Castles and Coprolites

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 th...

80s-tastic plasma lamp (Wikipedia) Today I was mostly preparing lake sediment core samples for ICP. ICP stands for Inductively Coupled Plasma, and comes either in the MS (mass spectrometry) or OES (optical emission spectrometry) variety. Both are methods for measuring the different elements present in a sample. The ICP bit is a 'torch' containing a gas, typically argon, that is ionised by heating it via electromagnetic induction (remember those weird glowing globe plasma lamps?). Still confused? This means there is a coil wrapped around the torch, which produces a very strong electromagnetic field when turned on. The argon gas is ''lit' by an electrostatic spark, and the gas becomes ionised. The sample (dissolved in liquid) is sprayed into the argon flame, and also becomes ionised. As different components in the sample become ionised they gave off a characteristic energy. The MS and OES parts is the bit that detects the elements present. MS does this by measur...

Riga town samples set in resin, ready for cutting into slides Another week of lab work in Reading this week for the Ecology of Crusading project. The samples I boxed up in September for resin impregnation are now ready for cutting, and hopefully some of them will be finished into slides by the end of the week. They look like they've set really well; I was a little worried there would be problems as some of them were quite damp with lots of 'manure' layers, which can sometimes distort when dried or interfere with resin curing. I boxed up a few more samples from medieval Riga (Latvia), and 3 from Święta góra (Poland) today. It's going to be a tremendous amount of microscope work to get them all analysed, but I'm looking forward to it! I also started preparing some lake core samples for ICP analysis today, which was delayed due to some minor hiccups which will hopefully be corrected tomorrow. That should take the rest of the week, with the Association for Envir...