Archaeologia Islandica - 01.01.2002, Blaðsíða 22

Timothy J. Horsley & Stephen J. Dockrill
tlement of Iceland, the fírst bishopric was
founded at Skálholt in 1056 for South
Iceland, and soon a second at Hólar in
1109 for North Iceland.
When the modern cathedral building
was constructed in 1954 there was great
archaeological interest in the remains of
the medieval Cathedral (Olafsson 1988,
7-9), yet very little archaeological work
has been undertaken into the associated
farm at Skálholt. A 'map' of the Cathedral
and farm complex dating to 1784 sur-
vives (see Figure 3), although compari-
son with the few features that are still vis-
ibly today reveals that it is not an accu-
rate plan. However, this plan does pro-
vide an indication as to the farm size,
number of buildings, and even details the
use of each room at that time.
Geophysical surveys were undertak-
en immediately to the south of the mod-
em cathedral building, over land owned
and maintained by the Skálholt Church
Trust.
The bedrock of this region is
Pleistocene lava (Hallsdóttir 1987, 3),
however it is not clear which tephra lay-
ers are present at the site.
The documentary evidence for the
farm makes Skálholt another ideal site
for an assessment of archaeological
prospection techniques. Today only the
two sunken streets and huge midden
mounds are visible on the surface, yet
particular buried remains can be expect-
ed allowing a useful evaluation with the
additional benefít of providing new
information about the history of Skálholt.
Magnetometer results
Figure 4 shows that in general, a high
level of small-scale magnetic noise has
been detected, interpreted as being due to
individual buried rocks, possibly as a
rubble spread from buildings which once
stood in this area. Not visible in the data
are the intense regular anomalies detect-
ed at many other sites (see Gásir (Fig. 2b)
and Hofstaðir (Fig. 6a)) and attributed as
the magnetic response to the strong geo-
logical thermoremanence. This may be
due to a thick layer of wind blown
deposits on top of the bedrock, thereby
causing a greater distance between the
parent material and the surface and dra-
matically reducing the anomaly intensi-
ties. Off-site augering had not hit
bedrock at the auger's maximum depth of
1.15m. It is believed that this reduced
geological input has allowed a number of
positive magnetic anomalies to stand out
from the background noise and look dis-
tinctly like the expected responses to
buried archaeological features. These
magnetic anomalies are the first seen
during this assessment in Iceland, which
differ from the responses to geology or
rocks, and are therefore very interesting.
Many dipole anomalies are still present,
but there are positive and negative linear
anomalies in addition to broader areas of
positive magnetisation. Due to the fact
that the general level of magnetic noise is
still fairly high, it might be expected that
strongly magnetic features, such as accu-
mulations of bumt material, are the cause
of these anomalies. This hypothesis is
backed up by a soil sample collected at a
depth of 5cm in one of the positive fea-
tures. This consisted almost entirely of
peat ash, and later laboratory measure-
ments produced an enhanced magnetic
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