Sudden changes in the final days

We have now closed this years trenches and can conclude that the results and our interpretations changed very fast during the two last days. In the last blog post I wrote that we were pretty confident about having found a house on a plateau. This interpretation was based on the stone filled ditch along the plateaus eastern side. It had close similarities to the wall ditches of the southern and northern plateau houses. Another contributing factor was that the layers within the wall were many, thin, with scattered finds of coal, burnt clay and even Iron Age pottery. They looked like a series of floor layers,similar to these we found on the northern plateau.

Everything changed when we decided to make a deeper test trench on the western side to create a deeper profile and find layers from the actual plateau. Beneath sand and clay layers appeared a dark gray layer which seems to originate from a decomposed organic matter such as turf. When Joakim worked on the layer he found that it covered a massive layer of stones. The soil started to sieve down between the stones! We exposed the stones in narrow search trenches and found that they represented an at least 10 m wide cairn. It is far bigger, but it is hard to determine its size right now. Its height is also uncertain, but we can state that its top is flat and the height is more than 0,75 m. It is man made as the stone material is a mix of esker material, fire cracked stones and larger edged boulders. It is fascinating that no soil lies between the stones.

So where do we stand now before we get our 14C-datings and interpret the data further? We can see that the ditch cuts through layers related to the cairn and the mound. And it is subsequently younger than both the mound and the cairn. The house interpretation is becoming vaguer and a potential function of the ditch as an enclosure feature must be taken into consideration.

We can follow the extension of the ditch on the surface and LiDAR as a nearly 40 m long, shallow depression in the grass. The depression is cut by a hollow road that runs over the hill and this road might originate from the Late Medieval period as it is called - the church road, on a map from 1935. It stretches towards one of the Late Medieval entrances to the church-yard that disappeared in the 19th c. No finds of bricks, mortar or any other typical Late Medieval or later finds have been made in the ditch fill. In the south it also cut by a gravel pit that seems to be very old in comparison with the historical maps, i.e. probably the early 18th c. or earlier. No known houses are placed on the hill/plateau during the 18th c. or later.

The other main question is what the cairn represents and why it is placed partly beneath a mound, partly beneath the plateau. It seems like the cairn has direct stratigraphic contact with mound related layers and in that case we are dealing with an 9th mound in Gamla Uppsala of a size more than 20 m in diameter. It now seems like the plateau is artificial as the cairn runs along its base. But why and when was a mound transformed and incorporated into something which today seems to be a huge plateau? We have loads of questions to discuss and have to await a couple of 14C-samples during the autumn.

A picture taken right after the cairn has been found. The earth probe is down almost all the way in empty space between the stones (c.70 cm). To the left is the mound fill layers.

Next time we will sum up the results from Offerlunden.