walls and surroundings of Gråborg and Vedby borg were surveyed with a Mobile Mapping System (MMS) named GeoTracker.
Determining whether a magnetic anomaly detected at an archaeological site has a natural or a cult... more Determining whether a magnetic anomaly detected at an archaeological site has a natural or a cultural source can be quite challenging in some regions of the world because of magnetic variability related to soil development and differing rock/parent material types. Though not consistently recognized, lightning is one major source for magnetic anomalies on archaeological sites that often has been overlooked and misinterpreted. A case study from the High Bank Works in south-central Ohio, USA shows the range of strike anomaly sizes, shapes, and intensities.
Den 19:e april 2012 utfördes en georadarmätning mellan gravtumba A och B i Riddarholmskyrkan i St... more Den 19:e april 2012 utfördes en georadarmätning mellan gravtumba A och B i Riddarholmskyrkan i Stockholm. Avsikten med undersökningen var att utröna om det fanns ett hålrum under golvet mellan de båda gravtumborna i kyrkans kor, eller om marken under golvplattan mellan gravtumborna bestod av någon typ av fyllnadsmaterial. Georadarmätningarna utfördes med ett ProEx-system från Malå Geoscience. Till utrustningen kopplades både en 800- och en 500MHz antenn. Undersökningarna utfördes i fyra separata profiler som vardera var drygt 12m långa. Profilerna drogs medvetet vidare ut över redan kända gravar för att tydliga referenser skulle finnas i det insamlade datamaterialet. Resultaten visar att tydliga reflektioner kan iakttagas då georadarantennen drogs över de redan kända gravarna i kyrkan. Det är troligt att de kraftiga reflektionerna bland annat orsakas av partiella tomrum under de gravhällar som täcker golvet i kyrkan. Reflektioner (hyperblar) från möjliga tegelmurar och kistor i några av gravarna är också synliga i data. Georadarresultaten från området mellan gravtumborna är, i jämförelse med övriga gravar, mycket annorlunda. Det indikerar att det under golvplattan mellan de båda gravtumborna inte finns något hålrum utan någon typ av fyllnadsmaterial. I fyllnadsmaterialet är det möjligt att flertalet lagergränser finns representerade, av vilka några är svagt synliga i radagramen.
Abstract This paper deals with archaeological prospection of an Iron Age farm site in Toland, Fre... more Abstract This paper deals with archaeological prospection of an Iron Age farm site in Toland, Fresta parish, Uppland County in Sweden. The purpose of the paper has been to see whether the geophysical methods applied (GPR & EM-38) could produce useful results ...
Rapporter från Arkeologiska forskningslaboratoriet 22, Mar 18, 2014
This report covers a magnetic survey in 2011 of a monument site (settlement and fields) at Lyrung... more This report covers a magnetic survey in 2011 of a monument site (settlement and fields) at Lyrungs in Stånga parish on the island of Gotland, Sweden. The survey was followed up by a control excavation of 1 m2 at one of the recorded anomalies. The finds mainly consisted of fragmented loom weights, glass tesserae
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ringforts on the island of Öland, east of the Swedish mainland. One of them, Sandby borg, was selected for further investigations by means of a ground-penetrating radar (GRP) and magnetometry survey. A subsequent excavation was carried out to validate the geophysical results. The results of the geophysical survey clearly show the presence of 36 or 37 stone foundations for houses situated radially around the wall of the fort as well as of 16 or 17 similar house foundations in a central building group. The geophysical results also provided information on other buried features within the fort and also confirm the location of a third gate situated in the north-western part of the fort. The available evidence indicates that the ringfort was used for military purposes, or as a place of refuge in times of unrest, for a limited period of time during the late 5th century.
tundra region of north-eastern Sweden. The investigations focused on locating settlement remains connected with a Middle
Neolithic tool production site discovered by archaeologists in 2001.
Magnetic susceptibility surveys using the MS2D system by Bartington Instruments and an EM38 by Geonics measuring the
Inphase component of the electromagnetic field were used for the prospection of measureable traces of anthropogenic activity
and structures such as hearths and middens within the estimated settlement area. Soil samples for phosphate analysis were
also collected and analysed using a field analysis method developed by Merck.
The magnetic susceptibility measurements successfully located a waste heap containing fire-cracked stones and refuse from a
seasonal settlement. The results of the survey were confirmed by subsequent archaeological excavations, which also revealed
a piece of resin with the imprint of a human tooth. One additional piece of resin dated the site to 3340 to 3100 BC. The soil
phosphate analysis showed slightly increased values over the central part of the site and over the heap of fire-cracked stones.
Comparison between the MS2D and EM38 measurements revealed a weak impact of the bedrock on the results, indicating a
potential for the applicability of magnetic surveys to this specific type of environment. Future geophysical archaeological
prospection in the Swedish mountain tundra region could benefit from a combined approach using high-resolution
magnetometry and magnetic susceptibility measurements.""
"
ringforts on the island of Öland, east of the Swedish mainland. One of them, Sandby borg, was selected for further investigations by means of a ground-penetrating radar (GRP) and magnetometry survey. A subsequent excavation was carried out to validate the geophysical results. The results of the geophysical survey clearly show the presence of 36 or 37 stone foundations for houses situated radially around the wall of the fort as well as of 16 or 17 similar house foundations in a central building group. The geophysical results also provided information on other buried features within the fort and also confirm the location of a third gate situated in the north-western part of the fort. The available evidence indicates that the ringfort was used for military purposes, or as a place of refuge in times of unrest, for a limited period of time during the late 5th century.
tundra region of north-eastern Sweden. The investigations focused on locating settlement remains connected with a Middle
Neolithic tool production site discovered by archaeologists in 2001.
Magnetic susceptibility surveys using the MS2D system by Bartington Instruments and an EM38 by Geonics measuring the
Inphase component of the electromagnetic field were used for the prospection of measureable traces of anthropogenic activity
and structures such as hearths and middens within the estimated settlement area. Soil samples for phosphate analysis were
also collected and analysed using a field analysis method developed by Merck.
The magnetic susceptibility measurements successfully located a waste heap containing fire-cracked stones and refuse from a
seasonal settlement. The results of the survey were confirmed by subsequent archaeological excavations, which also revealed
a piece of resin with the imprint of a human tooth. One additional piece of resin dated the site to 3340 to 3100 BC. The soil
phosphate analysis showed slightly increased values over the central part of the site and over the heap of fire-cracked stones.
Comparison between the MS2D and EM38 measurements revealed a weak impact of the bedrock on the results, indicating a
potential for the applicability of magnetic surveys to this specific type of environment. Future geophysical archaeological
prospection in the Swedish mountain tundra region could benefit from a combined approach using high-resolution
magnetometry and magnetic susceptibility measurements.""