Humanities & social sciences research - Archaeology
Trenches excavated in 2004-7 produced a spectacular stratified series of walls, structures and middens (domestic refuse deposits) interleaved with layers of windblown sand, showing the history of activity and land-use here up to an including the Viking period. These layers are packed with environmental deposits such as carbonized seeds and grain, animal and fish bones, industrial metalworking slag and burnt peat and seaweed. The content of the layers changes with time, reflecting changes in economy and society.
The sections of the trench (the sides) are a layer-cake of colourful deposits showing the history of activity and deposition. Each layer is given a separate number (a context number), and soil samples are taken which are then sieved and sorted using a flotation machine, a mechanism which pumps water through the soil and allows the lighter seeds and grain to float to the top where they are collected in a stack of sieves down to 500 microns in mesh size. These are then studied by a professional archaeobotanist, who writes a report. The smaller animal and fish bones are collected in this way (the larger ones by hand) and these are also studied and reported upon by an archaeozoologist. Dating samples are taken from these layers in order to perform radiocarbon and optically-stimulated luminescence dating.
Trench 5 was begun in 2005 when a small test trench in an area covered by geophysics revealed the edge of a stone wall. This expanded to become the corner of a building. The building had been abandoned and filled with windblown sand. From a midden layer above and around the building came a number of sherds of a distinctive grey-blue soapstone known as Steatite, of a type which comes from Shetland and was used extensively for vessels and bowls instead of pottery during the Viking/Norse periods. From these we suspected that the building might be Viking/Norse in date, but had to wait until 2006 for confirmation of this.
Finds from Trench 5 (2006), and steatite
The building showed up in 2005-6 as a corner of stone walls with the interior marked up upstanding stones known as ‘orthostats’, used as walls, room dividers or even furniture. It is a traditional Orkney technique where wood was scarce but good building stone plentiful.