VSF 2010 Report - Nabo

cture 4
38
39
a
b
Figure 3. (a) Structure 4, showing the locations of samples 38 and 39 (post holes outlined in black, paving
stones in grey); (b) Floor [7027] , facing south, prior to taking sample 38, showing some subtle horizontal
lensing, as well as disturbance from soil fauna.
The upper layer is almost entirely composed of earthworm excrements (over 75%).
This layer also contained a significant proportion of iron nodules and iron pseudomorphs
(Figure 5.26), possibly as a result of iron leaching from turf collapse layers into the buried
floor layer below, and so are post-depositional features.
It is worth noting that a particularly large bone fragment was located in this sample,
which was rounded, with smooth edges, indicating that it had been transported – perhaps
trampled into the building from elsewhere. There is unfortunately little to indicate the
original use of Structure 4, except for the organic enrichment of the lowermost part of the
floor.
Sample 39 (Figures 5.11 and 5.12)
This sample, like VSF07-38, had been heavily affected by post-depositional bioturbation and
the original microstructure was lost. This occurred to such an extent that no layer boundaries
were evident and the whole sample was described as one layer. Interestingly, in this sample
there was an inclusion of an aggregate of partially humified peat, containing abundant
phytoliths and diatoms, and stratified, partially decomposed plant matter (Fig. 5.28). This
might indicate that peat had been stored inside the structure, although it is notable no peat ash
was identified on the site, and it does not seem to have been frequently used as a source of
fuel. There were a number of other anthropogenic inclusions in this sample, including a few
pieces of bone, and a high number of charcoal fragments. As this structure did not contain
any combustion features or any other clear indicators of function, and it probably served as a
storage building, the charcoal may be the result of the spreading of ash (subsequently
dissolved and leached, as it was in all other charcoal-rich deposits) as a way of maintaining
the floor and keeping it dry (Milek 2006: 71-8). If indeed this was the case, it would support
the idea proposed during the excavation of this structure, that an effort had been made to keep
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