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GROUND-PENETRATING RADAR SURVEY ACROSS THE TRANSEPT OF THE KIRK
OF ST NICHOLAS (ABERDEEN) Carmen Cuenca-Garcia
RESULTS & INTERPRETATION

INTRODUCTION
This dissertation project focussed on the application of GPR to
investigate the archaeological remains beneath the transept of the
Kirk of St Nicholas, Aberdeen (fig.1).

Figure 8: Depth
slice from
Grid2 at 0.12m,
showing the
correctlocation
of the
evaluation
trench carried
out by John
Hunter in 1974

Figure 1: Location of the Kirk of St Nicholas (Google Maps 2008)

The discoveries made during
an archaeological excavation
in the East Kirk of St
Nicholas included the east
end of a 10th /11th apsidal
church (fig.2), which
appeared to extend eastwards
underneath the transept area.

10th /11th C
C14 datingConcrete platform

Figure 11: South facing view of Hunter’s evaluation
in 1974 (Aberdeen City Council, Archaeological Unit
photographic archive)

RESULTS & INTERPRETATION SUMMARY
Anomaly
Interpretation
Reflection Type
Description
High amplitude reflection
probably. The anomaly shows a
A1
Former south gable wall
bow tie effect tipically produced by
of the transept
V-shaped trenchesA2
High amplitude reflection
Debris
A3
Point source
A4
Stone burial
Moderate high amplitude
A5
Concrete surface
A6
A7
A8
A9
A10

Pillar/ Early church

High Amplitude

Boulders/Metal objects
Mortar floor
Grave burial

Planar
Vertical shaft

…

Geology

Planar

…

Hunter's archaeological
evaluation trench

Point source

Moderate high amplitude
Moderate lowamplitude
High amplitude

Table 2: Summary of the anomalies detected in the detailed area survey

A5

N

S

A1
Figure 2: Plan view of the architectural phases recorded
during the excavation of the East Kirk of St Nicholas
(adapted from Aberdeen City Council homepage)

Previous archaeological evaluation carried out in the north wing of
the transept and part of the crossing (fig.3) didnot identify the
presence of any structure predating the 12th century, the earliest
structural phase recorded in the current church so far.

A6a

A7
N

S

A8

A10

Figure 12: Profile section from line 5 (pilot survey), showing
the anomaly potentially produced by the original south
gable wall (A1) before it was extended southwards. Note the
red lines highlighting a bow tie effect(fig.13) in the anomaly

In the light of this discovery and of some other lacunae in the
architectural history of the Kirk, further investigation was deemed
to be valuable.
A3

DATA ACQUISITION

Figure 14: Profile section from line 54 (detailed area
survey), showing the truncation of the stratigraphy
by the vertical shaft (fig.15) of a potential grave
burial (A10)

Since theinterior of the transept is still in use, GPR was a suitable
non-invasive technique. Furthermore, the depth and size of the
potential archaeological targets (fig.4), the soil characteristics as
well as the flat floor of the transept provided favourable conditions
to carry out the GPR survey.

A2
A1

A4

After a pilot survey carried out to test the quality of the signal in the
area and toevaluate the limitations of potential surface scattering
and noise problems, a more detailed survey was undertaken. Two
grids were set up in an area of c.16m x 5.75m (fig.5), covering the
crossing and the south wing of the transept.

Figure 15: : Example of stratigraphic truncation
by vertical shaft in a historic cemetery, visible
at A locations (Conyers 2004: 160)

Figure 9: Depth slicefrom Grid 1 & 2,
summarizing the main
anomalies detected at a
depth of 0.57m. Note
the dashed line indicates
the approximate
distance of 15 feet
where the original south
gable wall used to be

Figure 13: Bow tie effect produced by a
V-trench in a modelled reflection profile
(adapted from Conyers 2004: 139)

S

N

A9
Approximately location of John
Hunter’s trench (1974)

N

S...