I referred to this news story as being potentially the archaeological story of the decade on twitter. Potentially is a good weasel word, but if Rehydroxylation Dating can be independently verified then it could be a more important form of dating than radiocarbon dating. The reason it’s so exciting is that this method will allow archaeologists to date pottery. A couple of warnings before I start. I am not a materials scientist so it’s possible that if something seems odd that’s me messing up the description. The other is I am not on the research team — I’ve merely emailed some questions.
Late Saxon Pottery, but how late? Photo (cc) Wessex Archaeology.
Pottery and other ceramics make up most of the data that you’ll find on an archaeological site. Unfortunately there hasn’t been an easy way to directly date it. The most common way is by style. Pot types and technology come into and out of fashion. Terra sigillata, Samian Ware, is particularly good for this as styles turned over rapidly. However, that no help if all you have is a fragment of cruddy Iron Age pot. Another method would be by association with organic material. If you find some grain in the same strata, you can date that and by association when material was deposited in that strata. There are some problems. Radiocarbon will give you a range of dates rather than one date. This range can be quite wide and it’s prone to contamination. What would be useful would be a way of dating ceramics directly. You can do this with thermoluminesence, which uses natural radioactivity to give a date, but it’s complex and difficult so it’s rarely used. A team mainly based at Manchester University have announced that they can date ceramic materials, such as pottery, tile and brick, through a process called rehydroxylation. It seems to be simpler than both thermoluminesence and radiocarbon dating and much harder to accidentally contaminate. There are some impressive additional uses for the method which could make a lot of excavated material a lot more useful.