When the 49-metre mead-hall on the Aska platform mound was torn down, people lifted the large useful stones out of the postholes and then backfilled them with the floor layer that had accumulated over the building’s lifetime. Last summer we collected samples of these fills and Jens Heimdahl identified carbonised grain in them.
On 12 January I received radiocarbon dates for four of these grains from prof. Krąpiec’s lab in Kraków. The dates are quite widely dispersed and demonstrate that there was a lot of old refuse in the floor layer by the time it was shovelled into the postholes. Thus the grain represents a long use period, perhaps the entire use period of the building. It’s not one brief grain-charring event.
If you want a short use-period for the hall (i.e. if you compress it as tightly as these four two-sigma date spans permit), then it was built in 650 and torn down in 880. If instead you want a long use-period (i.e. you inflate the use period as widely as possible within the date spans), then it was built in 590 and torn down in 990.
But we don’t have to rely on the carbonised grain alone. A 1980s trial trench through the platform secured articulated horse bones on the ground surface under the platform that gave a radiocarbon date in 660–880. These 220 years are quite a wide span, reflective of 1980s radiocarbon technology. But it’s enough to show that 590 is too early for the construction of the platform mound.
I sent a new sample from these horse bones to Kraków for analysis with today’s tech, and received the result on 15 January. That horse died between AD 670 and 770, which pushes the earliest possible date for the building project forward only a decade compared to what the 1980s analysis indicated. And one of the carbonised grains from the use-period of the building is likely to date from before 650.
A start date for the construction project around 660 is not surprising, given the building’s layout and the objects we found in the postholes. The new end date for the hall’s use-life after 880 is unexpected, however. The only finds we made that could point to any activity after 790 are a pair of whale-bone gaming pieces. I expect that as we empty more postholes this summer we will start to find more clearly datable Early Viking Period material. A few dirham coins would be most welcome, in fact quite expected given the radiocarbon dates and the elite context.