Jane Evans from British Geological Survey opens the new term of Café Sci at The Vat and Fiddle with a talk on the unearthing of Richard III and the discovery of a Viking burial site in Weymouth.
Isotopes are different types of elements, they have different weights and different nucleuses. Jane uses a great metaphor to describe the sort of techniques that she uses to investigate these isotopes. Imagine a bowling alley. You would expect children to pick the lighter balls. By putting all of the bowling balls on a shelf you can test this hypothesis. How would we differentiate between children and grannies though? We would need another discrimination such as what empty drinks are lying around – is it coke or is it tea?
Instead of looking at bowling balls, Jane can measure the amounts of specific isotopes to calculate the age of rocks. As well as looking at rock, you can look at bone and proportions of isotopes can tell us certain things:
– Strontium: Geographic origin
– Oxygen: Climate
– Carbon/Nitrogen: Diet
– Lead: Pollution
With rain, heavier isotopes are rained out first – This leads to zonation. So by looking at oxygen isotopes in bone we can tell what water people have been drinking and so we can tell where they have been. Similarly 90% of plants are C3 plants. This mean that they have a low carbon isotope value. Other plants have different isotope values. Hence by looking at the carbon we can tell what plants people have been eating.
For years it was believed that the body of Richard III had just been thrown into the River Soar. In fact there was even a blue plaque put up at the place it was thought to have happened. However, there was no actual contemporary evidence for this ever having happened and so historians in Leicester decided to look for where he “should” have been buried.
Initially, they thought that there would be very little chance that they would ever find the body. They thought that there was a reasonable chance that they could find the church that he was buried in but that would probably be as far as they got. Then, on the first day digging, they found a body.
It had no coffin, the hands were tied and it had a curved spine. The body had head wounds and it clearly a hurried burial. Carbon 14 dating placed the body from the right era and DNA showed links to Richard’s modern descendants on his maternal side.
It takes about 15 years for one of your bigger bones, such as the femur, to completely regenerate while something like a rib only takes two. By looking at the isotope differences in these two bones, Jane can tell how his diet changed after he became king. There was very little difference in the carbon values but big differences in nitrogen and oxygen.
There is more nitrogen in food that is higher up the food chain. Hence it looks like Richard’s diet changed after he became king and he started eating animals that were nearer the top. You can get a real feel for this by looking at what he ate at his coronation banquet.
The change in the oxygen implies that he moved in regards to the climate zone that he lived it. However, in Richard’s case we have full records of everywhere he travelled while he was king. Rather than moving to Cornwall as the data might have suggested, the increase was actually down to the fact that around 20% of the fluid he drank as king was wine.
Jane’s second case study related to a discovery in Weymouth. In 2009 they were building a new road for the 2012 London Olympics and discovered a mass grave. There were around 50 men in a disused quarry and by the way their heads were separated from their bodies, it was clear that they had been beheaded.
Due to the location of the find, it was initially assumed that the bodies might be Roman. However, carbon 14 dating put them between 970 and 1045CE, much later than the Romans and more in Viking times.
Teeth were taken from 10 of the bodies and tested to see if they were from Weymouth. The strontium and oxygen isotopes showed that these people were definitely not from Britain making the largest deposit of non-British people from that era. The bones also showed very low concentration of lead isotopes, far less than would have been found in Britain at the time. In fact this also ruled them out of being from Scandinavia.
So, if these Vikings weren’t rom Scandinavia, where were they from? Well, it looks like they might have come from Poland. One of the dead men may even have come from Russia. Is it possible that the ship they came over one travelled across the coasts of northern Europe picking up a crew?
In fact, were they even “Vikings” at all? Maybe they were pirates or traders. The bodies showed very few battle wounds. There were no women and no children, just males, mainly aged between 16 and 28 with a couple of older men (probably the ship’s captain). Looking at the isotopes in their rib bones, it looked like they hadn’t been in Britain long either.
So, an absolutely fascinating talk to kick of the return of Café Sci. I didn’t realise that you could tell quite so much about people’s lives from the composition of their bones. Jane was a great speaker; passionate and knowledgeable.
Café Sci returns to The Vat and Fiddle on the 9th of November where Richard Alexander from Leicester University will be talking about “Super-massive black holes – cosmic giants at the heart of our galaxies”
Originally published on the On Nottingham website