archaeological gpr survey in a church
TRANSCRIPT
Data Collected using GSSI’s SIR® 3000
Geophysical Survey Systems, Inc.
Historical Archaeology GPR Survey St. Mary Redcliffe Parish Church
Photos and Data Courtesy:
Benjamin & Beauchamp Architectswww.b2architects.com
Sandberg LLP, United Kingdomwww.sandberg.co.uk
St. Mary Redcliffe is an Anglican parish church located in Bristol, England. The church dates from the twelfth century and has been a place of
worship for over 800 years. It is one of the finest examples of Gothic architecture in England. Queen Elizabeth I, on her visit in 1574, described the church as “the fairest, goodliest, and most famous parish church in England.”
In early 2014, the Church hired Sandberg, a leading NDT consultancy, to find a nondestructive means to
survey areas of the church with two objectives in mind:
• Establish the depth and extent of any subsurface structures and graves in the area of land to the north of the church
• Establish the construction build-up beneath the North aisle, Inner and Outer North Porch of the church, and any graves therein
Sandberg determined that ground penetrating radar would be the best survey method to detect the subsurface features likely to indicate graves as well as any unknown subsurface infrastructure.
Sandberg used a SIR® 3000 with a 270 MHz and 400 MHz antenna, giving a range of depth and resolution options. The external ground and floor areas were scanned on regular orthogonal grids with scan lines at 0.5 and 1m on center.
The Project
Project Description
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11.05.2014
A number of features, voids and anomalies were detected in the external area to the north of
the church. The location, extent and depth of these were plotted on a CAD drawing. Anomalies are defined as areas within the data significantly different from the surrounding area. Although GPR is not able to confirm the exact nature of detected features, it is likely that some are old foundations.
Exterior Survey
Interior SurveyI n s i d e t h e c h u r c h several different forms of construction were
detected. In the north aisle the floor slab changed to a suspended slab with vaults below (reference data image). In addition an area of interest, later identified as a crypt, was detected (reference data image).
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