Wednesday, 7 November 2012

A curious incident


Corroding sample!
Yesterday's ICP samples are coming along nicely. I'm happy to say nothing had exploded when I went to check on them this afternoon. Today I also started boxing up the last few samples from medieval Riga, and came across this oddity ---->. All of the samples from Riga were waterlogged, and something strange has happened to this one; you can see all that orange spreading across the bottom of the sample? It is some sort of iron staining, and is very clearly seeping from the sides of the tin into the fine grained clay floor part of the sample. There were also lots of little salt crystals all over the surface, and you can see to the centre right a small area at the top of the metal tin has corroded! I'm wondering if there is a metal object in the block somewhere that is degrading?

A few of the other samples had unfortunately started growing mould. In future I will learn to wear a mask when unwrapping waterlogged samples! Hopefully this was just on the surface and will not have impacted the sediments where the slide cut will be made, though I'll be on the lookout for their little fungal hypae.

Slices from the blocks, ready to be cut to slide size



The blocks from September have now set and are in the process of being cut to size ready for mounting on slides. Absolutely beautiful preservation of wood, charcoal, dung (of course) and floors. The slides themselves should be ready by Xmas, I'll have to resist spending the holidays with ny nose down the microscope....

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