Wednesday, 10 December 2014

Micrograph of the Month: Krotovinas at Çatalhöyük

Did you know that there is a word for an animal burrow that becomes backfilled with soil/sediment? That word is krotovina! At Catalhoyuk, burrowing by small mammals is probably one of the most destructive forms of bioturbation on site. Ground squirrels, or suslik as they are known in Turkey, have a great time digging their way through the nice soft archaeological sediments, mixing up the deposits as they go. When marking out locations for micromorphology sampling we try and avoid these burrows, as we want to look at intact stratigraphy. Every once in a while however, what looks to be undisturbed deposits turns out to have a hidden burrow when the slide is made. It makes the sample almost useless it terms of analysis, but in this case has given a nice example of bioturbated deposits for my teaching reference collection of slides! I have included pictures of the midden section that these micrographs come from, as it is much easier to understand what a krotovina is at the macroscale. The photo on the left highlights the multiple krotovinas in this section, which are distinctly rounded and tunnel-like. It is always important to refer back to field sections when analysing micromorphology slides, as it helps understand the spatial extent of the deposits that are being studied.


In the micrographs below you can see there that there is a lot of white 'space' - these are void areas, that is, area of space within the deposits. These are the result of the mixing that occurs when the suslik digs through the layers, loosening the deposits and kicking them backwards. The mixing can also be seen in the way all the different materials are randomly orientated. The different layers within the slide become homogenised, as if they have been shaken up and redeposited. This can also be seen clearly when we look at the thin section slide above - I have highlighted the V shaped 'burrow' that cuts through the different layers of ash.


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