Utgrävningen av den östligaste storhögen på gravfältet Ormknös, Raä 111, Björkö, Adelsö sn, Uppland

Abstract

The excavation of a large mound, situated 500 m E from the viking-age gravefields at Birka on Bjorko in Malaren,is reported. It appeared that the mound was build in two sequences. In the first stage it was a barrow consisting of a three layered stone-setting covered by a layer of humus mixed gravel. On this barrow, which had a diameter of 17 m and a hight of around 1 m, was later a much
higher mound built. This mound had a diameter of 21 m and a height of 2.7 m. At the edge of the northern part a semiround small stonesetting was attached, cf figs 3,9. The reshaping of the barrow into a mound seems to have happened in the Viking Period although the grave later has been robbed leaving a large depression. On the edge of the depression was however a piece of a honestone found, made of a slate with reddish tint, the so called Telemarkslate, jfr Resi 1987. It is probable that this grave was an inhumation as no fragments of burnt bones were found and secondary inhumation graves are fairly common in mounds, cf Graslund 1980:74. The original grave seemed to have been situated in the NV part of the barrow below the stonesetting. Here was a dark layer rich in phosphate and charcoal found but no traces of bones. In the center of the dark layer was a stone ball of reddish granite found. Analyses of the surface showed that the ball was tooled, cf figs 15-17 and appendix I by Henry Freij. Among the charcoal was a bigger piece of a charred log found. This was dated with 4 samples with conventional ¹⁴C technique (the Stockholm lab.) and two samples
with accelerator (The Uppsala lab.). The latter samples were chosen from what was interpreted as the oldest tree-ring of the log and a piece of a small branch. The statistical evaluation, cf figs 18-22 and appendix II by Henry Freij, of the calibrated datings seems to indicate that the tree, a pine, had been felled around year O and had in itself a high age (around 600 years). This indicates that the pine comes from a forest in which man has have little impact e.g. the grave belongs to the colonisation period of the Bjorko Island. In the period around O graves with hidden stoneballs are known from the Malaren area cf Petre 1981:64. The lack of human bones cremated or uncremated is probably to be explained by the soilcondition (gravel). The size of the barrow from the early Iron Age is noteworthy. It should also be pointed out that in the filling of the mound from the Viking Period pieces of iron ore were found, cf fig ( This gives an interesting glimpse of the social status of the burial situated on the Island of Bjorko but outside the Viking town settlement.