VSF 2010 Report - Nabo

occupation deposit.
The floor layer in this sample was the thickest of the four taken in this structure,
this being expected as the sample was extracted from a central area of the floor in an area
recorded as having a thicker floor deposit. This layer contained various charcoal
inclusions, many of which had an internal structure visible allowing for the identification
of charred wood (Betula), plant tissues (unidentifiable) and seaweed.
The layer of turf collapse in this sample, like all of the turf layers in this building,
had been affected by post-depositional freeze-thaw processes, resulting in it having a
lenticular structure. It was very mixed and had a notably large bioturbated lens protruding
into the left side.
Sample 39 (Figures 5.7 and 5.8)
In this sample the underlying podzol still has its H and A horizons intact, indicated by a
thin lens of decomposed amorphous organic matter upper part of this layer. This was rich
in grass phytoliths, and was situated in a horizontal orientation, again being evidence of
the ‘crushed’ and buried H horizon, and indicating that the building had not been deturfed.
The boundary between the underlying podzol layer occupation deposit was rather
blurred and unclear in this sample. This is due to the abundant bioturbation that has
blurred the boundaries. This earthworm activity has also transported charcoal into the
natural soil (making up just over 7% of the total layer; see Figure 5.7).
The dark occupation deposit in this sample is less well preserved and includes
earthworm channels and large vughs. However, this layer contained two inclusions of
particular importance to the interpretation of the structure, these being iron hammerscale
(Figure 5.23) and iron slag (Figure 5.24) – direct evidence of the metal working activities
that occurred in this structure.
Structure 4
The primary floors of structure 4 were excavated and sampled in 2007. As mentioned
above, the floors were limited to the eastern half of the structure, where they had
accumulated over flat paving stones, with different floor units identified between different
phases of paving. Samples VSF07-38 and -39 were taken from the clearest and thickest
floor layer, unit [7027], which had covered the entire eastern half of the building (Figure
3a). The samples were pressed down over the exposed floor, and bottomed on a flat paving
stone (Figure 3b).
Sample 38 (Figures 5.9 and 5.10)
Unfortunately the high level of bioturbation in this sample makes it impossible to
determine the original microstructure of the sediment (Figure 5.25). However the sample
was split into two layers on the basis that the lower half was slightly less bioturbated and
contained a higher content of amorphous organic matter.
This lower layer contained c.10% amorphous organic matter, most of which had a
dominant horizontal orientation. This horizontal orientation is possibly the result of organic
material accumulating and being trampled into the floor. The presence of fungal sclerotia
are associated with this high content of decomposed organic matter. This organic matter
could either be related to material stored within the building (if it was a storage building),
or to flooring materials.
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