Thursday, 31 January 2013

University of Edinburgh at the ScARF launch

Since officially starting at Edinburgh at the beginning of January, one of my major tasks has been coordinating the university's stand at the launch of ScARF - the Scottish Archaeological Research Framework, an initiative which highlights current strengths in Scottish archaeological research, and directions for future work. I have learned some valuable lessons from this, firstly that 2 weeks is very little time to coordinate 10 students, produce 10 project flyers and 3 A0 posters, and secondly, no matter how little time you have, never leave printing until the day before, and always get proofs! But, lessons learned (and apologies for spelling some names wrong!), the event yesterday evening went really well, and I was pleased to catch up with many old friends and colleagues. It turns out that I know more people in Edinburgh than I thought!

University of Edinburgh stand at the ScARF launch event
The posters we displayed highlighted all of the postgraduate research in Scottish archaeology in the School of History, Classics and Archaeology. Subjects span early prehistory to the Medieval period, with approaches as diverse as visualisation, ceramic analysis, GIS and osteoarchaeology. It was really interesting to see the range of material that students are working on in the department, and also to have a look at some of the other displays that were on show at the event, which was hosted by the Society of Antiquaries of Scotland in the Royal Society of Edinburgh building. There is a real sense of heritage and its importance here that is very energising, and much potential for collaboration between academia and other parts of the heritage sector that is very exciting.

I highly recommend having a look at the ScARF website - although it is focused on Scottish archaeology, it also has a wealth of background information on cutting edge archaeological science, and the suggestions made for future research are widely applicable outside Scotland as well. And of course, there's all the info on Scottish archaeology! The more I get involved the more I am becoming fascinated by this. It is especially relevant to my work at York on Neolithic Grooved Ware, which actually originated in Orkney. Hopefully more of that to come in future!

Saturday, 26 January 2013

Crusader Castles of the Baltic

I wrote a feature article for Current World Archaeology Magazine on the Ecology of Crusading project, which has just been published in issue 57. It's a brief overview for a general audience, so there's lots of basic info on the environmental and lab methods we are using as well as some of the preliminary results. And of course lots of fab photos of castles, fieldwork and whatnot. I like writing more general articles like this - it's something I can show the parents and they get all excited about. Pages of technical jargon in J. Arch. Sci. and the like never get quite the same reaction.

It's exactly 10 issues since the last piece I wrote for them in issue 47, 2011, on Catalhoyuk under the Microscope, which you can read an excerpt from here:

Monday, 21 January 2013

Micrograph of the Month - Microdebitage

Following on from my post last week about the Neolithic site of Kamiltepe in Azerbaijan, I thought I would share some of the images from the preliminary micromorphology report I did for the 2010 monograph. I loved working on these samples - it's the first time I've worked on a building myself. All of my work at Catalhoyuk has focused on middens, and all of the work on buildings is done by Dr Wendy Matthews (University of Reading), who supervised my PhD. Wendy's work at Catalhoyuk and many other Near Eastern sites is fantastic, and is the starting reference point for my own work in this area! So it was nice to see variety in deposit types - with the middens there is a lot of redeposited material, ashes, charcoal etc, but I have seen suprisingly little of the type of thing you can see here in these images. These show bits of microdebitage embedded in the floor of the building - that's tiny bits of waste chips from the production of stone tools. What is exciting about these is that they appear to be concentrated on a single floor layer, which is then replastered and used for other activities. By carefully looking through each of the floor layers we can build up a picture of the changing use of space over time in this part of the building.

Thursday, 17 January 2013

New year, new job, new news

One of the trenches I worked in at Kamiltepe 2010
I'm almost at the end of my second week in my new position at the School of History, Classics and Archaeology at the University of Edinburgh and it's already been full of busy! The first week I spent gathering quotes for equipment to set up the new microfossil and microscope laboratories, so fingers crossed we can get ordering soon! I also made sure the library was well stocked in all the books and journals that I will need for teaching towards the end of the year, and was really pleased to see how extensive the collections are here. I've already started discussing potential collaborations with other staff members here, and as it turns out there are already several connections with my old BioArCh research group at York, which is very useful! I anticipate I will maintain my involvement with York, and was made a Visiting Research Associate at the beginning of the new year so that I can carry on using the facilities there when needed. Another bit of great news for the new year - the Ancient Kura project, directed partly by the Deutsches Archäologisches Institut, along with the Centre National de la Recherché Scientifique and the National Academy of Sciences Baku, Institute of Archaeology and Ethnography has just recieved funding for the next 3 years' of excavation and analysis. I have been working with Dr Barbara Helwing at one of the key sites, Kamiltepe, since 2010, and my paper on the pilot micromorphology and phytolith analysis should be out in the next few weeks. The funding means that we can extend the pilot and focus on a wider range of buildings and contexts, at Kamiltepe and other sites in Azerbaijan and Georgia, to investigate the lifestyles and subsistence practises of the Neolithic populations in this region.

Shillito, L-M. (2012) Preliminary Microstratigraphic Observations of Ash Deposits and Architectural Materials at Kamiltepe, Azerbaijan. In Ancient Kura 2010–2011. The First Two Seasons of Joint Fieldwork in the Southern Caucasus. Archäologische Mitteilungen aus Iran und Turan 44: 1-189. Ed. by Lyonnet, B., Guliyev, F., Helwing, B., Aliyev, T., Hansen, S. and Mirtskhulava, G. 

Tuesday, 8 January 2013

Fun with phytoliths, part 2

Deflocculating the clay particles. Don't forget to label the beakers.
After carbonate removal and washing away any remaining acid, stage 2 is to get rid of any clays. Again it depends on the type of sample how long this step will take - whilst ashy samples will have more carbonates, they are likely to have minimal clay content. Conversely, these deposits from Elbląg have much more organic and clay components. Again, this is a very straightforward process, but very time consuming. In fact, for samples with a significant clay component, it can take all day! The samples are transferred from their tubes into tall-form 400mL glass beakers. The height and volume of the beaker is important, as we are using a bit of fluid mechanics to seperate out all the clay and non-clay sized particles.

Rinsing beakers into crucibles
Distilled water is added  along with a few mL of sodium hexametaphosphate (otherwise known as Calgon), up to a height of 8cm (it's easiest to mark this out on the side of the beaker). Calgon is a deflocculating agent - a lovely word which is the opposite to coagulation i.e. it encourages the little clay particles to seperate rather than stick together. Then you give it a good stir and let it stand for 1hr 10 mins. During this time, all the particles which are larger than clay-size will settle into the bottom of the beaker, whilst all the clay particles stay in suspension. This is determined by Stokes' Law, which involves a few equations with greek letters. In brief it is based on the radius of a spherical particle, it's velocity in a liquid of particular viscosity, and gravity. Luckily this has all been previously calculated, so all we need to remember is the height of water and the time (I should mention this method is based on Rosen 2005 in the Catalhoyuk monographs).

When the time is up, carefully pour the water + clays down the sink - you sohuld be able to pour most of it away before the silt and sand sized particles start moving from the bottom. As soon as this happens, stop pouring or you'll lose some sample. Then, add the water back up to the mark and repeat, until the water is clear. As you can see in the photo above, some of the samples are very dark. This tends to mean a lot more clay particles, and can take up to 8 hours to remove. When the water is clear, it's time to transfer the samples into crucibles for Stage 3 - removal of organic materials!

Monday, 7 January 2013

Fun with phytoliths, part 1

Weighing out: the container is zeroed and the exact weight of the sample recorded
New year, new samples! Well, newish, they were collected in the summer of 2012 but only made their way to me a few weeks ago. Today is my first day on site at the University of Edinburgh, where I am hoping to set up laboratory facilities for microfossil processing. In the meantime I managed to speedily process this last batch at York. Following drying the samples out in the oven, the next few stages involve removal of different fractions of the soil/sediment. Soil is made up of a range of organic and inorganic components - so to get at the phytoliths, we have to remove any non-phytolith material. It is actually quite an easy lab method, but rather time consuming as there is lots of drying and transferring into different sized containers! As with all sample preparation, the samples are weighed after drying so we can quantify how much material has been processed. The amount of sample that we choose to process depends on how phytolith-rich we expect them to be. Some of the material I have worked on from Catalhoyuk is packed with phytoliths, so we don't need to process too much to get a large number of cells. For these samples, I suspect the concentration will be much lower, and so have weighed out around 1g of each.

Minor/no fizzing with HCl - not much carbonate
Stage 1 - removal of carbonates. This stage is especially important in ashy samples which contain a lot of calcitic material, or with samples from areas with carbonate-rich soils. We add 10% hydrochloric acid to the tubes, and this dissolves any carbonates. Fun chemistry equation, rusting in the back of my brain from chemistry at school:
CaCO3(s) + 2 HCl(aq) --> CaCl2(aq) + CO2(g) + H2O(l)

These samples are from cultural layers in the Baltic, and so the amount of carbonate in them is fairly small. You can see a few bubbles on the sample second from the bottom - if the samples were rich in carbonates, they would all be very bubbly as the acid reacts with the carbonates to produce carbon dioxide. Sometimes they fizz so much the bubbles come all the way up the tube. After the fizzing has stopped, the acid is diluted by adding some distilled water, then removed by centrifuging the sample. It's a good idea to rinse the samples a couple more times to make sure all the acid is gone.

Centrifuge - don't forget to balance
For those of you who might not know what a centrifuge is or how it works, the idea is very much like a washing machine (but without the washing bit). The samples are placed in a holder, which then spins at a very high speed, so that all of the dense/solid material is seperated from the less dense/liquid, and forced into a solid pellet at the bottom of the tube. The liquid can then be poured off, and the sample stays in the bottom of the tube. Centrifuges come in all sizes - from tiny benchtop size to ones that are as big as a washing machine and sit on the floor.

Check back soon for the next thrilling installment: Stage 2 - removal of clays!