Tuesday, 11 April 2017

Micrograph of the Month: TBD

You know nothing, Lisa Shillito! This is how I sometimes feel being a micromorphologist, especially one looking at samples that are a different to the contexts I am used to. Here are some more images from the Lufton Roman Villa sample I mentioned last month. I am not actually going to say much about this as I am not entirely sure what it is, and basically am scouting for opinions from fellow geoarchaeologists. This is a small rounded inclusion about 1mm in length, consisting of lots of brownish purple rhombohedral crystals embedded in a yellowish (almost ash-like?) matrix. As you can see, the crystals themselves don't look much different in XPL. The inclusion is located within a layer of mixed microcharcoal and calcareous debris (probably from the lime layer underneath). There are some bits of lime that have a similar appearance, sort of like iron staining of the carbonate. My guess is possibly iron carbonate crystals replacing the calcium? I will definitely be bringing this slide to the DIG conference workshop for opinions!

Unknown rounded inclusion in Roman floor sample and close up of crystals. Left: PPL Right: XPL