Archaeologia Islandica - 01.01.1998, Side 131

Archaeological Sediments and Site Formation at Hofstaðir, Mývatn, NE-Iceland
incorporation of soil organic matter
into the silts (horizons coloured
10YR2/1 and 7.5YR3/2). This strati-
graphic unit provides indication of en-
vironmental conditions prior to
cultural activity and suggests fluctuat-
ing periods of land stability and insta-
bility.
Immediately above the lowest
stratigraphic unit is Context 4, a
midden-like deposit which may act as
a horizon marker since it seems to
underlie the principal cultural deposits
in Area D, and overlies the midden
deposits in Area G. The thickness of
this deposit averages 2 cm, and in
places it divides into two layers
separated by a 2mm horizon of silt.
One of the principal tasks of micro-
morphology will be to ascertain the
composition and depositional charac-
teristics of this deposit.
Above C4 is a third stratigraphic
unit consisting of the turf wall of
structure D-l. The lower part of the
wall was constructed with dry turf ma-
terial which lacks evidence of red/grey
mottling and which probably orig-
inated within the immediate vicinity
of the site. The bulk of the turf wall is
comprised of turf material (7.5YR 3/2)
with significant iron mottling and
which probably originated from a wet
source. Compression of wet turves
during construction of the structure
may have further contributed to the
mobilization of iron, resulting in the
distinctive red (5YR 3/4) banding seen
in the stratigraphy. These field obser-
vations highlight the use of wetter are-
as in the landscape as a source of
construction material, with the mater-
ial likely coming from the sloping area
west of the modern Hofstaðir farm.
The upper stratigraphic unit repre-
sents the period after which the struc-
ture D-1 was abandoned. Here the
stratigraphy reverts to phases of silt
accumulation, tephra deposition and
short periods of standstill which al-
lowed the incorporation of soil organic
matter. This stratigraphic unit
provides the opportunity to examine
environmental conditions within an
enclosed inbye area, with tephra
stratigraphic markers Hekla 1104/58,
Hekla 1300 and „a” 1477 providing a
secure chronological framework from
which to assess the environment at
Hofstaðir prior to 1500 AD.
Section 2 (Area G)
Four contexts were examined within
this stratigraphic sequence. Contexts 8
and 9 represent the lower horizons and
exhibit complex microstratigraphic
layering. A wide range of soil hues are
evident, from 7.5 YR to 2.5 Y, with
textures that are predominantly silt
and silty loam. These contexts are cur-
rently interpreted as being collapsed
wall or roof turves (C8) and at least
two occupational floor layers (C9)
within which are mixed traces of the
pre-settlement subsoils. Stratigraphic
organization indicates that there has
been substantial disruption of the early
land surface duririg the initial phases
of occupation, presumably associated
with construction of the sunken floor-
ed building. For example, Hekla-3
tephra (10YR 5/3) and the Landnám
131