Ladybridge Farm: Archaeological Evaluation
3.0 Evaluation Strategy
This programme of archaeological evaluation was designed and executed as a staged investigative programme, wherein the results of the early stages were used to inform the detailed design of subsequent stages. A variety of non-invasive and invasive investigative techniques were employed including fieldwalking, geophysical survey, auger survey, test pitting and evaluation excavation. In addition to the staged programme, existing background information consisting of plotted cropmarks derived from aerial photographs and former field boundaries digitised from historic maps, were also used to inform the evaluation strategy and the interpretation of results. Additionally, the results of previous archaeological investigations in the area also provided valuable background information, along with many years of relevant fieldwork experience gained at Nosterfield Quarry by members of the FAS Ladybridge Farm evaluation team.
This staged programme allowed specific areas to be targeted most effectively and with the most appropriate technique. Where a sample of the site was investigated using a specific technique, this was undertaken on a selective, rather than on a random basis. Accordingly, areas deemed of higher potential, based on the results of preceding investigation, were targeted for more intensive study. Due to the variation in land-use, ground conditions and archaeological visibility, individual investigative techniques were applied only to areas of the site where, based on professional judgement, the technique was considered to be suitable.
In the case of invasive intervention, a reasonable balance has been achieved between the need for information, and the need to minimise damage to the archaeological resource. Test pits were designed to establish whether the ploughsoil within the application area contained a significant vertical distribution of lithic material. The majority of the test pits were undertaken within the area of subsequent evaluation trenches in order to test the ploughsoil in advance of disturbance, and also to provide a guide during machine excavation of the evaluation trenches. The machine excavated evaluation trenches represent a 2% sample of the application area. While the position of the trenches was determined partly by areas of higher potential identified during the earlier stages of the evaluation, a balance was struck whereby the trenching regime also provided a reasonable coverage of the site. Elongated rectangular trenches were employed to improve the probability of identifying boundary features and defining geological variation.
3.1 Zonation
Due to the size of the site and the variation in land use, the area of investigation was divided into six zones for the purposes of project management and recording (Figure 7, Table 1). This approach provided a means of assessing the likely variation in archaeological visibility, as well as predicting the relative success of individual investigative techniques.
3.2 Interventions
In order to create a structured and consistent project archive from data-sets derived from the application of different techniques of investigation, each separate operation was assigned an intervention number (Table 2). An intervention was defined either by an area examined or by the application of a technique.
3.3 Survey
A site grid was established for recording purposes, and all boundaries and features within and around the area of investigation were surveyed using a total station theodolite. The resulting map was then rectified to the Ordnance Survey National Grid. A series of survey stations were then set out around the site to facilitate accurate surveying and recording during all phases of the evaluation programme. All co-ordinates and alignments expressed in this report refer to the Ordnance Survey National Grid; all heights are expressed in metres above ordnance datum (AOD).
3.4 Fieldwork Constraints
The site is currently a working farm. In order to limit the destruction of crops and disruption to the farming regime, stages of the evaluation were undertaken during periods when damage and disruption could be minimised. This resulted in stages of the evaluation programme being undertaken at different times in different zones of the site, and in one instance, it was necessary to undertake stages of the investigation out of the logical sequence.
Certain areas of the site became inaccessible due to the presence of surface water during wet weather (Zones E and F). Investigation of these areas was therefore undertaken after long spells of dry weather.
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