Archaeologia Islandica - 01.01.2004, Síða 68

John M. Steinberg
Lol (%)
Figure 3. Sample depth against Lol percentage at location 1 of Glaumbœr.
Results
The examination of a profile of a buried
peat bog at the farm of Grófargil yields
some idea of the basic pattems of organ-
ic leaching (Figure 2). The bog is capped
by a prehistoric tephra layer, either Hekla
3 (2900 BP) or Hekla 4 (4500 BP). Two
layers of diatomaceous earth divide the
bog layers. The amount of soil below the
prehistoric Hekla layer would indicate
that this bog was dry for some time
before the settlement of Iceland. Bogs
forming today can have up to 70% Lol
(Johannesson 1960) and so the high of
just under 50 % may indicate some leach-
ing. It would appear that the lowest layer
of bog has had a substantial percentage of
organic content leached out (just over
20% Lol) while the subsoil under the bog
shows enrichment in its upper layers.
The turf wall at Glaumbær (Figure 3)
shows a similar pattem but with much
lower Lol numbers. All of the samples
from this profile were mn twice and both
data points are presented. The turf wall is
just under the Hekla 1 tephra layer (1104
AD). The turf wall below has an organic
content that is about the same as the top-
soil. Peatash contains almost no organic
material. The thin older wall overlain by
the second peatash layer would appear to
be severely leached while the subsoil
immediately below is enriched.
Overall, (see Figure 1) turf has a lower
Lol then the topsoil. The topsoil has an
average of 25 % Lol (SD = 4.6), while
turf has an average of 21.7% (SD = 4.2).
However the upper portions of large turf
walls have higher Lol percentages.
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