Daily Archives: May 22, 2009

Rehydroxylation Dating

Science, The Past, , , ,

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.

Saxon Pottery
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.
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I’m not sure what the rate of interest is

Life

The can­cer blog­ging con­tin­ues. See the intro­duc­tion for more details.

Chemo­ther­apy may have side-effects, so I was advised to visit a sperm bank. How badly did this go?

There’s four dimen­sions you can see. Three dimen­sions of space and an extra one of time. How­ever that leaves some mys­ter­ies. For instance why is grav­ity so much weaker than the other forces? Phys­i­cists the­or­ise there are more dimen­sions, pos­sibly eleven, and grav­ity leaks into these. It’s thought that no-one has yet found if these dimen­sions exist. I can con­firm they do. They’re integ­ral to the lay­out of the Queens Med­ical Centre in Not­ting­ham, where the Andro­logy clinic has a sperm bank. The cor­ridors twist and turn in a man­ner that would dis­or­i­ent­ate even the most eager topo­lo­gist. That’s why I ended up in Opthal­mic wing first and asked for dir­ec­tions. If you’re ever in a sim­ilar situ­ation that’s a step you might want to avoid. I’m told there’s sim­ilar prob­lem with people turn­ing up for colono­scop­ies in the Elbowo­logy depart­ment.
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