The Portuslimen Project. Geophysical survey at Tarragona, and the constraints of modern urban areas

Over the past few months of field survey, work has swung around to a series of projects lined to Roman ports in the Mediterranean. In June and July I headed back for a season of excavations at Portus, and in … Continue reading

Over the past few months of field survey, work has swung around to a series of projects lined to Roman ports in the Mediterranean. In June and July I headed back for a season of excavations at Portus, and in August and September geophysical survey at the site of Ephesus in Turkey (more on this in a future post). In October and November work has commenced on a geophysical and topographic survey of the Roman port area of the town of Tarragona in Catalonia, Spain. The work, together with that of Ephesus, forms part of the Roman Meditteranean Ports (RoMP) project, or Portuslimen (http://portuslimen.eu/). A component of this project involves the survey of a number of port sites, to understand the form and extent of these sites, and help analyse the ways in which they may have functioned through time. The work at Tarragona is being conducted in collaboration with colleagues from l’Institut Català d’Arqueologia Clàssica (ICAC).

 

The modern port of Tarragona, with its harbour, docks and factories

The issue with Tarragona is that the development of the town and port spans from the pre-Roman period, to the establishment of the Roman town in the third century BC, to Late Roman and Visigothic settlement in the 6th, 7th and 8th centuries, and later Islamic influence. Over this time the town and its port expanded and contracted, and archaeological deposits were buried under fluvial deposits from the Francolí river to the west of the port. Later post-medieval expansion of the town, particularly in the 19th and 20th centuries saw much of the Roman and later port built over, and a new harbour constructed over the remains of the ancient port. The aim of our survey is to attempt to locate significant structural remins of the Roman port and harbour through intrusive methods. The good news is that a number of areas in the city have been excavated in the past 40 years, which helps in the location of the survey to gain as much as possible from the efforts. The bad news is that, due to the modern town plan, many of the survey areas are constrained by modern buildings and infrastructure. Thus our work has to use some specific techniques to conduct survey in the areas that are available. This includes topographic survey and location of survey grids using RTK GPS and total station survey, and use of GPR and ERT along streets and in plazas to map buried remains.

Set up of the GPS and GPR by the University of Southampton team in the Placa dels Carros

Set up of the GPS and GPR by the University of Southampton team in the Placa dels Carros

 

The GPS base station collecting static data for the survey

The GPS base station collecting static data for the survey

 

Fortunately for the University of Southampton team, the open plazas of the town provided sufficient space for static data to be collected by the GPS base station, and for a series of preliminary stations to be established using the GPS. Where the streets became narrow a total station was used to establish further stations in a traverse around the port area of the town.

Geophysical survey s far has focused on 500MHz GPR, propagating 3-4m below the modern street level to find the buried archaeology. In some of the streets in the northern part of the port area, particularly along the roads close to the Roman baths and theatre a number of walls and other features are visible. As the survey progresses southwards, however, modern infrasructure such as manhole covers, and the nature of the made-up ground close  to the modern harbour, make the results more difficult to interpret. The restrictions in terms of spatial coverage have also provided a challenge in terms of data interpretation.

Total station survey in one of the streets of Tarragona

Total station survey in one of the streets of Tarragona

 

500MHz GPR survey in one of the plazas

500MHz GPR survey in one of the plazas

 

To better understand the geoarchaeology of the site we have been applying Electrical Resistivity Tomography (ERT) to record both archaeology and deeper deposits in the town. The main constraint with this is that the paved areas of the town preclude the use of survey probes (these cannot be dug through cement and Tarmac). Thus we have had to adapt using a system of electrode copper conductors and a conductive gel. Most surfaces will allow an electrical current to be passed through them, but asphalt and Tarmac act as insulators, meaning that for the ERT to work long stretches of cement pavement need to be surveyed.

A conductor formed from crocodile clips, wire and pipe end copper usually used for plumbing.

A conductor formed from crocodile clips, wire and pipe end copper usually used for plumbing.

The ERT profile being conducted adjacent to the Roman theatre

The ERT profile being conducted adjacent to the Roman theatre

 

In spite of our initial misgivings, the conductors and gel, with the ERT equipment, have proved to work very well indeed. The profile alongside the Roman theatre has revealed a number of areas of walls and rubble aligned adjacent to the excavated theatre remains. The team hope to conduct a long profile of ERT in the southern part of the modern port which, together with the boreholes of Ferreol Salomon, will investigate the nature of the harbour deposits.

The survey work is being conducted until 15th November, and there are many features of the topography of the ancient harbour that remain to be discovered, including the line of the Roman seafront and mole.

The bay to the east of the port

The bay to the east of the port

 


Between the Desert and the Nile. Theban Harbours and Waterscapes

Back in 2011 the Theban Harbours and Waterscapes Survey (THaWS) started with a field season of geophysics. This Egypt Exploration Society project (www.ees.ac.uk), directed by Dr Angus Graham,  was established with the aim of using different techniques to study the … Continue reading

The West Bank of Thebes

The West Bank of Thebes

Back in 2011 the Theban Harbours and Waterscapes Survey (THaWS) started with a field season of geophysics. This Egypt Exploration Society project (www.ees.ac.uk), directed by Dr Angus Graham,  was established with the aim of using different techniques to study the settlements and temples on the east and west banks of the Nile, and how they relate to the changing floodplain and river. Unfortunately the season had to be aborted after the 25th January revolution, and the survey was postponed to the 2012 season, when the fieldwork progressed at a cracking pace.

After five years of the project a large quantity of survey data, together with sedimentary data from auger samples, has been collected and is pushing forward some tentative interpretations about the archaeology and geomorphology of the area. Fieldwork in areas as diverse as Malqata, Birket Habu and the floodplain in front of Kom El Hetan and the Ramesseum has provided food for thought on the depth of ancient ground levels and the organisation of the waterways on the West Bank, with interesting results from some of the East Bank work, including Karnak.

For the 2015 season the fieldwork has shifted up a notch with a larger and more diverse team. The plan was to run different geophysical survey techniques, while also continuing the auger sample strategy and processing of samples from the 2014 and 2015 seasons. Work has very much focused on Electrical Resistivity Tomography (ERT) surveys on the West Bank, particularly in the area to the east of the Ramesseum heading up to the current course of the Nile, with Ginger Emery working on the instrument. This has been complemented by an intensive season of auger work conducted by Ben Pennington and Willem Toonen, to investigate changes in the sediments represented in the ERT.

ERT survey under way on the West Bank

ERT survey under way on the West Bank

Auger work along ERT profile 32, West Bank

Auger work along ERT profile 32, West Bank

The survey has allowed a solid dataset to be collected running from c.600m to the east of the Ramesseum all the way the the modern banks of the Nile, with the resistivity and auger data integrating to allow some more nuanced interpretations of the development of the floodplain and the presence of possible man-made canals to be ascertained. The work in this area relates closely to the function of temples further to the south between the Birket Habu and the Ramesseum.

ERT profile running at the foot of the Colossi of Memnon, Kom El Hetan

ERT profile running at the foot of the Colossi of Memnon, Kom El Hetan

This week we have focused the work in the area of Kom El Hetan. Previous seasons provided information on the axis of theTemple of Amenhotep and the possible presence of channels associated with the temple. The aim this week has been to expand on this information with more intensive ERT and Ground Penetrating Radar (GPR) survey in the area.

ERT survey at Kom El Hetan

ERT survey at Kom El Hetan

Hopefully by the end of the week we will have a series of close (5m) profiles of ERT data to model, and GPR data at 0.5m intervals across the front of the Colossi, in the first court, and in the third court for comparison, with a second plan to conduct more GPR profiles in the fields to the south to detect the possible enclosure of the temple. It promises to be an exciting week.

There have been trials and tribulations in the fieldwork, including negotiations with landowners, and issues with the burning of sugar cane chaff during the first two weeks. There have also been compensations, not least in the form of tea and cake, the latter being provided by the wife of Sumara, one of our workmen.

Burning sugar cane chaff promises to engulf the ERT equipment

Burning sugar cane chaff promises to engulf the ERT equipment

Husam cuts the cake provided by Sumara's wife. One of the perks of fieldwork in Egypt!

Husam cuts the cake provided by Sumara’s wife. One of the perks of fieldwork in Egypt!

The fieldwork will be carrying on at Thebes until 1st April. However, results from the previous seasons of work are presented in the last three editions of the Journal of Egyptian Archaeology, and in other papers listed below. Happy reading!

 

Graham, A. and Strutt, K. 2012, The Theban Harbours and Waterscapes Survey. Recent Fieldwork to Investigate the Canals and Harbours on the West and East Banks at Ancient Thebes (Luxor), Egypt. The Newsletter of the International Society for Archaeological Prospection 31, April 2012, 6-7.

Graham,A., Strutt, K., Hunter, M., Jones, S., Masson, A., Millett, M., Pennington, B. 2012, Reconstructing Landscapes and Waterscapes in Thebes, Egypt. In Journal for Ancient Studies eTopoi, 3, 135-142.

Graham, A., Strutt, K.D., Hunter, M. , Jones, S., Masson, A., Millet, M., and Pennington, B.T. 2012, Theban Harbours and Waterscapes Survey, 2012. Journal of Egyptian Archaeology 98, 27-42.

Graham, A. and Strutt, K. 2013, Ancient Theban Temple and Palace Landscapes. In Egyptian Archaeology 43, Autumn 2013, 5-7.

Graham, A, Strutt, K., Emery, V.L., Jones, S. and Barker, D. 2014, Theban Harbours and Waterscapes Survey, 2013. The Journal of Egyptian Archaeology 99, 35-52.

Graham, A. and Strutt, K. (forthcoming), Ancient Theban Temple and Palace Landscapes. Egyptian Archaeology. Journal of Egyptian Archaeology 100.


Old Sarum Update

For the last few weeks a fair amount of preparation has been undertaken by various members of staff at the University of Southampton for a press release on the fieldwork conducted at Old Sarum (see previous blog post http://kdstrutt.wordpress.com/2014/04/21/in-the-castle-called-seresberi-old-sarum-and-a-new-survey-of-the-inner-and-outer-baileys/). Peter … Continue reading

For the last few weeks a fair amount of preparation has been undertaken by various members of staff at the University of Southampton for a press release on the fieldwork conducted at Old Sarum (see previous blog post http://kdstrutt.wordpress.com/2014/04/21/in-the-castle-called-seresberi-old-sarum-and-a-new-survey-of-the-inner-and-outer-baileys/). Peter Franklin and colleagues at the press office have worked hard to produce the finished story, and today things finally came together with a bit of a whirlwind of media attention. The finds of the project to date illustrate the potential of non-intrusive archaeological methodologies to elucidate on the archaeology of a particular site or landscape, without harming the material culture and with some strong underlying scientific concepts on which to base  some degree of interpretation and narrative.

Greyscale image of the magnetometry from the south of the outer bailey (top) and the interpretation plot for the data overlaid on LiDAR for the area (© LiDAR data Environment Agency copyright and/or database right 2014. All rights reserved.)

Greyscale image of the magnetometry from the south of the outer bailey (top) and the interpretation plot for the data overlaid on LiDAR for the area (© LiDAR data Environment Agency copyright and/or database right 2014. All rights reserved.)

The step from geophysical survey data to coherent archaeological narrative is a big one, and one of the reasons that our interpretations to date err on the side of caution. What is apparent from the results is the urban plan of a substantial medieval city, and an array of different forms of structure and associated features in the outer bailey at Old Sarum. Hopefully the results and their wider dissemination at this stage will help to generate interest in the site, the methodology used, and the wider applications of these approaches to archaeological research.

To date the results have been reported in a number of sources. Online the sources include:

BBC News   http://www.bbc.co.uk/news/uk-england-wiltshire-30300837

The Independent   http://www.independent.co.uk/news/science/archaeology/archaeologists-find-vast-medieval-palace-buried-under-prehistoric-fortress-at-old-sarum-9898759.html

The Telegraph   http://www.telegraph.co.uk/earth/environment/archaeology/11269753/Medieval-city-uncovered-by-archaeologists-and-not-a-spade-in-sight.html

More will hopefully follow tomorrow. Above all else the results show the pertinence of student involvement in research-led teaching, from developing an understanding of the archaeological and scientific theory for the work, to dealing with practical aspects of survey and undertaking fieldwork, to being involved in the processing and interpretation of data. The results at Old Sarum are testament to the peerless hard work and dedication of the students on the project, as well as the staff involved in their supervision.

Notes:

For images or for interviews with Kris Strutt, please contact Peter Franklin, Media Relations, University of Southampton. Tel: 023 8059 5457 email: franklin@southampton.ac.uk

For more information about the Archaeological Prospection Service of Southampton (APSS) visit:http://www.southampton.ac.uk/archaeology/research/groups/archaeological_prospection_service_southampton.page

 

For more about the Old Sarum and Stratford-Sub-Castle Archaeological Survey Project visit: http://www.southampton.ac.uk/archaeology/research/projects/old_sarum_and_stratford_sub_castle.page

 

For more information about Archaeology at Southampton visit: http://www.southampton.ac.uk/archaeology/index.page

For more information about English Heritage visit: http://www.english-heritage.org.uk/

Through world-leading research and enterprise activities, the University of Southampton connects with businesses to create real-world solutions to global issues. Through its educational offering, it works with partners around the world to offer relevant, flexible education, which trains students for jobs not even thought of. This connectivity is what sets Southampton apart from the rest; we make connections and change the world. http://www.southampton.ac.uk/

http://www.southampton.ac.uk/weareconnected

 


New Discoveries at Ostia Antica and the Isola Sacra

  The new discovery of extensive urban remains to the north of the river Tiber at Ostia Antica http://www.portusproject.org/blog/2014/04/new-city-wall-discovered-ostia/#.U063XyX5rTc.twitter highlights part of the survey project conducted between 2008 and 2012 across the Isola Sacra, the area of delta between Ostia … Continue reading

 

David Knight undertaking magnetometry in the vicinity of the Tiber levee on the Isola Sacra in 2008

David Knight undertaking magnetometry in the vicinity of the Tiber levee on the Isola Sacra in 2008

The new discovery of extensive urban remains to the north of the river Tiber at Ostia Antica http://www.portusproject.org/blog/2014/04/new-city-wall-discovered-ostia/#.U063XyX5rTc.twitter highlights part of the survey project conducted between 2008 and 2012 across the Isola Sacra, the area of delta between Ostia Antica and Portus. The Isola Sacra, defined by the modern line of the River Tiber to the south and east, the Fossa Traiana to the north, and the Tyrrhenian Sea to the west, covers some 250 hectares, although the prograding nature of the Tiber Delta means that the ancient Roman coastline lies some 1.5km inland from its modern counterpart, reducing the area to 150 hectares.

The Isola has been a relatively unknown area relative to the sites of Portus and Ostia Antica. Although excavation of the Necropolis di Porto in the 1940s revealed the line of the Via Flavia connecting Ostia Antica with Portus, and tombs dating from the 2nd, 3rd and 4th centuries, the ‘sacred island’ has been the focus of scant investigation, beyond archaeological findspots and more recent investigation for mitigation works (see gazetteer in Germoni et al. 2011). Survey work between 2008 and 2012 focused on the production of a high resolution magnetometer survey of the landscape, covering most of the area between the ancient coastline, close to the line of the Via della Scafa, and the Tiber and Fossa Traiana. This survey was not a hunt for possible extensions of urban areas across the Tiber or  the Fossa, but an attempt to understand the formation of this part of the delta in terms of geoarchaeological material, and the settlement and use of the zone, particularly for the Republican and Imperial periods, and the development of both Ostia Antica and Portus.

 

Results of the magnetometer survey in the southern part of the Isola Sacra. Satellite image courtesy of DigitalGlobe

Results of the magnetometer survey in the southern part of the Isola Sacra. Satellite image courtesy of DigitalGlobe

Seven seasons of survey work were conducted over the area, representing a massive effort by staff and students at the University of Southampton, the University of Cambridge and the British School at Rome, directed by Prof. Simon Keay and Prof. Martin Millett. Gridding and topographic survey was conducted with total station and RTK GPS, allowing the entire landscape to be gridded prior to the geophysical survey being conducted. Bartington Instrument fluxgate gradiometers were then used to survey across the landscape, covering an area of 150 hectares, to add to the 260 hectares covered at Portus in previous seasons, picking up on faint variations in the Earth’s magnetic field caused by buried archaeological deposits.

RTK GPS being used to survey in the vicinity of Ostia Antica by the University of Southampton and BSR team

RTK GPS being used to survey in the vicinity of Ostia Antica by the University of Southampton and BSR team

The survey deepened our understanding of the complexity of archaeological deposits across the Isola, indicating the presence of significant waterways and canals associated with Portus and the Isola Sacra, together with a system of smaller canals for drainage and irrigation, or pre-Roman or Roman date. Compared with other data such as satellite imagery, a full assessment of the nature of archaeological features was conducted (Keay, Millett and Strutt 2014). In addition targeted use of geophysical survey methods has elucidated on the presence of archaeological remains, including the presence of Late Antique walls and structures close to the Episcopio near Portus, found during GPR survey in the area.

Image showing magnetometry results superimposed on Aereo Militare image from 1957, showing the presence of the canal traversing the Isola Sacra

Image showing magnetometry results superimposed on Aereo Militare image from 1957, showing the presence of the canal traversing the Isola Sacra (from Keay, Millett and Strutt 2014)

 

 

MSc students from the University of Southampton carrying out a GPR survey in the vicinity of the Episcopio, between Portus and the Isola Sacra

MSc students from the University of Southampton carrying out a GPR survey in the vicinity of the Episcopio, between Portus and the Isola Sacra

The results of the geophysics shows traces of the formation of the delta in the area of the Isola, including magnetic features associated with the prograding nature of the delta, and previous flow of the Tiber. This is particularly marked on the Isoal close to the Fiume Morto or ancient bend in the Tiber close to Ostia Antica. The significant canal that runs from Portus appears to run all of the way across the Isola, arriving close to the modern east – west course of the Tiber.

The canal visible in the south of the Isola Sacra (from Keay, Millett and Strutt 2014)

The canal visible in the south of the Isola Sacra (from Keay, Millett and Strutt 2014)

It is in this area that the substantial remains of an extension to the town of Ostia was found. The results indicate the presence of warehouses and large municipal buildings, some measuring 140m by 80m in length and breadth. The structures are enclosed by the line of a large defensive wall, with rectangular towers, each measuring 8m across.

Detail from the magnetometer survey results from the southern part of the Isola Sacra

Detail from the magnetometer survey results from the southern part of the Isola Sacra

The findings of the urban area are exciting in their own right. However what is more edifying is the relationship between this area and the surrounding hinterland of this complex port system. Beyond the gates of the city lies a landscape of fluvial and canal features linking the wetland of the delta, with its salt pans, fields and marble marshalling areas, with the River Tiber and the surrounding settlements and farms of the Tiber Delta. The results of the survey present an image of a complex and nuanced port and fluvial system, requiring considerable further analysis to understand the full significance of the delta area in relation to its principal urban areas and the surrounding landscape.

 

Press Sources

http://www.independent.co.uk/news/science/archaeology/size-matters-crucial-ancient-roman-city-ostia-was-40-bigger-than-previously-thought-after-british-team-uncovers-new-ruins-9265461.html

 

http://www.telegraph.co.uk/earth/environment/archaeology/10770480/Ancient-Rome-was-bigger-than-previously-thought-archaeologists-find.html

http://www.lastampa.it/2014/04/16/italia/cronache/scoperta-unostia-antica-segreta-era-pi-grande-dellantica-pompei-f0SBt3SkweayIHMqGjmHeO/pagina.html

 

http://www.leggo.it/NEWS/ROMA/ostia_antica_segreta_pi_amp_ugrave_grande_pompei_foto/notizie/636381.shtml

 

http://roma.repubblica.it/cronaca/2014/04/16/news/ostia_antica_segreta_pi_grande_pompei-83783253/?ref=HREC1-7

 

http://video.repubblica.it/edizione/roma/scoperta-ostia-antica-segreta-era-il-doppio-di-pompei/163069/161559?ref=nrct-12

References

Germoni, P., Millett, M., Keay, S. And Strutt, K. 2011, The Isola Sacra: reconstructing the Roman landscape. In Proceedings of the Portus Workshop, March 3rd 2008, Rome.

Keay, S., Millett, M. and Strutt, K. 2014, The Canal System and Tiber Delta at Portus. Assessing the Nature of Man-Made Waterways and their Relationship with the Natural Environment . In Journal of Water History, 6, 1, 11-30.

 


Archaeological Survey at Ras Al Hadd, Oman

Over the last few weeks a team from the University of Southampton has been working with a team from the British Museum, surveying the archaeological site at Ras Al Hadd. The focus of the survey work was to carry out … Continue reading

Over the last few weeks a team from the University of Southampton has been working with a team from the British Museum, surveying the archaeological site at Ras Al Hadd. The focus of the survey work was to carry out a topographic survey of the site, and to conduct magnetometer and GPR survey of areas of the occupation mound, prior to the commencement of excavation of the site. In addition the geophysical survey grid was used as the basis for intensive surface collection across the western portion of the site.

The fort at Ras Al Hadd

The fort at Ras Al Hadd

The Bronze Age and Iron Age archaeology at the site forms a mound on  the coastal plain a few kilometres from the tip of the south-east limits of the Arabian Peninsula. Later settlement has covered most of the site, including a substantial fort and new mosque. The remnants of post-medieval defence overlie the mounds of the later prehistoric settlement, one of a number in the area of the coast. It is the later archaeology that is immediately striking upon visiting Ras Al Hadd. A number of old cannon litter the village, some propped on breeze block plinths, some lying forgotten. Others are located in the fort, and lines of Martini-Henry rifles line the walls of the entrance to the courtyard. In the vicinity of the inlet and lagoon to the west of the site, a solitary tower guards the entrance to the inlet and  the reaches of the lagoon.

The lagoon to the west of Ras Al Hadd

The lagoon to the west of Ras Al Hadd

The focus of the survey was, however, the prehistoric material at Hadd. The survey utilised a number of techniques to map the area. The survey grid was established using RTK GPS, with the instrument also being used to map the topography across the site and the surrounding coastal plain between the mound and lagoon. Surface features were also surveyed in for comparison with the geophysical survey results.

GPS survey under way

GPS survey under way

Phil Riris carrying our magnetometer survey

Phil Riris carrying our magnetometer survey

The site was also surveyed using magnetometry and GPR, focusing on the western and northern parts of the mound,where modern occupation has affected the archaeology the least, and within the interior of the fort. Results of the survey revealed a number of potential archaeological features, including remains of earlier phases of the fort, Iron Age pits, and cairns. In addition to the geophysics, the British Museum team and a team of workmen undertook a systematic surface collection of a part of the surveyed area. The preliminary results show the strength of the methodology incorporating such techniques, with the plot of the fieldwalking overlying on the geophysics, and giving some clear pointers as to the nature of the ancient deposits.

Fieldwalking being carried out along the western side of the mound

Fieldwalking being carried out along the western side of the mound

One of the outcomes of travelling in the area was the opportunity to take a cursory look at the coastal area with a radius of a few kilometres from Hadd. The terrain shows the same plain, covered with thorn scrub and coastal inlets, but with a number of small occupation mounds breaking the topography. Indicating quite a dispersed settlement and use of different sites by the population, from prehistory up until more recent times. An amazing landscapewith hopefully much further scope for work.


Guest Blog: Will Heard – Spring 2013 Survey Results Part 2

Last week we published a guest post from Will Heard, as a summary of the Spring Survey that the University of Southampton students carried out this April-May. Here is Will’s second and final blog post about the survey results. Thanks again to Will! — Basing House Spring Survey Part 2 by Will Heard, 2013 Will […]

Last week we published a guest post from Will Heard, as a summary of the Spring Survey that the University of Southampton students carried out this April-May. Here is Will’s second and final blog post about the survey results.

Will Heard

Will Heard

Thanks again to Will!

Basing House Spring Survey Part 2

by Will Heard, 2013
Will is a third year undergraduate student, with interests in survey, geophysics and the use of computers for archaeological purposes. He is interested in any period of history, having worked at Basing House and on a Bronze Age site amongst others.  He is currently working on his undergraduate dissertation, which aims to use GIS systems to reveal the theoretical effectiveness against invasion of a small section of the World War II G.H.Q Line in Essex.

The Motte Resistivity Survey

Figure 2 shows the resistivity plot of part of the Motte interior with notable features enclosed in coloured lines. The bottom left high resistivity feature is most probably related to the still accessible cellar, which can be seen as a large depression on the contours.

The  high resistivity feature at the far bottom of the image has no associated topographic evidence, but it is situated in a position that may suggest it is a continuation of the feature running parallel to the cellar. If this is so, then the high resistivity feature next to the cellar may not be directly related to  it after all. The other most interesting feature is the slight low resistance feature highlighted in green, which represents a dip on the topographic model. The ground raises up to a point which is a well (circled white in Figure 3). The presence of the well leads to the assumption that this area was some sort of courtyard or open air space. This is supported by Peer’s plan of his excavations (Figure 1).

Figure 1 - Plan of the Old House as excavated by Peers. After (Royal Archaeological Institute 1924: 362).

Figure 1 – Plan of the Old House as excavated by Peers. After (Royal Archaeological Institute 1924: 362).

Figure 2 - Resistivity Survey of part of the motte interior. Notable features are enclosed by coloured lines. Negative ohm values caused by the high pass filter. Contours from a raster. ArcGIS 10.1.

Figure 2 – Resistivity Survey of part of the motte interior. Notable features are enclosed by coloured lines. Negative ohm values caused by the high pass filter. Contours from a raster. ArcGIS 10.1.

Figure 3  - Motte interior resistivity draped over the 3D TIN surface. From the north. Light from the east at 45 degrees. Vertical exaggeration at 1.5.

Figure 3 – Motte interior resistivity draped over the 3D TIN surface. From the north. Light from the east at 45 degrees. Vertical exaggeration at 1.5.

The New House Resistivity Survey

The New House site was the largest of the three areas surveyed with Resistivity and has a lot of strong features. The most obvious features are the straight lines along the entire left side of Figure 13. These are undoubtedly buried foundations of the raised New House.

The circular anomalies are towers of the sort seen in Hollar’s drawing (see Figure 15). The strength of these anomalies suggests excellent preservation and indeed, an excavation uncovered some of these remains and did not fully fill in the trenches. The resulting depression in the topography can be seen in the foreground of Figure 14.

The very low (white) anomalies in the same area are possibly caused by a slow build-up of moist, humic soils in the unfilled excavation trenches. Given the aforementioned evidence, it appears unlikely the anomalies are of historical origin. However, further south in Figure 13, some of the unexcavated strong circular anomalies enclose areas of extremely low resistance. These may be the result of filled sunken floors, or quarrying straight after the final Civil War siege.

Another area of interest is on the right of Figure 13, which is circled by a green line. This area is highly variable, with pixels of very high and low resistance and it is unclear what these readings represent. More areas of interest include the horizontal line feature and various other patches of high resistance in Figure 13.

Figure 4 - Resistivity Survey of the New House area. Notable features are enclosed by coloured lines. Negative ohm values caused by the high pass filter. Contours from a raster. ArcGIS 10.1.

Figure 4 – Resistivity Survey of the New House area. Notable features are enclosed by coloured lines. Negative ohm values caused by the high pass filter. Contours from a raster. ArcGIS 10.1.

Figure 5 - New House resistivity plot draped over the 3D TIN. Red lines show features with associated topographic variations. From the north. Light from the east at 45 degrees. Vertical exaggeration at 1.5. ArcGIS 10.1.

Figure 5 – New House resistivity plot draped over the 3D TIN. Red lines show features with associated topographic variations. From the north. Light from the east at 45 degrees. Vertical exaggeration at 1.5. ArcGIS 10.1.

Figure 6 - Wenceslaus Hollar's 'The Siege of Basing House'. The text reads 'A THE OLD HOUSE. B. THE NEW. C. THE TOWER THAT IS HALFE BATTERED DOWN. D. KINGS BREASTWORKS. E. PARLAMENTS BREASTWORKS' [sic]. After (Wikipedia 2013)

Figure 6 – Wenceslaus Hollar’s ‘The Siege of Basing House’. The text reads ‘A THE OLD HOUSE. B. THE NEW. C. THE TOWER THAT IS HALFE BATTERED DOWN. D. KINGS BREASTWORKS. E. PARLAMENTS BREASTWORKS’ [sic]. After (Wikipedia 2013)

Everyone was very pleased with how the survey went, despite some bitterly cold days and an afternoon of menacing weather in the first week. I hope that these highlights from the data illustrate just what can be done with all the data we gathered although someone more savvy with the computer software could do things much more impressive than this. Various sub-surface features were linked to surface features observable on the topographic model.  Some of these were easily dated thanks to their close proximity to known quantities, like the New House, while others were less easily identifiable. The lack of confident dates on numerous features is a reason for more work, especially excavation, on site in the future. Lastly, I would personally encourage anybody who has not been before, to go and see this great site.

References

(1924). Proceedings at Meetings of the Royal Archaeological Institute. The Archaeological Journal 81. Royal Archaeological Institute. 315-380. (Basing House pp. 359-364).

English Heritage (last updated 2004). National Monuments Record, Basing House. at: http://archaeologydataservice.ac.uk/archsearch/record.jsf?titleId=1033242; 27 Feb. 2013.

English Heritage. (2007a). Pastscape, Basing House at: http://www.pastscape.org.uk/hob.aspx?hob_id=240444; 01 May 2013.

Wikipedia. (2013). Wenesclaus Hollar – The Siege of Basing House at: http://en.wikipedia.org/wiki/File:Wenceslaus_Hollar_-_The_Siege_of_Basing_House.jpg; 6 Mar 2013.

Wikipedia. (2013). Launceston Castle at: http://en.wikipedia.org/wiki/File:Launceston_Castle_-_geograph.org.uk_-_22242.jpg; 12 Jul 13


Filed under: Spring Survey, Student Research Post, Will Heard Tagged: building survey, gpr, gps, ground penetrating radar, leica, magnetic susceptibility, magnetometry, new house, old house, resistance survey, resistivity, survey, surveying, topographic, total station, undergraduate

Guest Blog: Will Heard – Spring 2013 Survey Results Part 1

As part of the Spring Survey that the University of Southampton students carried out this April-May, undergraduate Archaeology students who attended the fieldwork were asked to write a report summarising the survey data. One of the students that attended the Spring Survey, Will Heard, has written a summary of his report, and has kindly allowed […]

As part of the Spring Survey that the University of Southampton students carried out this April-May, undergraduate Archaeology students who attended the fieldwork were asked to write a report summarising the survey data.

One of the students that attended the Spring Survey, Will Heard, has written a summary of his report, and has kindly allowed us to share it with our readers. Will has written so much, that we’re sharing part 1 this week, and part 2 next week!

Thanks Will!

Basing House Spring Survey Part 1

Will Heard

Will Heard

by Will Heard, 2013
Will is a third year undergraduate student, with interests in survey, geophysics and the use of computers for archaeological purposes. He is interested in any period of history, having worked at Basing House and on a Bronze Age site amongst others.  He is currently working on his undergraduate dissertation, which aims to use GIS systems to reveal the theoretical effectiveness against invasion of a small section of the World War II G.H.Q Line in Essex.

Survey Summary

During March and April 2013 a topographic and geophysical survey was undertaken at Basing House by University of Southampton staff and students. Most of the topographic survey was carried out in week one between the 18th and 22nd March, while all of the geophysical survey was carried out in week two, between the 8th and 12th April. The work aimed to further the understanding of the sites layout and history by providing a computer model which will allow more detailed analysis of the landscape, and possibly help us see things our naked eyes cannot. The model will consolidate much of the smaller scale on site investigation (excavations, geophysics) which have been carried out and documented in the past. Similarly, future work of all types will be able to use the model to add onto a coherent body of knowledge. The geophysical and building survey, which was carried out alongside the topographic work, will add to this body of knowledge on Basing House.

Introducing the Site

The area has a long history with the earliest known finds dating from the Mesolithic era, although this occupation is not currently seen as continuing, since Neolithic remains are rare to nonexistent on the site (English Heritage 2004). Bronze Age flint, as well as Iron Age and Roman ceramics have also been recovered (English Heritage 2004). The most discussed period of the sites history starts in the Medieval period, with the construction of the Motte and Bailey castle (see central round and plateau like feature in figure 1) and later the Old and New Houses (inside and to the east of the motte in figure 1). The Motte and Bailey were erected sometime in the twelfth century AD and the Old and New Houses erected one after the other in the sixteenth century AD. The New House merited its own earthworks to the east of the Motte and Bailey and later, semi-circular Civil War gun platforms were added onto the earlier Medieval outer bank to the south. After the Civil War the houses were demolished, with much of the stonework taken and used in the nearby village. Other features include a dry and filled in part of the eighteenth century Basingstoke Canal (north edge of figure 1).

Figure 1 - OS Map data with a polygon overlaid (red line). The polygon represents the extent of the area surveyed topographically. ArcGIS 10.1. © Crown Copyright/database right 2013. An Ordnance Survey/EDINA supplied service.

Figure 1 – OS Map data with a polygon overlaid (red line). The polygon represents the extent of the area surveyed topographically. ArcGIS 10.1.
© Crown Copyright/database right 2013. An Ordnance Survey/EDINA supplied service.

Below, figure 2 shows the areas that were surveyed with resistivity equipment. The contours in this figure are derived from a raster.

Figure 2 - The area surveyed with resistivity equipment (contours derived from a raster). ArcGIS 10.1. © Crown Copyright/database right 2013. An Ordnance Survey/EDINA supplied service.

Figure 2 – The area surveyed with resistivity equipment (contours derived from a raster). ArcGIS 10.1.
© Crown Copyright/database right 2013. An Ordnance Survey/EDINA supplied service.

Since the survey produced one continuous area of data (see figure 3 and figure 4 below), the following pictures have some degree of overlap. The area has been split into four areas: A, B, C and D. The topographic areas B and C are the highlights included in this week’s blog post. In terms of the resistivity survey, the highlights were the Motte interior survey and the New House site survey.

Figure 3 - Basing House complete TIN with features overlain. ArcGIS 10.1

Figure 3 – Basing House complete TIN with features overlain. ArcGIS 10.1

Figure 4 - Basing House complete Raster with features overlain. ArcGIS 10.1

Figure 4 – Basing House complete Raster with features overlain. ArcGIS 10.1

Area B

Area B is the southernmost area surveyed and has the highest general elevation of any of this report’s areas. It comprises what is thought to be a long semi-circular bank that was possibly constructed at a similar time to the Motte and Bailey, as well as three Civil War raised gun platforms (English Heritage 2007a). These are clearly visible on the ground and are highlighted in figure 5. It is possible that the fact the three gun platforms are attached to the bank means that the bank was constructed earlier, since a connecting bank between Civil War gun platforms would not always be necessary. In the Civil War, the bank would have provided good cover against bombardment or assault from the south and so adding gun platforms to an already good fortification was the logical course of action. At points the ditch protecting the bank is deeper, for example at the westernmost end. Towards the southern end the ditch becomes very shallow. This variation is probably due to the natural topography, which gets higher as one goes further south on our model, this variation is highlighted in figure 6 below.

Figure 5 -  Area B TIN and Raster. ArcGIS 10.1.

Figure 5 – Area B TIN and Raster. ArcGIS 10.1.

Figure 6 - Area B 3D TIN with features added. From the east. Light from the east at 45 degrees. Vertical exaggeration at 1.5. ArcGIS 10.1.

Figure 6 – Area B 3D TIN with features added. From the east. Light from the east at 45 degrees. Vertical exaggeration at 1.5. ArcGIS 10.1.

Area C

Area C is the centre of the topographic survey area and comprises the Motte, Bailey and their respective ditches. The elevation of this area is generally quite high, while being lower than Area B (see figures 7 and 8 below).

Figure 7 - Area C TIN and Raster. ArcGIS 10.1.

Figure 7 – Area C TIN and Raster. ArcGIS 10.1.

Figure 8 - Area C 3D TIN with features added. From the west. Light coming from the east at 45 degrees. Vertical exaggeration at 1.5.

Figure 8 – Area C 3D TIN with features added. From the west. Light coming from the east at 45 degrees. Vertical exaggeration at 1.5.

The Motte and Bailey ditches are very deep, survive very well and show very nicely on the topographic models. All of the surviving cellars inside the motte lend support to Peer’s plan (figure 9 below).

Figure 9 - Plan of the Old House as excavated by Peers. After (Royal Archaeological Institute 1924: 362).

Figure 9 – Plan of the Old House as excavated by Peers.
After (Royal Archaeological Institute 1924: 362).

The variations on the east side of the bailey are caused by a previous excavation that was carried out before a bridge over the ditch was constructed. The yellow line (north side of figure 8 above) represents a raised piece of ground and is the location of a large tree.

The topographic model shows the Motte being higher than the Bailey. This is to be expected, both because the land naturally goes down northwards, but also because the Motte was where the Lord would have resided.

The form of the Motte and Bailey is very similar to other examples like Launceston Castle (figure 10 below).

Figure 10 - Launceston Castle. In size, it is smaller than Basing House. However, its Motte and Bailey design is similar. After (Wikipedia 2013)

Figure 10 – Launceston Castle. In size, it is smaller than Basing House. However, its Motte and Bailey design is similar.
After (Wikipedia 2013)

References

Anon. (1924). Proceedings at Meetings of the Royal Archaeological Institute. The Archaeological Journal 81. Royal Archaeological Institute. 315-380. (Basing House pp. 359-364).

English Heritage (last updated 2004). National Monuments Record, Basing House. at: http://archaeologydataservice.ac.uk/archsearch/record.jsf?titleId=1033242; 27 Feb. 2013.

English Heritage. (2007a). Pastscape, Basing House at: http://www.pastscape.org.uk/hob.aspx?hob_id=240444; 01 May 2013.

Wikipedia. (2013). Wenesclaus Hollar – The Siege of Basing House at: http://en.wikipedia.org/wiki/File:Wenceslaus_Hollar_-_The_Siege_of_Basing_House.jpg; 6 Mar 2013.

Wikipedia. (2013). Launceston Castle at: http://en.wikipedia.org/wiki/File:Launceston_Castle_-_geograph.org.uk_-_22242.jpg; 12 Jul 13

Next Week: Part 2

In the next post, we’ll look at the results from the Motte resistivity survey and the New House resistivity survey.


Filed under: Spring Survey, Student Research Post, Will Heard Tagged: building survey, gpr, gps, ground penetrating radar, magnetic susceptibility, magnetometry, new house, old house, resistance survey, resistivity, survey, topographic, total station, undergraduate, will-heard

The first major Lower Palaeolithic/Earlier Stone Age site in Greece

Two members of CAHO Dr John (Mac) McNabb and Dr James Cole (Centre for the Archaeology of Human Origins at Southampton) have been working with Greek colleagues from the University of Crete (Professor Nena Galanidou) and the University of Patras (Dr Giorgos Iliopoulos) in Western Greece, on the beautiful island of Lesvos off the coast of Turkey. Centred around the village of Lisvori, overlooking the spectacular Kalloni Gulf, the team of international collaborators are investigating the first major Lower Palaeolithic/Earlier Stone Age site in Greece. The site was first identified by two medical doctors with an interest in local archaeology who were fieldwalking the area. Professor Galanidou was called in and immediately recognised the potential significance of the site.

Further details on this exciting site have just been published in Antiquity  with additional information at the University of Crete website. Mac and James did a short geophysics (GPR) season in May this year and are returning with the full team in July to continue excavation, field walking, and geological investigation.

The landscape in which the Rodafnidia locality where the handaxes were found as seen from a nearby hill.

Dr James Cole (left), Mac (in the middle hiding behind Giorgos), and Dr Giorgos Iliopoulos (right)

 

Spring Survey – Week 2 Review

The undergraduates have finished working at Basing House for this Spring, and we’ll be back on site in a few weeks to collect  more data for some of our postgraduate students who are using the site for various projects. This is the team from Week 2. I can’t believe how much ground these guys covered! […]

The undergraduates have finished working at Basing House for this Spring, and we’ll be back on site in a few weeks to collect  more data for some of our postgraduate students who are using the site for various projects.

This is the team from Week 2. I can’t believe how much ground these guys covered! Thanks all!

Spring Survey – Week 2 Team

I thought it might be useful to give you a rundown on the different tools that we were using to record the site during the topographic, building and geophysical survey, as we keep saying things like ‘mag’ and ‘GPR’ without explaining what any of them are!

In our next post, we’ll begin to share the results of the surveys, so do check back regularly, or subscribe to the blog for updates, using the link on the navigation to the right.

Geophysical Survey

There are a few pieces of kit that we use for a geophysical survey.

Magnetometry

Magnetometry

Magnetic survey uses a magnetometer to identify the presence of magnetised iron oxides in the soil. Magnetometers are great for identifying ferrous oxides or burnt/ heated material that show up as ‘positive’ features, as well being great for finding negative features, like a pit or a ditch.  Magnetometers are great for identifying industrial areas, and buildings.

The magnetometer you see in these photos is a Fluxgate Gradiometer, which is the most commonly used type in the UK. With this instrument, we take two readings at a time.  The vertical poles on either end of the horizontal handle are the sensor-sets. Within each of the poles there are two sensors, one at the top and one at the bottom. The reading that we are measuring is the difference between the top sensor and the bottom sensor. The fluxgate sensors are always a set distance apart, normally half a metre or a metre (in this instrument, they are a metre apart).

The sensors are very sensitive and so when you are using one, you must be careful not to be wearing anything metal. As you can see from the photograph below, this often makes attire a bit unusual. Tracksuit trousers are the best option, and cheap wellies work well for footwear. Belts are an absolute no-no, and raincoats with lots of zips and poppers must be avoided. The higher up your body the metal is, the less likely it is to affect the instrument. So piercings and glasses with metal frames are sometimes okay, but ideally, should be removed.

The person operating the instrument will walk up and down in a grid of between 10-30 metres. Each grid is marked out on the ground, normally using bamboo canes placed at intervals (every two metres is a good way to do it), and the person carrying the instrument can use these canes as markers to aim for to ensure their line is aligned correctly within the grid.  You can collect the data by walking parallel lines, or in a zigzag shape.

Magnetometry – note the poncho – a coat with no metal in it is hard to find!

Magnetic Susceptibility

Magnetic Susceptibility

Magnetic susceptibility is possible because material can become temporarily magnetised: Any human activity will affect soil magnetic susceptibility. Ideally what we’re searching for is topsoil that has been affected by features buried underneath it.  Magnetic Susceptibility can be collected in continuous or single measurements. The instrument sends out a magnetic pulse, and measures the ability of the soil to hold a magnetic charge.  Human activity affects the chemical makeup of the soil, so magnetic susceptibility will be affected by this, and can be used to pick up on things like areas of a settlement where there has been lots of rubbish deposited or farming activity taking place.

To the right of this photograph, Crystal is holding the GPS; more about that piece of kit later in this post…

Resistance Survey

Resistance survey

Resistance survey works by feeding an electric current into the soil.  Sub-surface materials all have varying resistivities to an electrical current. With this technique, we measure these values, and in so doing can build up a picture of what is under the surface. Generally walls and other positive features such as trackways, cists, rubble and man-made surfaces result in high resistance, and negative features such as ditches, drains, graves, and pits result in low resistance. This is because negative features tend to have higher moisture content.

Depending upon the material and the water content, features can show up as either positive or negative. Typically stone features are high resistance, whereas ditches, depending upon their fill are negative (or low) resistance. The resistance of materials under the ground uses the ability of soil to let electric current pass through it, and this is related to the interstitial water (i.e. water in the gaps in-between) and salts within the soil.

On the last day of the survey, we had to abandon the resistance survey because there was the chance of the results being ruined by the heavy rain, and standing water.

Ground Penetrating Radar (GPR)

Ground Penetrating Radar

Ground Penetrating Radar works by firing radar pulses into the ground and recording the speed at which the signals are reflected back to the device.  These varying reflections allow a picture to be built up of the sub surface topography. GPR data are recorded in traverses, but are then joined together and sliced to produce flat layers, each layer representing measurements at a particular depth. These layers are known as time slices and can be ‘stacked up’ to provide a 3D model of the subsurface topography.  GPR is particularly good at detecting brick or stone foundations and is especially useful as it provides relative depth measurements.

Building Survey

Total Station with red laser

Total Station

In the photograph above, Dan is using a using a Total Station to carry out a building survey of the Old House.  There are two ways to use a Total Station to survey standing remains.

The total station is an electronic theodolite, which has an electronic distance meter which measure the distance and angles from the total station to a particular point. A laser is used to make this measurement. The total station sends out a beam which can either meet the surface that is being recorded, showing up as a red light (as is in the photographs above and below) or can meet with a target in the form of a prism, mounted on a staff of a fixed height.

In the first method, the building remains themselves are the target, and point by point the shape of the walls and features are recorded by the total station operator. For the Old House, the teams began with the top and bottom edges of the brickwork, and then surveyed in additional features, such as the bread ovens, doors and window frames.

Total Station with TheoLT – seeing the data live

Topographic Survey

Total Station with prism

The alternative method, involves using the machine on the tripod as a base station.  This is for the recording of changes in landscape. The total station remains in the same place, and a prism (see the photograph below) is used as a target.  The prism is moved around the site, and at each point where there is a significant change in topography (or at regular intervals, of around 5 metres) the total station operator matches the laser from the total station to the target prism and records the point.

Survey Prisms

When carrying out a survey on a site the size of Basing House, its good practice to set up base stations across the site.  We initially had fourteen base stations, which we added at the beginning of the survey. But the students had to add more, in order to record more problematic areas of the site. For instance, the ditch around the motte and bailey was hard to record without adding lots of stations all of the way round, in order for each base station to ‘see’ back to the previous station, and on to the next one.

Below, Dom is using the GPS to log a base station before we began the survey on site. Chris and Tim are adding wooden pegs in the spot that the GPS is recording; this becomes the base station.

Setting out the base stations with a total station

Global Positioning System (GPS)

A GPS uses the NAVSTAR GPS, which is a system which uses a collection of 24 satellites, controlled by the US Department of Defence, which are orbiting the earth. The GPS communicates via a signal with the satellites using a radio receiver, to work out its geographical position – this is possible because the GPS can compute the distance from the satellite by multiplying the velocity with the time the signals take to transmit from the satellite. The more satellites in range of the GPS, the better. The GPS needs a minimum of three satellites to be able to tell where it is on a horizontal plane, and at least four satellites to calculate where it is 3-dimensionally; i.e. the latitude, the longitude and the height.

Global Positioning System (GPS)

At Basing House, we used the GPS as described above; as a positioning tool, to tell us where something was; we used it both for the magnetic susceptibility data, and also for adding the base stations. But GPS can also be used as a surveying tool. In the photograph above, Lizzie is using the GPS to survey in the gatehouse of the Old House. The GPS can record the location of a series of points, so we used it to fill in gaps of the topographic survey, and the building survey. In the photograph below, you can see some of the points that we recorded up on the Bailey. I walked up and down in a grid, and took points at regular intervals, to build up a record of the topography of the Bailey.

GPS screen

Finding out more about Geophysics

I used Gaffney, C., Gater, J. (2006). Revealing the Buried Past: Geophysics for Archaeologists, The History Press: Stroud to write this blog post (my geophysics is a bit rusty and I wanted to make sure the iformation was up to date!). I really do recommend this book if you want to find out more about Geophysics prospection for archaeology.

The Archaeological Prospection Service at Southampton (APSS) website – http://www.southampton.ac.uk/archaeology/apss/ -  is also a great place to read about geophysics. Kris Strutt writes an excellent blog – http://kdstrutt.wordpress.com/ - which covers some of the work that he does with the APSS, so follow his posts to keep up to date with the projects that the team is involved in.


Filed under: Spring Survey, Survey Equipment Tagged: equipment, geophysics, global positioning system, gpr, gps, ground penetrating radar, leica, magnetic susceptibility, magnetometry, prism, resistivity, satellites, theolt, topographic, total station

Basing House Survey Final Day – A rain check and some reflections

Reblogged from Kristian Strutt: The second week of survey at Basing House finished on Friday in a spray of mud and rain, hailstones and inky cloud. What had promised to be a reasonable day quickly became unworkable, wet and cold. The teams set out for the final day of survey, focusing on completion of the […]

Reblogged from Kristian Strutt:

Click to visit the original post
  • Click to visit the original post
  • Click to visit the original post
  • Click to visit the original post
  • Click to visit the original post
  • Click to visit the original post

The second week of survey at Basing House finished on Friday in a spray of mud and rain, hailstones and inky cloud. What had promised to be a reasonable day quickly became unworkable, wet and cold. The teams set out for the final day of survey, focusing on completion of the magnetometry and resistivity in the area of the New House and outer bailey, and GPR over the outer bailey also.

Read more… 460 more words

Kris Strutt's blog on Day Five of the Week Two geophysics work at Basing House.