Powered by
JSPWiki v2.8.2
g2gp 17-01-2009
View PDF

Previous | Next | Contents


Section 5. Comprehensive Documentation#

5.6 Case study 1: the Cottam project#

by Julian Richards

The presence of Anglian and Anglo-Scandinavian settlements at Cottam, East Yorkshire, was first indicated in 1987 by numerous finds by metal detector users of coins, dress pins, strap ends and other copper alloy artefacts. The Department of Archaeology, University of York, carried out a programme of fieldwork on the site between 1993-1995 which included fieldwalking, geophysical survey and excavation (Richards 1999; 2001). The digital archive has been deposited with the ADS, while the finds and paper archive from the project are deposited with Hull Museum.

The geophysical survey was carried out between October and December 1994. The aim of the survey was to produce a detailed map of sub-surface geophysical anomalies within two sites defined by concentrations of metal finds. The southern concentrations also coincided with a cropmark enclosure. The survey was also to act as a pilot study to assess the relative effectiveness of magnetic and earth resistance techniques in mapping anomalies in this area.

Two survey areas were located in the northern part of the large field to the west of Burrow House Farm. Area 1 (NGR 49760 46674) was situated over the central and eastern part of the concentration of cropmarks forming a large enclosure with several associated smaller enclosures. Area 2 (NGR 49763 46690) was sited over two small sub-rectangular enclosures to the north-east of the larger cropmark site. Both areas were subsequently examined by excavation.

In the field the geophysical data were downloaded from the surveying instruments (an RM4 earth resistance meter and an FM18 fluxgate gradiometer) onto a laptop and processed using Geoplot version 2.02. The processed data were transferred to Surfer version 6 and prepared for presentation.

The digital Archive created by the Cottam project is a research level archive and has been deposited with the ADS. The Archive consists of:

  • 'Level III' reports covering the stratigraphic sequence
  • Fieldwalking, metal detector, geophysical survey reports
  • Specialist reports: animal bone, flint, pottery, plant macrofossils
  • Geophysics data
  • Finds database
  • Context database
  • CAD files, including a rectified aerial photographic plot
  • Colour images of many of the finds

Metadata records were created for the Cottam project as a whole and for individual survey types. Table 3 (below) shows the earth resistance survey documentation for Area 1.

Project Information
Survey nameBurrow House Farm, Cottam
Survey indexArea 1 - COT93 - Earth Resistance - CTR1K
Survey purposeThe aim of the survey was to produce a detailed map of sub-surface geophysical anomalies within two sites defined by concentrations of metal finds. One concentration also coincided with a cropmark enclosure. The survey was also to act as a pilot study to assess the relative effectiveness of magnetic and earth resistance techniques in mapping anomalies in this area.
Report summaryAlthough high resolution magnetic survey proved itself to be the most effective technique in mapping sub-surface archaeological remains, the results of the soil resistance survey clearly provide valuable complementary information on variations in soil compaction as well as identifying features with non-magnetic backfills. The survey provided detailed maps of two sites coarsely defined through aerial photography. The results also indicate basic zonation within these sites based on feature density and variations in soil compaction.
Bibliographic referencesRichards, J.D. 1999 'Cottam: An Anglian and Anglo-Scandinavian settlement on the Yorkshire Wolds' Arch J 156, 1-110

Richards, J.D. 2001 'Anglian and Anglo-Scandinavian Cottam: linking digital publication and archive', Internet Archaeology 10, http://intarch.ac.uk/journal/issue10/richards_index.html

Survey report: http://archaeologydataservice.ac.uk/archives/view/cottam_ba/geophys.cfm
Survey keywordsEarth Resistance, Settlement, Anglian, Anglo-Scandinavian
Spatial coverageArea 1: 497565,466700 to 497644,466779
Administrative areaCottam
StateEast Riding of Yorkshire
CountryEngland
Solid geologyChalk
Drift geologyNot reported
DurationOctober-December 1994
WeatherNot reported
Soil conditionNot reported
Land useArable
Monument typeSettlement
Monument periodEarly medieval
Scheduled Ancient Monument (SAM) numberNot scheduled
SurveyorField Archaeology Specialists, Department of Archaeology, King's Manor, York, YO1 7EP
ClientJulian Richards, Department of Archaeology, University of York, King's Manor, York, YO1 7EP
DepositorJulian Richards, Department of Archaeology, University of York, King's Manor, York, YO1 7EP
Primary archiveArchaeology Data Service: http://archaeologydataservice.ac.uk/archives/view/cottam_ba/
Related archivesDigital archive: http://archaeologydataservice.ac.uk/archives/view/cottam_ba/
Physical archive: Hull Museum
CopyrightJulian Richards
Term listNot reported
Geophysics metadata
Survey typeEarth resistance survey
InstrumentationRM4 Earth Resistance Meter
Probe configurationPA1 twin-electrode probe array
Probe spacing0.5 m
Reasons for choice of survey techniqueThe survey was to act as a pilot study to assess the relative effectiveness of magnetic and earth resistance techniques in mapping anomalies in this area.
Area surveyed0.64 ha
Method of coverageRegular grid, Zigzag
Traverse separation1 m
Line separation1 m
Reading interval1 m
Sampling positionCentre of each 1 m x 1 m square
Data grid size20 m x 20 m
AccuraciesThe location of each measurement point is accurate to 0.1 m with respect to the data grids.
Survey methodologyAll data grids have the same size and resolution. The arrangement of data grids is captured in the file mesh.csv. The survey direction was in positive x-direction, subsequent lines were added in negative y-direction, following a zigzag pattern.
Data treatmentThe raw data were processed using Geoplot version 2.02. This involved the adjustment of any differences in the average background reading between individual survey grids as well as inconsistencies caused by electrode repositioning or changing climatic conditions. The data were interpolated to 0.5 m x 0.5 m to provide a smoother image of the data. The processed data were transferred to Surfer version 6 in which it was prepared for presentation.
Report
Report titleCottam B Geophysical Survey
Report reference numberCOT01
Report authorJustin Garner-Lahire
Report holderField Archaeology Specialists
Geophysics georeferencing
Geophysics coordinate systemBaseline 1 was laid out 2 m west, and parallel with the field boundary to the east, starting 5 m north of the intersection with the wall in the south of the field. This starting point has coordinate (60 m, 0 m) in the geophysics grid, running parallel with its y-axis.
GeoreferencingTwo points of the geophysics grids (A, B) were measured with tapes from two positions in the field (C, D; see map figure): A = (20 m, 60 m); B = (80 m, 60 m); C = SW corner of concrete base of pylon; D = NW edge of northern concrete gate post in eastern field boundary.

AC = 21.4 m; AD = 33.2 m; BC = 22.3 m; BD = 11.4 m.
File description
Explanation of codes used in filenamesct = Cottam
r = Earth resistance
1 = Area 1
Description of file formatsGeoplot 2.02 data grids (.dat, .grd, .his, .sta) and plotmesh (.plm)
Surfer files (.srf)
Date of last modificationApril 1995
Table 3: Cottam Area 1 Earth Resistance Survey Documentation


Acknowledgements

The fieldwork at Cottam was conducted under the auspices of the Department of Archaeology, University of York, and principally funded by the British Academy and the Earthwatch Foundation


Previous | Next | Contents