Saturday, 14 January 2012

Feeding Stonehenge - food residues in Neolithic pots

Lab day today, finishing off the last batch (for now) of pottery samples from Durrington Walls. Bit of background - my main research project at the moment is to investigate patterns of food consumption at Durrington Walls, the Neolithic settlement associated with Stonehenge. This involves selecting pottery from different parts of the site, extracting food remains, and seeing if there are differences across the site. Fatty food residues survive suprisingly well in prehistoric pottery (well, some of it, depending on the preservation conditions and other factors). They can be extracted quite easily in the lab by grinding up a small portion of the pottery and shaking it with solvent. The fatty residues dissolve into the solvent, and can then be identified by injecting the solvent into a GC/MS. In basic terms, the GC/MS seperates out all of the different parts of the food residue so we can identify the different components, and the result is something like this. Each of the peaks is a different lipid. Except the ones labelled with P - those are plastic contamination from the bags that the pottery was stored in after excavation. Pesky plasticisers leach into everything.




I've managed to perfect the extraction process so I can do the basic level of analysis on 3 batches of samples in 3 days, assuming nothing goes wrong in the lab, like running out of furnaced glassware (we put all of the sample tubes and whatnot in the furnace before using them, to get rid of any potential contamination from modern residues).

I quite like being in the lab on weekends. No one else is here so I have loads of bench space and can use all the kit without any hanging around. Soon all the lab work will be finished and I can really get going on the most exciting part - data analysis and interpretation. We already have some preliminary ideas of what might be going on from looking through the data we have so far, I'm excited to see what the results are like after all the statistics and GIS analysis! I just wish it wasn't so cold today (colder than it was over Xmas I'm pretty sure). I keep popping back to the office as the lab is freezing.

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