Science and Archaeology

A while ago now the SDR team and I visited Thomas Hardye School in Dorchester for their Natural History Science Day. The format of the day was a round robin style event with several different stalls that the children would rotate around. The Natural History Museum were there, the Wildlife Trust were talking about poo, the Jurassic Coast team were looking at fossils, the Bournemouth University team were making soap but there were also many more. Our table introduced the children to science in archaeology, using the Mass Viking Burial that was discovered during the construction of the Weymouth Relief Road. (I know that it’s not prehistory but the science applied is still the same).

Oxford Archaeology

We had 8 minutes with which to introduce the site to each group and then discuss what archaeologists could tell from the bones. Although clearly there was a lot more gleaned by Oxford Archaeology (who excavated the burial and made the video above) we limited ourselves to 5 different scientific techniques.

Sex: By looking at the brow ridges on a skull, the jaw and the bump at the back of the head, combined with the shape of the pelvis you can often identify male and female traits. All of the skeletons in the mass grave appeared to be men.  These videos may help to explain further (apologies for the really irritating guy although what he says is pretty accurate).

University of Colorado Denver Anatomy Lab

So Cool Science Show

Age: Bones and Teeth change as you get older, although it is much easier to age a child than an adult. The ends of bones don’t properly fuse until you are a teenager. Most of the people buried in the grave were aged between 20 and 40.

kids hand bones

Figure 1: Developmental stage differences between (from left to right) 6 months, 6 years, and 8 years of age . Notice the appearance of little bones at the end of longer bones in the middle and right photo: as we get older, these will fuse together to form a single bone. The appearance and fusion of these bones helps anthropologists determine the person’s age http://www.sfu.museum/forensics/eng/pg_media-media_pg/anthropologie-anthropology/

Date of burial: C14 dating looks at the rate of decay of the unstable isotope Carbon 14. Isotopes are atoms that have the same number of protons, but different numbers of neutrons. Carbon has three different isotopes, C12, C13 and C14. C14 is unstable and decays over time, this means it becomes stable.

There is a constant amount of C14 in the air; this gets absorbed into living things, including people’s bones. Once a person dies they stop absorbing carbon and the C14 that was present will start to decay. By comparing the C14 in the bones to that in living organisms we can work out how much decay has happened and therefore how old the bones are. The bones in the mass burial dated to about 1000 years ago, this was the Viking period.

Place of origin: Oxygen isotope analysis looks at the signature of the oxygen molecule within the bones. Some oxygen molecules are lighter than others. These molecules are more likely to rise during evaporation. Imagine this happening over the sea, eventually the oxygen in the water in the clouds will contain many more light oxygen molecules than the sea. When this occurs over land weather and climate will cause different patterns in the water cycle. This results in different places having different ratios of light and heavy oxygen, creating a unique signature.

The oxygen traces in the bones were from all over Scandinavia. This is where the Vikings originate from.

What they ate the night before they died: Cholesterol is a fat. Traces of cholesterol will remain in soils long after the flesh has rotted away. By analysing the fats in the soils from the mass burial archaeologists discovered that the soil from around the stomach and intestine areas contained many more traces of animal fats (and slightly more plant fats) than the soils for elsewhere. This suggests that their last meal was a meaty one.

Conclusion:

I’ll let you put all this evidence together and draw your own conclusions. There is a lot more information about the burial- I deliberately ignored the gruesome stuff for the schools. If you want to know more about the discovery go to

http://weymouthreliefroad.wordpress.com/tag/archaeology/

http://www.bbc.co.uk/news/uk-england-dorset-26453621

The excavation has also now been published and is titled ‘Given to the Ground’ It is on sale online as well as in the Dorset County Museum

Given to the ground: a Viking age mass grave on Ridgeway Hill, Weymouth, L. Loe, A. Boyle and D. Score (2014), £29.00, ISBN 978-0-900341-58-8

 

I have tried to make every effort to ensure any links are accurate, up to date and relevant, however I cannot take responsibility for pages maintained by external providers. Please  let me know if you think something is inappropriate or no longer exists.

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