Definition and scope of the specification
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Definition and scope of the specification |
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A plan by Western Aggregates Ltd (RMC Group) to construct a batching plant, plant area and gravel quarry between the Eggington Brook and the River Trent (NGR SK 277 274) was preceded by a programme of soil stripping and trial trenching which revealed archaeological deposits in two areas of the site; the plant site and an area designated for mineral extraction, the Phase 1 site.
The archaeological deposits were found buried beneath alluvial clays. Some deposits overlay further alluvial clays whilst others overlay clayey gravels. The westernmost part of the site (Zone 6) was stripped of topsoil and alluvium down to the gravels exposing archaeological features. Food Vessel type pottery was found in a pit-like feature (context 2). Further trial trenching showed archaeological deposits to be present in most parts of the development area.
The low-lying position of the site and the high water table resulted in opened areas being flooded by up to 0.50m of standing water. The gravels and clayey gravels lying below the alluvial clays showed a marked tendency to rip when machined. In Zone 6 truncation of the deposits by machine and damage by dumper truck tyres resulted in an undulating surface over the western part of the site. When exposed the alluvial clays had a tendency to bake hard and crack.
Although some features were easily identified by the dark fills containing abundant charcoal, others were less visible. In one trench (at the eastern end of Zone 4) a linear deposit of clay similar to the alluvial clay that had been removed by machine was investigated and found to fill a ditch like feature. The clay sealed a charcoal rich fill.
The very clayey (and, without pumping, waterlogged) nature of the substrata also resulted in either extremely soft and sticky conditions when wet or extremely tough conditions when dried with a short optimal period between where hoeing or shovel scraping yielded useful results.
Areas of higher archaeological potential were defined on the basis of the trial trenching, limited cleaning and excavation of features.
Three zones (2, 4 and 6) were identified as requiring controlled excavation following some further machine stripping. The remaining zones (1, 3 and 5) are, at the time of writing, being stripped to the top of gravels. In areas permitted for mineral extraction it is intended that the clayey gravels should also be removed. In these areas a low level watching brief will be employed to record archaeological information. Features containing Beaker pottery and a well preserved keyhole shaped oven have been recorded in Zone 1 to the east of Zone 2.
The archaeological deposits comprise cut features, including gullies and post holes and surface features comprising spreads containing artefacts, which may constitute occupation layers, burnt areas and hearths. The archaeological levels recorded to date span between 42.90m and 42.42m OD. There is perhaps a broad trend of the highest archaeological deposits overlying the gravels and the lowest alluvial clays. In Zones 2 and 4 the deposits are sealed and well preserved.
The highest archaeological deposits are within Zone 2 between 42.79 and 42.90m OD and consists of features cutting gravels and some possible in situ layers.
The level of activity in Zone 6 is less well defined than in other areas, as alluvium and some gravels were removed by the contractors stripping; surviving levels are between 42.63 and 42.75m OD.
Some burnt areas have been recorded within trenches in Zone 3 high within alluvial clay, at 42.76 and 42.79m OD. Similar deposits within Zones 1 and 5 lie between 42.60 and 42.47m OD.
Features cutting gravels and clays are present in Zone 4 between 42.56 and 42.63m OD. Material identified to date includes Food Vessel type pottery from the south of Zone 6 and centre of Zone 2, Collared Urn from Zone 4 and sherds of Beaker type from Zone 1. Worked flints have been recovered from a number of layers and feature fills. All stratified flint and some stratified pottery are being three-dimensionally recorded on a judgemental basis.
The watching brief and evaluation has located a spread of features some of which are associated with Late Neolithic - Early Bronze Age flint and pottery. This includes a polished flint axe and sherds of Beaker, food vessel and collared urn type pottery. The material and features are widely spread but three zones of potential have been identified. If this proves to include well preserved, stratified Neolithic - Early Bronze Age settlement evidence, as appears possible, it may be of national importance.
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Zone |
Action |
Area |
Approach |
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1 |
Watching brief |
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Low level watching brief |
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2 |
Excavation |
0.78 ha |
Targeted cleaning, recording and excavation |
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3 |
Watching brief |
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Low level watching brief |
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4 |
Excavation |
0.16 ha |
Targeted cleaning, recording and excavation |
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5 |
Watching brief |
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Low level watching brief |
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6 |
Excavation |
1.16 ha |
Targeted cleaning, recording and excavation |
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Table 1. Zones and proposed archaeological strategy
The specific objectives of the excavation will be:
The overburden will be removed in spits by machine with toothless ditching bucket (or similar) under full supervision, until archaeological deposits or undisturbed substrata are encountered. Targeted areas within each zone will be then be examined by hand cleaning and any archaeological deposits located will be planned. Samples of any archaeological deposits located will be hand excavated. Measured drawings of all archaeological features will be prepared at a scale of 1:20 and tied into an overall site plan of 1:100. All plans will be tied into the National Grid. Any archaeological deposits located will be hand cleaned and planned as appropriate. Samples of any archaeological deposits located will be hand excavated. Measured drawings of all archaeological features will be prepared at a scale of 1:20 and tied into an overall site plan of 1:100.
Hand cleaning of the surface will be used to:
Archaeological deposits will be excavated and recorded as appropriate to establishing the stratigraphic and chronological sequence of deposits, recognising and excavating structural evidence and recovering economic, artefactual and environmental evidence. Particular attention will be paid to the potential for the survival of buried palaeosols.
All excavated sections will be recorded and drawn at 1:10 or 1:20 scale, levelled and tied into the Ordnance Survey datum. Spot heights will be taken as appropriate.
Any human remains encountered will only be removed under a Home Office Licence and in compliance with relevant environmental health regulations.
In view of the different conditions prevailing in the different zones, different approaches are suggested for zones 2 and 4 to that suggested for Zone 6:
The features observed in Zone 6 to date, include hearths (discrete areas of concentrated burnt stone and charcoal), other pit like marks, gullies (often in groups of three), stakeholes and also some extensive areas of burning that appear more as positive features. Some of these areas appear to cut and be sealed by alluvial clay.
Approximately 0.31 ha across the northern end of Zone 6 is covered by a thin spread of alluvium. Although Western Aggregates do not propose to remove this at this stage archaeological deposits can be seen very close to the surface and will be vulnerable to any tracking even if covered. To enable the relationship between Zones 2 and 6 to be established as required by the County Archaeologist it is suggested that an area of c. 800 sq. m is machine stripped.
At the southern extent of Zone 6 some dark features (hearths, pits, gullies) are currently visible within this area; the deposits are soft and fragile having been sitting below surface water for several months. These deposits will be damaged by trampling.
It is suggested that areas around those features already exposed are hand cleaned followed by recording and sample excavation to characterise their nature, extent and provide dating information.
It is also envisaged that in order to fully recognise the extent of deposits where they are dense on the very clayey gravels in Zone 6 it will be necessary to water and cover areas with tarpaulins or similar to adequately manage the archaeology.
Assessment of the results of this will enable further areas within Zone 6 to be cleaned more methodically to enable a fuller picture to be gained.
It is proposed to work on Zone 6 from the south-west to the north-east. It is aimed to hand clean c. 30% of the area appropriate to providing the information detailed in 4.8.
The areas have had topsoil removed by contractor and have been trenched as part of the archaeological work.
Careful machining will yield a less undulating surface than has been achieved by the contractors volume strip of Zone 6. Features recorded in Zone 2 will probably for the most part be cut through gravels alone. Again on the basis of those features excavated to date, there is a mix of fill types with some being grey and organic and others more sterile. The butt ends of some possibly curvilinear like features have been recorded and the presence of structures is suggested for some of this zone.
Other parts of Zone 2 are more complicated notably a layer of material partly disturbed by contractors stripping and not clearly of alluvial type. Sherds of unabraded Food Vessel type pottery were recovered from within the layer.
In view of its topographical location and the structural and artefactual evidence it is possible to predict that Zone 2 is a focus of Neolithic-Bronze Age activity. In view of this it is aimed to hand clean c. 50% of the zone (following machine stripping) with the visible deposits being specifically targeted.
Deposits including hearth type features, sealed within alluvial clays and gullies and pits cut through clayey gravels have been partly recorded. One feature investigated was found to contain sherds of Collared Urn in its upper levels which do not appear to be a disturbed burial deposit. Following machine stripping it is aimed to hand clean c.30% of the area, with the visible deposits specifically targeted.
To avoid tracking damage it is proposed to remove the alluvium down to the archaeological levels by controlled machine stripping using two mechanical excavators. A sixteen ton tracked excavator will strip from the centre of Zone 2 with a twenty-two ton long armed excavator to remove spoil and dump it outside the area, north and south. The same method will be used for Zone 4 with the spoil placed to the north and Zone 6 with spoil placed to the north and south-east. The three areas could be stripped using this method over a period of ten days.
The stripping will be carefully monitoring and appraised; a large area of exposed alluvial clay can become unworkable if allowed to become either waterlogged or dried out. If appropriate two archaeologists in addition to the archaeologist supervising the machine stripping will clean the machined surface with shovels.
Individual descriptions of all archaeological strata and features excavated or exposed will be entered onto prepared pro-forma recording sheets.
A site location plan based on the current Ordnance Survey 1:1250 map, enlarged to 1:500 (reproduced with the permission of the Controller of HMSO) will be prepared. This will be supplemented by a plan at 1:200 (or 1:100), which will show the location of the areas investigated.
Some record of the full extent in plan of all archaeological deposits encountered will be made and related to the Ordnance Survey grid. Elevations and sections of individual layers of features should be drawn where possible. The OD height of all principal strata and features will be calculated and indicated on the appropriate plans.
An adequate photographic record of the investigations will be prepared. This will include black and white prints and colour transparencies illustrating in both detail and general context the principal features and finds discovered. The photographic record will also include 'working shots' to illustrate more generally the nature of the archaeological operation undertaken. The records will be compiled and fully checked during the course of the excavation.
A report on the fieldwork will be provided following analysis of the records and materials. The scope of this will be subject to a separate design specification following the fieldwork. A provisional strategy for post excavation work is discussed below.
Experience has shown that a full assessment, carried out to the standards established by English Heritage (1991) can, in some cases, lead to higher costs. In view of the budgetary constraints for this project a rapid assessment and archive enhancement period is proposed (c. 15% of the fieldwork costs). Analysis should be targeted to producing an integrated report. Specialist contributions are likely to be required for the artefacts, radiocarbon dating and environmental information. While artefact quantities are unlikely to be high the potential for good preservation may require particular techniques not normally included to be considered for example micro-wear analysis. There is also the potential for good survival of biological information. A budget of c. 60% of the fieldwork costs might be anticipated.
A full copy of the archive as defined in the Guidelines for the preparation of excavation archives for long-term storage (UKIC 1990) and Standards in the museum care of archaeological collections (MGC 1992) and Guidelines for the preparation of site archives and assessments for all finds (other than fired clay objects) (RFG/FRG 1993) will be presented to within six months of the completion of fieldwork. This archive will include all written, drawn and photographic records relating directly to the investigations undertaken.
A micro-copy of the site archive and report will be sent to the National Monuments Record. Any disk-based data will be provided for Derbyshire Sites and Monuments Record.
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