RAF Lakenheath Transient Lodging Facility ERL 127
ARCHAEOLOGICAL MONITORING REPORT
______________________________________ RAF Lakenheath Transient Lodging Facility ERL 127 A REPORT ON THE ARCHAEOLOGICAL MONITORING, 2003 (Planning app. no. F/2001/115)
Jo Caruth Field Team Suffolk C.C. Archaeological Service © March 2006 Lucy Robinson, County Director of Environment and Transport Endeavour House, Russel Road, Ipswich, IP1 2BX
______________________________________ SCCAS Report No. 2006/39
i
Contents List of Figures List of Contributors Acknowledgements Summary SMR information
Introduction Methodology Results Environmental evidence Discussion and conclusion Reference Appendix 1: Soil micromorphology
List of Figures 1. 2. 3. 4.
Site location Photographs of the ploughlines Location of the ploughlines Aerial photograph, c.1946
i
ii
List of Contributors All Suffolk C.C. Archaeological Service unless otherwise stated. Jo Caruth Val Fryer Dr Richard Macphail Dr Jean-Luc Schwenninger
Senior Project Officer Environmental specialist, Freelance Soil Micromorphologist, Freelance Research laboratory for Archaeology and history of Art, University of Oxford
Acknowledgements This project was funded by MOD Defence Estates and the archaeological work specified by Jude Plouviez (Suffolk County Council Archaeological Service, Conservation Team). The fieldwork was carried out by Jo Caruth and David Gill from Suffolk County Council Archaeological Service, Field Team. A visit to the site was made by Dr Jean-Luc Schwenninger from the Research Laboratory for Archaeology and the History of Art (RLAHA) to sample for optically stimulated luminescence dating (OSL).
Summary Archaeological monitoring was carried out at RAF Lakenheath during the construction of the new Transient Lodging Facility. This revealed the presence of some well preserved ploughlines which have the potential to contribute to the landscape and agricultural history of Breckland. These have been positively dated using Optically Stimulated Luminescence at 160 years old ( 80years. The natural yellow sand beneath these was dated as c.23,000 years old.
SMR information Planning application no.
F/2001/115
Date of fieldwork:
10th April 2003
Grid Reference:
TL 7358 8051
Funding body:
MOD DE (USF)
ii
1
Introduction Archaeological monitoring was carried out between July and September 2003 during the construction of the new Transient Lodging Facility at RAF Lakenheath. The site lies at TL 7358 8051 on the east side of the Base. Evaluation in 2003 (Caruth 2003) revealed a low density scatter of undated features, some of which were interpreted as tree pits. The closest dated archaeological deposits are Middle Saxon occupation c.170m and Early Saxon settlement and cemetery c.350m west of the site.
ERL 127 The Site
0
500
1,000
metres
©Crown Copyright. All Rights Reserved. Suffolk County Council Licence No. 100023395 2006
Figure 1. Site location
Methodology Monitoring visits were made during the construction groundworks. The site strip, excavations for footings and drainage trenches were observed in a series of short visits during July to September 2003. The only discovery of note was that of some ploughmarks in the southern end of the site, seen in service trenches. These were photographed, recorded in section at 1:20 and 1:2 and bulk sampled. In addition samples were taken for soil micromorphology and Optically Stimulated Luminescence dating. The approximate extent of these, as indicated by their presence in trenches was plotted. The site is recorded under the County Sites and Monuments Record Parish number ERL 127. The site archive is kept in the Archive stores of SCCAS at Bury St Edmunds.
1
2
Figure 2. Photographs of the ploughlines
2
3
Results The only feature identified during this monitoring was a series of north-south aligned ploughmarks (Fig. 2). These were found c. 35cm below the current ground surface lying under c.15cm of modern redeposited material and c.20cm of a mid red-brown sand interpreted as a buried topsoil or ploughsoil. The ploughlines cut into yellow sand natural and each ploughmark was c.35-40cm long and c.15cm thick, although soil disturbance can be seen over a depth of up to c.27cm. The most distinctive mark was a dark brown sand band which is probably inverted turf, and a gravelly sand deposited over and around this is probably inverted natural sand from which the finer grains have been eroded by windblow. At the lower edge of the inverted ‘turf’, charcoal fragments could be seen and these may indicate vegetation burning just prior to ploughing. The ploughmarks were undated, and nor were any of the deposits around them. The ploughlines were seen in three service trenches in the south-west corner of the site, but were not noticed under the building to the north and east. Although conditions for identifying deposits were not always ideal, these marks were so distinctive that it is probable that, had they been present, they would have been seen in at least some of the excavations deep enough to expose them. However it is not possible to be certain that this indicates a limit to the ploughing as opposed to fortuitous survival in one area.
New building position
Ploughlines seen in trenches
Suggested extent of ploughlines
0
25
50
metres ©Crown Copyright. All Rights Reserved. Suffolk County Council Licence No. 100023395 2006
Figure 3. Location of ploughlines
3
4
Environmental evidence Optically Stimulated Luminescence A sample of the ploughlines and the sediment around them was taken for dating using Optically Stimulated Luminescence (OSL). This dating method records the amount of luminescence (light) emitted on illumination due to the release of stored energy accumulated from natural radioactivity. When a sediment is exposed to sunlight all previously acquired light is removed, but when it is sealed from sunlight the luminescence accumulates in response to the radiation received during the burial period. The level of OSL observed in ancient samples is therefore dependent on the absorbed radiation, and can be related to the time elapsed since it was last illuminated. The following is an extract from the results of the OSL dating provided by Dr Jean-Luc Schwenninger. ‘The basal sand which forms the parent material is circa 23000 years old with two samples (OSL1 and OSL2) providing near identical dates (23250 +/- 1860 and 23560 +/- 1370). Sample OSL 3 which was taken from one of the dark plough marks suggests a really young age of circa 160 +/- 80 years and sample OSL 4 collected from the overlying topsoil gives a similar young age of circa 230 years.’
Soil Micromorphology by Richard Macphail A 200mm long monolith was collected from the section through one of the ploughmarks in order to assess the sample for soil micromorphology. It was only intended to pursue this analysis if an absolute date could be established for the ploughing. The full report is contained in Appendix 1.
Plant Macrofossils by Val Fryer A single sample was taken from the ploughlines for plant macrofossil analysis in the hope that diagnostic plant macrofossils or material suitable for dating may have been recovered. The sample was processed by manual water flotation/washover, and the flot was collected in a 500 micron mesh sieve. The dried flot was scanned under a binocular microscope at magnifications up to x 16. Modern contaminants including fibrous roots, seeds, arthropods and fungal sclerotia formed the bulk of the material recovered, along with small pieces of black tarry material and coal. Although a small number of charcoal fragments were recorded, it is unclear whether these were contemporary with the plough marks, or intrusive from the overlaying soil horizon. As the contemporaneity of the charcoal fragments and plough marks cannot be categorically proved, and as the quantity of material recovered is very low (
______________________________________ RAF Lakenheath Transient Lodging Facility ERL 127 A REPORT ON THE ARCHAEOLOGICAL MONITORING, 2003 (Planning app. no. F/2001/115)
Jo Caruth Field Team Suffolk C.C. Archaeological Service © March 2006 Lucy Robinson, County Director of Environment and Transport Endeavour House, Russel Road, Ipswich, IP1 2BX
______________________________________ SCCAS Report No. 2006/39
i
Contents List of Figures List of Contributors Acknowledgements Summary SMR information
Introduction Methodology Results Environmental evidence Discussion and conclusion Reference Appendix 1: Soil micromorphology
List of Figures 1. 2. 3. 4.
Site location Photographs of the ploughlines Location of the ploughlines Aerial photograph, c.1946
i
ii
List of Contributors All Suffolk C.C. Archaeological Service unless otherwise stated. Jo Caruth Val Fryer Dr Richard Macphail Dr Jean-Luc Schwenninger
Senior Project Officer Environmental specialist, Freelance Soil Micromorphologist, Freelance Research laboratory for Archaeology and history of Art, University of Oxford
Acknowledgements This project was funded by MOD Defence Estates and the archaeological work specified by Jude Plouviez (Suffolk County Council Archaeological Service, Conservation Team). The fieldwork was carried out by Jo Caruth and David Gill from Suffolk County Council Archaeological Service, Field Team. A visit to the site was made by Dr Jean-Luc Schwenninger from the Research Laboratory for Archaeology and the History of Art (RLAHA) to sample for optically stimulated luminescence dating (OSL).
Summary Archaeological monitoring was carried out at RAF Lakenheath during the construction of the new Transient Lodging Facility. This revealed the presence of some well preserved ploughlines which have the potential to contribute to the landscape and agricultural history of Breckland. These have been positively dated using Optically Stimulated Luminescence at 160 years old ( 80years. The natural yellow sand beneath these was dated as c.23,000 years old.
SMR information Planning application no.
F/2001/115
Date of fieldwork:
10th April 2003
Grid Reference:
TL 7358 8051
Funding body:
MOD DE (USF)
ii
1
Introduction Archaeological monitoring was carried out between July and September 2003 during the construction of the new Transient Lodging Facility at RAF Lakenheath. The site lies at TL 7358 8051 on the east side of the Base. Evaluation in 2003 (Caruth 2003) revealed a low density scatter of undated features, some of which were interpreted as tree pits. The closest dated archaeological deposits are Middle Saxon occupation c.170m and Early Saxon settlement and cemetery c.350m west of the site.
ERL 127 The Site
0
500
1,000
metres
©Crown Copyright. All Rights Reserved. Suffolk County Council Licence No. 100023395 2006
Figure 1. Site location
Methodology Monitoring visits were made during the construction groundworks. The site strip, excavations for footings and drainage trenches were observed in a series of short visits during July to September 2003. The only discovery of note was that of some ploughmarks in the southern end of the site, seen in service trenches. These were photographed, recorded in section at 1:20 and 1:2 and bulk sampled. In addition samples were taken for soil micromorphology and Optically Stimulated Luminescence dating. The approximate extent of these, as indicated by their presence in trenches was plotted. The site is recorded under the County Sites and Monuments Record Parish number ERL 127. The site archive is kept in the Archive stores of SCCAS at Bury St Edmunds.
1
2
Figure 2. Photographs of the ploughlines
2
3
Results The only feature identified during this monitoring was a series of north-south aligned ploughmarks (Fig. 2). These were found c. 35cm below the current ground surface lying under c.15cm of modern redeposited material and c.20cm of a mid red-brown sand interpreted as a buried topsoil or ploughsoil. The ploughlines cut into yellow sand natural and each ploughmark was c.35-40cm long and c.15cm thick, although soil disturbance can be seen over a depth of up to c.27cm. The most distinctive mark was a dark brown sand band which is probably inverted turf, and a gravelly sand deposited over and around this is probably inverted natural sand from which the finer grains have been eroded by windblow. At the lower edge of the inverted ‘turf’, charcoal fragments could be seen and these may indicate vegetation burning just prior to ploughing. The ploughmarks were undated, and nor were any of the deposits around them. The ploughlines were seen in three service trenches in the south-west corner of the site, but were not noticed under the building to the north and east. Although conditions for identifying deposits were not always ideal, these marks were so distinctive that it is probable that, had they been present, they would have been seen in at least some of the excavations deep enough to expose them. However it is not possible to be certain that this indicates a limit to the ploughing as opposed to fortuitous survival in one area.
New building position
Ploughlines seen in trenches
Suggested extent of ploughlines
0
25
50
metres ©Crown Copyright. All Rights Reserved. Suffolk County Council Licence No. 100023395 2006
Figure 3. Location of ploughlines
3
4
Environmental evidence Optically Stimulated Luminescence A sample of the ploughlines and the sediment around them was taken for dating using Optically Stimulated Luminescence (OSL). This dating method records the amount of luminescence (light) emitted on illumination due to the release of stored energy accumulated from natural radioactivity. When a sediment is exposed to sunlight all previously acquired light is removed, but when it is sealed from sunlight the luminescence accumulates in response to the radiation received during the burial period. The level of OSL observed in ancient samples is therefore dependent on the absorbed radiation, and can be related to the time elapsed since it was last illuminated. The following is an extract from the results of the OSL dating provided by Dr Jean-Luc Schwenninger. ‘The basal sand which forms the parent material is circa 23000 years old with two samples (OSL1 and OSL2) providing near identical dates (23250 +/- 1860 and 23560 +/- 1370). Sample OSL 3 which was taken from one of the dark plough marks suggests a really young age of circa 160 +/- 80 years and sample OSL 4 collected from the overlying topsoil gives a similar young age of circa 230 years.’
Soil Micromorphology by Richard Macphail A 200mm long monolith was collected from the section through one of the ploughmarks in order to assess the sample for soil micromorphology. It was only intended to pursue this analysis if an absolute date could be established for the ploughing. The full report is contained in Appendix 1.
Plant Macrofossils by Val Fryer A single sample was taken from the ploughlines for plant macrofossil analysis in the hope that diagnostic plant macrofossils or material suitable for dating may have been recovered. The sample was processed by manual water flotation/washover, and the flot was collected in a 500 micron mesh sieve. The dried flot was scanned under a binocular microscope at magnifications up to x 16. Modern contaminants including fibrous roots, seeds, arthropods and fungal sclerotia formed the bulk of the material recovered, along with small pieces of black tarry material and coal. Although a small number of charcoal fragments were recorded, it is unclear whether these were contemporary with the plough marks, or intrusive from the overlaying soil horizon. As the contemporaneity of the charcoal fragments and plough marks cannot be categorically proved, and as the quantity of material recovered is very low (
