Archaeologia Islandica - 01.01.2007, Side 65

Ancient ironmaking in Iceland, Greenland and Newfoundland
exploited, a practice which would have
led to serious deterioration. As long as the
bloomery process was in use, the value
of the forests was linked to charcoal pro-
duction. Birch suitable for this grew up
from the trunks left after cutting and also
from fresh shoots. Only towards the end
of the 18th century an attempt was made
to widen the grazing fields for sheep
by felling trees. But the farmer in Vagl-
ir experienced soil erosion and stopped
such attempts (Þorbergur Hjalti Jónsson
pers.comm.). A comprehensive account
of development during recent centuries is
given by Bjarnason (1980). Fnjóskadalur
lies far from active volcanoes. Still the
layers of whitish ash from a Hekla erup-
tion 3000 years ago and black ash from
Vatnajökull in the year 1477 are notice-
able. The distance to these volcanoes is
some 150-200 km.
The author also had a chance
to visit the area around Ormstaðir near
Egilsstaðir in the east and the valley
Þjórsárdalur in the south. In Ormstaðir
an ironmaker’s smithy (rauðasmidja) has
been excavated (Friðriksson & al 1992).
In the desolate plateau near þjórsá cov-
ered by black volcanic ash the site of the
farm Sandartunga is marked. This farm
was finally abandoned after a destruc-
tive eruption in the year 1693 (Stenberger
1943). Now only black bloomery slag and
some roof tiles seem to be the clearest
evidence of human activity (see later).
The finds in Fnjóskadalur.
Three slag heaps near the farm Belgsá
(abandoned in 1949) and at the farms
Lundur and Viðivellir were visited in the
years 1996, 1998 and 2001. At the Belgsá
site the slag heap is - due to wind erosion
- free from any soil and vegetation, so
that simple visual examination reveals
possible remains from constructions and
the character of the refuse. At Lundur the
grass-covered enormous slag heap gave
room to a goat stable some 100 years ago.
The volume of slag can only be given as
“large”. At Viðivellir the area covered by
slag appears to cover about 1000 m2with
a height of about 1 m. The volume of slag
is carefully estimated as 500m3. The bulk
density of medieval slag in a heap is
roughly 1000 kg/m3 (Martens et al. 1988).
It therefore represents at least 500 tons.
Ore formation is visible in creeks and
ditches at Lundur and Viðivellir. The slag
heap at Belgsá is oval, measuring some
10 x 15 m with a maximum height of
0.8-1 m (Figure 5). The total volume
appears to be at least 30 m3. A square,
broken flat stone with a hole measuring
6x6 cm and also a little depression
deserves special attention (also mentioned
by Nielsen 1926). It appears to have been
the base of an anvil. The slag heap con-
sists mainly of “tap slag”, with a charac-
ter identical to slag from the same period
in Norway: It is black and dense, with a
worm-like smooth pattern on top and a
rough bottom with impressions of gravel.
It was clearly tapped into a groove in
front of the furnace. However, no trace of
any furnace could be observed. Three
charcoal pits were found at a distance of
50 m from the slag heap.
In Norway the furnaces of this
period had an inner diameter of 25-30 cm
and were made from clay with grog (sand)
added. This “cylinder” was positioned
between flagstones on three sides. Such
stones are rarely found as they often were
removed and used for new purposes, such
as house construction. However, pieces
of red-burnt clay are always found in the
slag heaps. In Iceland the fumaces must
have been made from some other mate-
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