VSF 2010 Report - Nabo

Combustion Traces
Where previously excavated assemblages from soils in the vicinity of the Viking Age area
had a high proportion of burnt bones related to propable field fertilisation, those associated
with Structures 9 and 10 are less dominated by bones showing combustion traces (Figure 2).
Figure 3. Relative frequency of combustion traces in the Viking age assemblages (U = unburnt bones; W =
white bones, calcined through burning)
Other Taphonomic Factors
Other taphonomic traces, like gnawing and butchery marks, are mostly absent from this
assemblage. Only one chop mark was identified on an ovi-caprine metapodial shaft. Bone
cortex being affected by soil acidity might have played a role in the lack of those traces; bone
surface modifications by chemical or mechanical weathering tend to cause the disappearance
or misinterpretation of butchery marks. Trampling could also have occurred, resulting in bone
fragmentation as shown in Figure 2. Some bone “powder” or “bone butter” was also noted in
the assemblage and during the excavation. This almost total decompositin of the bone is
probably related to the highly acidic (pH 4-5) and well-drained soils, which experience
abundant rainfall and snowmelt, causing almost total leaching of calcium from the bone.
Discussion
The analysis of the whole Viking Age faunal assemblage should be done to optimize
interpretation of the results. A better understanding of subsistence or economic strategies of
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