Worms off the Hook

Last time I posted about radiocarbon I reported on an unexpected Iron Age date from the New Laund enclosure. At the time I suggested that the charcoal we dated had been moved into an earlier layer and I fingered the earthworm Lumbricus terrestris as the probable culprit. I can now completely and unreservedly withdraw this accusation.

Just about two weeks ago we had another batch of radiocarbon results back. These were all on charcoal fragments that Denise identified from the excavations at the New Laund and Whitewell Enclosures. Now I’ve had chance to think about what these results mean it is clear that we need to radically reassess our ideas about the New Laund Enclosure.

We have being trying to do two things with radiocarbon at New Laund. First to get dates that were both earlier than the construction of the circle of posts in the middle of the enclosure and then others that were later than its demolition – giving us an idea of not only when it was built but how long it was in use for. We were also trying to get dates from the enclosure ditch, to confirm our suspicion that the circle of posts and the ditch were in use at the same time.

(Very) long term readers may just about be able to recall that early in the 2012 season, when we started to dig the New Laund Enclosure, we fleetingly considered the idea that the site might be Iron Age. Then we started to find large quantities of worked stone tools, showing that there had been lots of either Neolithic or Early Bronze Age activity on this bit of the hill, and came to the conclusion that the features we were digging were likely to be of that date too.

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One of our new dates comes from here, about half way up the fill of the New Laund Enclosure ditch, and it calibrates to somewhere between 390 and 205 BC, right in the middle of the Middle Iron Age.

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On the timber structure itself we have the date from the bottom of this posthole showing construction also started in the 4th or 3rd centuries BC.

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And now we have another one from this upper fill of the same feature with exactly the same calibrated date range: 395  to 350 or 305  to 210 BC. This is excellent,as it allows us to combine the archaeological information with the radiocarbon dates. One radiocarbon date on its own tells you that there is a 94.5% chance that the thing you are dating died between a given range of dates. So the date from the base of the posthole only really told us that the structure was built at some point after 395 BC. Now we have this second date, which should have gone into the ground after the posts were removed, we can now be much more confident that the building, use and demolition of the structure all falls into the period between 395 and 210 BC.

What is round, later prehistoric and made of wood? Now we have an Iron Age date for this structure then the temptation to take our former timber circle, imagine a big round thatched roof on it and call it a roundhouse is very strong. If it is an Iron Age roundhouse it is a very big one. And, of course, the date from the main ditch suggests that it has a big enclosure around it. I am off to look up possible local parallels, which should make a whole blog post all on their own. There is also the question of what was going on at the site in the Late Neolithic or Early Bronze Age to leave all the worked stone artefacts we have found. However, next week’s post, assuming I get all the dissertations marked before then, will be an update on the new results from the Whitewell Enclosure, where the finds and the radiocarbon dates are in much closer agreement.

Rick

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