Archaeologia Islandica - 01.01.2002, Síða 18

Timothy J. Horsley & Stephen J. Dockrill
these remains has never been confirmed
through archaeological evidence (Ibid.
1994, 96-7).
In 1907, Daniel Bruun and Finnur
Jónsson excavated four of the booths and
in the building interpreted as the proba-
ble church (Bruun & Jónsson, 1908;
Jónsson, 1908; and Bruun, 1928). More
recently, in 1986 Margrét Hermanns-
Auðardóttir excavated four trial trenches
in different areas of the site, including an
investigation of the church (Hermanns-
Auðardóttir, 1987).
The remains at Gásir present an ideal
situation for the assessment of geophysi-
cal techniques since the surface features
allow the anomalies detected to be readi-
ly compared with known archaeology.
Gásir poses many archaeological ques-
tions and it was hoped that these surveys
might also provide new information
about the site. Aerial photographs of the
site clearly reveal the large surviving
earthworks, however the question arises
whether the limit of these remains accu-
rately indicates the limit of buried
archaeology. Geophysical surveys might
reveal if activity continues in the areas
outside the earthworks, in addition to
providing archaeological information for
the amorphous earthworks.
The bedrock in the region consists of
basalt strata formed during the Tertiary
period, 5-10 million years ago
(Hallgrímsdóttir 1997, 2), which out-
crops on the higher ground at the site.
The land in which the remains are situat-
ed is given over to horse pasture and is
covered with well-established thufur, up
to 0.5m in height.
A grid, 40m x lOOm, was established
to included the churchyard, a number of
booth remains, and an apparently
'archaeologically quiet' area in between.
In this way the geophysical responses to
a variety of features could be assessed.
Magnetometer results
The results of the magnetometer data
(see Figure 2b for a processed plot) have
revealed a number of interesting anom-
alies. The most striking of these are visi-
ble at the westem end of the survey area,
where a circular positive anomaly con-
taining a rectilinear positive anomaly has
been detected, coinciding with the
remains of the church and churchyard.
Other intense anomalies in this region
correspond to the areas where the basalt
bedrock outcrops, and are interpreted as
being of geological origin.
The area of booths also reveals itself
as an area of broader effects, with some
intense positive anomalies following reg-
ular shapes. This contrasts to the zone
between the booths and churchyard
where it is still quite magnetically noisy,
but the anomalies are less intense and
small scale.
Figure 2c presents an interpretation of
the main anomalies recorded. The bank
of the churchyard boundary appears as a
positive linear magnetic anomaly, in
some places there are two of these linear
anomalies parallel to each other. These
might be the response to magnetic rocks
within the bank, possibly as stone fac-
ings, which have not previously been
recorded. Similar anomalies are seen in
the area corresponding with the church
structure. As concluded by Bruun and
Hermannsdóttir, the church was con-
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